• Current inactivated influenza vaccines provide protec- influenza viruses are characterized antigenically on the tion when vaccine antigens and circulating viruses share a basis of ferret serum antibody cross-reactivity. (cdc.gov)
  • tively selected codons, and substantially diverse codons, The HA protein of influenza viruses is synthesized as a respectively. (cdc.gov)
  • Influenza viruses cause substantial medical and social mapped, based on laboratory variants selected in the pres- problems throughout the world, and vaccination is the ence of mouse monoclonal antibodies (9,10). (cdc.gov)
  • Of the three types of influenza viruses (A, B, and C), under positive selection by comparing 357 viruses isolated only influenza A and B viruses cause epidemic human dis- from 1984 to 1996 (7). (cdc.gov)
  • responses and are the basis for subtyping influenza A However, the importance of these amino acid positions in viruses. (cdc.gov)
  • Influenza B viruses are not categorized into sub- terms of predicting antibody cross-reactivity is unclear. (cdc.gov)
  • Therefore, we conducted this study to explore the useful- viruses have been in global circulation, and these three ness of these amino acid positions for predicting antigenic viruses are currently included as vaccine components. (cdc.gov)
  • Current inactivated vaccines provide essential protection described in this study could be used to predict vaccine- when the vaccine antigens and the circulating viruses share induced cross-reactive antibody responses in humans, high degree of similarity in the HA protein. (cdc.gov)
  • Infection with influenza viruses can be asymptomatic or result in disease that ranges from mild to severe. (cdc.gov)
  • Changes in influenza viruses can take the form of antigenic drift or antigenic shift. (cdc.gov)
  • Antigenic drift involves small mutations in the genes of influenza viruses that lead to changes in HA and NA that accumulate over time, resulting in the emergence of novel strains that the human immune system may not recognize. (cdc.gov)
  • Antigenic drift, along with waning immunity, results in annual influenza epidemics, since the protection that remains from past exposures to similar viruses is incomplete. (cdc.gov)
  • Antigenic shifts are probably due to genetic recombination (an exchange of a gene segment) between influenza A viruses that affect humans and/or animals. (cdc.gov)
  • Influenza is an acute respiratory disease caused by infection with influenza viruses. (cdc.gov)
  • Influenza viruses can be divided into 4 types: A, B, C, and D. Influenza type C viruses are not associated with severe disease, epidemics, or pandemics, and influenza D viruses primarily affect cattle and are not known to infect or cause illness in people, so neither will be discussed further here. (cdc.gov)
  • Influenza type A viruses are divided into subtypes based on surface proteins called hemagglutinin (HA) and neuraminidase (NA). (cdc.gov)
  • A few bat species were recently shown to be infected by influenza viruses originally designated as new influenza A subtypes H17N10 and H18N11. (cdc.gov)
  • [8,9] However, these viruses were shown to be incompetent for reassortment with other influenza A viruses, a hallmark of the species, indicating that they are not true influenza A viruses. (cdc.gov)
  • Reassortment between influenza A (H1N1) and A (H3N2) viruses resulted in the circulation of A (H1N2) virus during the 2001-02 and 2002-03 influenza seasons. (cdc.gov)
  • In April 2009, a novel influenza A (H1N1) virus, influenza A(H1N1)pdm09-which was different from currently circulating influenza A (H1N1) viruses-emerged and its subsequent spread resulted in the first pandemic of the 21st century. (cdc.gov)
  • Influenza B viruses are not divided into subtypes, but are further broken down into 2 lineages: Yamagata and Victoria. (cdc.gov)
  • Influenza A and B viruses both undergo gradual, continuous change in the HA and NA proteins, known as antigenic drift. (cdc.gov)
  • As a result of these antigenic changes, antibodies produced to influenza viruses as a result of infection or vaccination with earlier strains may not be protective against viruses circulating in later years. (cdc.gov)
  • Antigenic changes also necessitate frequent updating of influenza vaccine components to ensure that the vaccine is matched to circulating viruses. (cdc.gov)
  • Antigenic drift is a kind of genetic variation in viruses, arising from the accumulation of mutations in the virus genes that code for virus-surface proteins that host antibodies recognize. (wikipedia.org)
  • Antigenic drift occurs in both influenza A and influenza B viruses. (wikipedia.org)
  • In 1940s, Maurice Hilleman discovered antigenic drift, which is the most common way that influenza viruses change. (wikipedia.org)
  • As in all RNA viruses, mutations in influenza occur frequently because the virus' RNA polymerase has no proofreading mechanism, resulting in an error rate between 1×10−3 and 8×10−3 substitutions per site per year during viral genome replication. (wikipedia.org)
  • All influenza viruses experience some form of antigenic drift, but it is most pronounced in the influenza A virus. (wikipedia.org)
  • The instability of influenza viruses results in constant, permanent and usually small changes in their antigenic composition, a phenomenon known as antigenic drift, necessitating corresponding annual changes in the composition of influenza vaccines. (who.int)
  • Antigenic analysis demonstrated that viruses in the emerging subclade 3C.3 and subgroup 3C-2012/13 were not well inhibited by antisera generated against the 3C.1 vaccine strains used for the 2012/13 (A/Victoria/361/2011) or 2013/14 (A/Texas/50/2012) seasons. (eurosurveillance.org)
  • Viruses naturally acquire mutations from copying errors in replication. (biopharmadive.com)
  • Influenza viruses are highly contagious and can cause seasonal epidemics, manifesting as an acute febrile illness with variable degrees of severity, ranging from mild fatigue to respiratory failure and death. (medscape.com)
  • Influenza viruses cause a broad array of respiratory illnesses responsible for significant morbidity and mortality in children. (medscape.com)
  • Influenza viruses cause epidemic disease (influenza virus types A and B) and sporadic disease (type C) in humans. (medscape.com)
  • Rapid mutation of hemagglutinin allows viruses to escape adaptive immunity. (crick.ac.uk)
  • Viruses were characterised by their antigenic, genetic and antiviral drug resistance properties. (health.gov.au)
  • Results for A(H3N2) and B/Yamagata viruses suggested that circulating viruses of this subtype and lineage, respectively, had undergone antigenic and/or genetic changes, consistent with the decision by WHO to change recommended strains for the 2015 Southern Hemisphere vaccine. (health.gov.au)
  • The Centre also undertook primary isolation of vaccine candidate viruses directly into eggs. (health.gov.au)
  • A total of 38 viruses were successfully isolated in eggs, of which 1 (B/Phuket/3073/2013) was included in the 2015 Southern Hemisphere influenza vaccine. (health.gov.au)
  • The GISRS network, established in 1952, monitors changes in influenza viruses with the aim of reducing the impact of influenza through the use of vaccines and antiviral medications. (health.gov.au)
  • There are now 5 collaborating centres (Atlanta, Beijing, London, Melbourne and Tokyo) that analyse influenza viruses currently circulating in the human population. (health.gov.au)
  • Two types of influenza cause significant disease in humans: types A and B. Influenza A viruses are further classified into subtypes, based on their surface proteins, haemagglutinin (H) and neuraminidase (N). Thus, currently in circulation are subtypes A(H1N1)pdm09 and A(H3N2), although a number of subtypes have been known to infect humans and birds. (health.gov.au)
  • Influenza B viruses are not classified into subtypes. (health.gov.au)
  • In addition, each year some cases of influenza C are isolated from humans, but as these viruses tend not to cause severe disease, they are not a focus of surveillance. (health.gov.au)
  • During 2014, results were reported by reference to the A/California/7/2009 (H1N1pdm09)-like, A/Victoria/361/2012 (H3N2)-like, B/Massachusetts/2/2012-like (Yamagata lineage), and B/Brisbane/60/2008-like (Victoria lineage) viruses that were recommended for the 2014 influenza vaccine. (health.gov.au)
  • Subtypes which have in the past caused pandemics include the influenza A H1N1, H2N2, H3N2 and H1N1pdm09 viruses, while the H3N2 and H1N1pdm09 viruses continue to cause epidemics as seasonal influenza viruses. (health.govt.nz)
  • Influenza B has two lineages of viruses: B/Victoria and B/Yamagata, which are also associated with outbreaks and epidemics, and account for a significant proportion of the overall burden of influenza. (health.govt.nz)
  • Influenza A and B viruses undergo frequent small changes (mutations) in their segmented RNA genome over time. (health.govt.nz)
  • The new virus subtype has novel H and N surface antigens result from the mixing of genomic segments of two or more influenza A viruses. (health.govt.nz)
  • Other possible mechanisms for the emergence of new influenza viruses are through the adaptation of avian influenza viruses to infect humans and the re-assortment of the genomic segments of multiple viruses (ie, human, avian and pig influenza viruses). (health.govt.nz)
  • While they cost pork producers an average of $3.23 per pig, the viruses, for which the animals can be immunized, only spill over into human populations during rare antigenic shifts. (asbmb.org)
  • The viruses come in four major categories - A, B, C and D - but influenza B viruses do not circulate in animals, C viruses are believed to cause only mild respiratory illnesses in humans and D viruses affect only cattle. (asbmb.org)
  • While these mutations happen frequently within a flu season, the changes are usually minor enough that the existing flu vaccine protects against the new viruses in the short term. (asbmb.org)
  • CDC has antigenically characterized 1,854 influenza viruses [1,506 2009 H1N1 viruses, 225 influenza A (H3N2) viruses, and 123 influenza B viruses] collected by U.S. laboratories since October 1, 2013 by hemagglutination inhibition (HI). (cdc.gov)
  • 1,505 (99.9%) of 1,506 2009 H1N1 viruses tested were characterized as A/California/7/2009-like, the influenza A (H1N1) component of the 2013-2014 Northern Hemisphere influenza vaccine. (cdc.gov)
  • 224 (99.6%) of the 225 influenza A (H3N2) viruses tested have been characterized as A/Texas/50/2012-like, the influenza A (H3N2) component of the 2013-2014 Northern Hemisphere influenza vaccine. (cdc.gov)
  • When they aligned the strains of the vaccines with the circulating viruses, which can evolve over time, they noticed the mutation did not allow the antibodies in humans and animals to bind to the flu viruses. (ajc.com)
  • Furthermore, when scientists compared egg-based vaccines with cell-based vaccines formed by insects or mammalian cells, they discovered both humans and animals with the cell-based vaccine responded significantly better to the circulating viruses. (ajc.com)
  • Influenza A viruses are classified into subtypes on the basis of two surface antigens: hemagglutinin (H) and neuraminidase (N). Three subtypes of hemagglutinin (H1, H2 and H3) and two subtypes of neuraminidase (N1 and N2) are recognized among influenza A viruses that have caused widespread human disease. (canada.ca)
  • Although influenza B viruses have shown more antigenic stability than influenza A viruses, antigenic variation does occur. (canada.ca)
  • Influenza A viruses have predominated overall, with both influenza A(H1N1) and A(H3N2) circulating. (canada.ca)
  • Antigenic drift of avian influenza viruses (AIVs) has been observed in chickens after extended vaccination program, similar to those observed with human influenza viruses. (biomedcentral.com)
  • Vaccination programs produce faster antigenic drifts of human and avian influenza viruses [ 6 ]. (biomedcentral.com)
  • Reverse transcriptase PCR (RT-PCR) was used for the amplification of the HA cleavage site sequence, a marker for the virulence potential of avian influenza viruses [ 8 ]. (biomedcentral.com)
  • While the Covid-19 crisis is far from over, we cannot afford to be complacent about what has long been understood to be a principal health security threat: influenza viruses. (csis.org)
  • Seasonal influenza is defined as predictable outbreaks of respiratory disease caused by various influenza viruses that spread from person to person. (csis.org)
  • While seasonal outbreaks are associated with mutation of the haemagglutinin (HA) protein on the viral surface to escape neutralization by antibodies generated in previous exposures, pandemics result from the introduction of completely new viruses into populations, where there is little pre-existing immunity to that virus 2 . (nature.com)
  • The latter performs the diagnosis for SARS-CoV-2, for influenza A and B and other respiratory viruses as respiratory syncytial virus (RSV), adenovirus, metapneumovirus, parainfluenza 1-4, rhinovirus and some respiratory enteroviruses, coronaviruses NL63/HKU1/229E/OC43 and bocavirus. (hug.ch)
  • For samples that are positive for influenza A and/or B, a detailed characterization of the influenza viruses present in the sample will be performed (subtyping, antigenic proximity to vaccine strains, genotyping and identification of mutations associated with antiviral resistance). (hug.ch)
  • Reduced influenza vaccine efficacy against influenza A(H3N2) viruses has been demonstrated during several consecutive seasons. (hug.ch)
  • Influenza A(H3N2) viruses are more variable than influenza A(H1N1)pdm09 and B viruses. (hug.ch)
  • Each modification/mutation in a virus is likely to cause differences between the vaccine strain and the influenza viruses circulating during the season. (hug.ch)
  • and for yet unknown reasons, they are more frequent in influenza A(H3N2) viruses than in the other two strains. (hug.ch)
  • From the time the influenza vaccine strain is recommended to the actual vaccination event (more than 6 months delay), A(H3N2) viruses are more likely to have undergone mutations, which may result in an antigenic drift potentialy impacting the vaccine effectiveness. (hug.ch)
  • But while all influenza viruses undergo mutations induced by this mode of production, changes in influenza A(H3N2) viruses have an increased tendency to result in antigenic modifications than those of A(H1N1)pdm09 and B viruses. (hug.ch)
  • For further information on the activity of human influenza viruses in Switzerland and on the different tests and methods used to characterize them contact Ana Rita Gonçalves, 022 372 40 81 ou [email protected] . (hug.ch)
  • H3N2 viruses continuously acquire mutations in the hemagglutinin (HA) glycoprotein that abrogate binding of human antibodies. (bvsalud.org)
  • During the 2014-2015 influenza season, clade 3C.2a H3N2 viruses possessing a new predicted glycosylation site in antigenic site B of HA emerged, and these viruses remain prevalent today. (bvsalud.org)
  • Influenza viruses also can cause pandemics, during which rates of illness and death from influenza-related complications can increase worldwide. (cdc.gov)
  • Influenza viruses cause disease among all age groups ( 2--4 ). (cdc.gov)
  • The World Health Organization Collaborating Centre for Reference and Research on Influenza tested 403 isolates of which 261 were positive for influenza, 250 of which were influenza A and 11 were influenza B. Ninety-two per cent of the influenza A viruses were pandemic A(H1N1) 2009, and following antigenic analysis all of these were found to be similar to the current vaccine strain. (who.int)
  • Three viruses (0.9%) were found to be oseltamivir resistant due to an H275Y mutation in the neuraminidase gene. (who.int)
  • However, it may represent the start of more dramatic antigenic drift of the pandemic influenza A(H1N1) viruses that may require a vaccine update sooner than might have been expected," they wrote in the online publication Eurosurveillance. (khaleejtimes.com)
  • Flu viruses mutate constantly - this is why people need a fresh flu vaccine every year. (khaleejtimes.com)
  • Antigenic shift is the process by which at least two different strains of a virus (or different viruses), especially influenza, combine to form a new subtype having a mixture of the surface antigens of the two original strains. (influenzavirusnet.com)
  • Antigenic shift is important for the emergence of new viral pathogens as it is a pathway that viruses may follow to enter a new niche (see figure 1). (influenzavirusnet.com)
  • Influenza viruses which have undergone antigenic shift have caused the Asian Flu pandemic of 1957 , the Hong Kong Flu pandemic of 1968 , and the Swine Flu scare of 1976. (influenzavirusnet.com)
  • Pigs can be infected with both human and avian influenza viruses in addition to swine influenza viruses. (influenzavirusnet.com)
  • Because pigs are susceptible to avian, human and swine influenza viruses, they potentially may be infected with influenza viruses from different species (e.g., ducks and humans) at the same time. (influenzavirusnet.com)
  • The resulting new virus would likely be able to infect humans and spread from person to person, but it would have surface proteins (hemagglutinin and/or neuraminidase) not previously seen in influenza viruses that infect humans, and therefore to which most people have little or no immune protection. (influenzavirusnet.com)
  • Burioni, Roberto title: A Non-VH1-69 Heterosubtypic Neutralizing Human Monoclonal Antibody Protects Mice against H1N1 and H5N1 Viruses date: 2012-04-04 journal: PLoS One DOI: 10.1371/journal.pone.0034415 sha: 6b51562f63de5739f2b7ebf5f9c34365ac6ee545 doc_id: 807 cord_uid: fcffl6m4 Influenza viruses are among the most important human pathogens and are responsible for annual epidemics and sporadic, potentially devastating pandemics. (distantreader.org)
  • In this study, we describe a human monoclonal antibody (PN-SIA49) that recognizes a highly conserved epitope located on the stem region of the HA and able to neutralize a broad spectrum of influenza viruses belonging to different subtypes (H1, H2 and H5). (distantreader.org)
  • Furthermore, we describe its protective activity in mice after lethal challenge with H1N1 and H5N1 viruses suggesting a potential application in the treatment of influenza virus infections. (distantreader.org)
  • The current therapeutic regimen for influenza A viruses is limited to two classes of drugs: the adamantanes (amantadine and rimantadine) and the neuraminidase inhibitors (oseltamivir and zanamivir). (distantreader.org)
  • Contemporary H3N2 influenza viruses have a glycosylation site that alters binding of antibodies elicited by egg-adapted vaccine strains. (flu360.com)
  • To identify the critical components of this virus, mouse-adapted influenza A viruses (Panel A) were modified by Kobasa et al. (wakingupcosts.net)
  • so that these viruses expressed the form of hemagglutinin encoded by the gene of the 1918 Spanish influenza strain (HAsp), alone (Panel C) or in combination (Panel B) with the form of neuraminidase encoded by the gene of the 1918 Spanish influenza strain (NAsp). (wakingupcosts.net)
  • Influenza A is a RNA virus and in general, RNA viruses have a very high rate of mutation, a short generation time and yield a high production of virions after replication in the host's cells. (science20.com)
  • Avian influenza viruses replicate in the gastrointestinal tract while human influenza viruses replicate in the respiratory tract-as conveyed by their differential genetic makeup. (science20.com)
  • ABSTRACT Understanding the genetic evolution of A(H1N1)pdm09 and H3N2 viruses can help better select strains to be included in the annual influenza vaccine. (who.int)
  • There is little information on their evolution in Jordan so this study investigated the genetic and antigenic variability of A(H1N1)pdm09 and H3N2 viruses in Jordan by performing phylogenetic and genetic analyses of the HA and NA genes of A(H1N1)pdm09 and H3N2 viruses between 2011 and 2013. (who.int)
  • Jordanian H1N1 viruses had mutations that are characteristic of antigenic group 6 while H3N2 virus mutations belonged to group 3. (who.int)
  • Influenza viruses are considered one of and NA genes of A(H1N1)pdm09 erated with SeqMan DNA Lasergene the most common causes of respira- and H3N2 viruses in Jordan between 7 software (DNASTAR, Madison, tory infection among humans and they March 2010 and March 2013. (who.int)
  • Influenza A viruses are numbers KU933838-KU933908. (who.int)
  • The Centers for Disease Control and Prevention (CDC) estimate that a small sampling of flu viruses nationwide carry the mutation. (yourlawyer.com)
  • Since last flu season, the CDC enhanced its surveillance in an effort to detect flu viruses resistant to Tamiflu and that increased monitoring has provided the agency with the ability to detect resistant strains quickly, Bresee said. (yourlawyer.com)
  • Bresee also noted that influenza viruses are constantly mutating through a process called antigenic drift, which causes them to change from one season to the next and, sometimes, within a single flu season. (yourlawyer.com)
  • When we noticed it," Bresee said of the resistance problem, "well over 90 percent of all [influenza A] viruses were resistant. (yourlawyer.com)
  • In a recent sampling, Norway had the highest percentage of viruses carrying the mutation. (yourlawyer.com)
  • The high genetic variability of influenza A viruses poses a continual challenge to seasonal and pandemic vaccine development, leaving antiviral drugs as the first line of defense against antigenically different strains or new subtypes. (frontiersin.org)
  • Influenza A viruses are one of the most important respiratory pathogens. (frontiersin.org)
  • Influenza A viruses belong to the Orthomyxoviridae family and have a segmented negative-sense RNA genome ( 3 ). (frontiersin.org)
  • Based on the antigenic properties of these viral glycoproteins, influenza A viruses are classified into different subtypes. (frontiersin.org)
  • ABSTRACT We monitored phenotypic and genotypic susceptibility of influenza viruses circulating in Morocco during 2014-2015 to oseltamivir and zanamivir. (who.int)
  • Throat and nasal swab specimens were collected from outpatients (with influenza-like illness) and inpatients (with severe acute respiratory illness) and tested for influenza viruses using real-time reverse transcription polymerase chain reaction. (who.int)
  • Sixty influenza B viruses isolated from MDCK cells showed no significant resistance to NAIs. (who.int)
  • The two influenza B viruses with reduced susceptibility to oseltamivir show that ongoing NAI susceptibility surveillance is essential. (who.int)
  • Based on the results of outpatient and hospital surveillance, influenza A(H1N1)pdm09 and A(H3N2) viruses continued to co-circulate in the Region, with very few influenza B detections having been reported during this season. (flutrackers.com)
  • The EuroFlu bulletin describes and comments on influenza activity in the 53 Member States in the WHO European Region to provide information to public health specialists, clinicians and the public on the timing of the influenza season, the spread of influenza, the prevalence and characteristics of circulating viruses (type, subtype and lineage) and severity. (flutrackers.com)
  • Of the 1342 influenza A viruses that were subtyped during week 12/2014, 594 (44%) were A(H1N1)pdm09 and 748 (56%) A(H3N2) (Fig. 2a). (flutrackers.com)
  • Since week 40/2013, sentinel and non-sentinel sources have yielded 37 583 influenza detections: 35 897 (95%) were influenza A and 1686 (5%) influenza B viruses (Fig. 2b). (flutrackers.com)
  • Of the 25 143 influenza A viruses that have been subtyped, 14 835 (59%) were A(H1N1)pdm09 and 10 308 (41%) were A(H3N2). (flutrackers.com)
  • In addition, the lineage of 169 influenza B viruses has been determined: 155 (92%) belonged to the B/Yamagata lineage (the lineage of the B virus recommended by WHO for inclusion in trivalent seasonal influenza vaccines) and 14 (8%) to the B/Victoria lineage. (flutrackers.com)
  • Influenza B and C are human viruses do not infect birds. (powershow.com)
  • Wild aquatic birds are the main reservoir of influenza A viruses. (powershow.com)
  • Equine influenza viruses have recently been transmitted to dogs. (powershow.com)
  • The first issue materializes when mutations occur in the influenza viruses grown inside these eggs. (browntth.com)
  • These mutations are called egg-adaptations, and they cause slight differences between the currently circulating viruses and the vaccine strain [5]. (browntth.com)
  • This phenomenon of successive infections by the influenza virus is in marked contrast to the situation with viruses like measles, mumps or small pox where exposure to a single infection induces lifelong immunity. (csiropedia.csiro.au)
  • The genomes of all influenza viruses consist of single-stranded, negative sense RNA. (csiropedia.csiro.au)
  • In influenza A viruses there are 8 segments of RNA coding for eight viral proteins and two non-structural proteins. (csiropedia.csiro.au)
  • The Asian influenza viruses which circulated in man from 1957 to 1968 were H2N2 and the viruses preceding Asian influenza (including the lethal Spanish influenza of 1918) were H1N1, as was the swine influenza pandemic of 2009. (csiropedia.csiro.au)
  • This theory was based on the asymmetric nature of the antigenic cross reactions observed between parent viruses and their mutants selected in the presence of neutralising antibodies. (csiropedia.csiro.au)
  • Since influenza A viruses contain eight separate segments of RNA, genetic re-assortment can occur when cells are infected simultaneously by two or more influenza viruses resulting in progeny viruses that contain some (1, 2, 3 or 4) RNA segments from one parent virus and the remaining (7, 6, 5 or 4) RNA segments from the second virus. (csiropedia.csiro.au)
  • Influenza refers to illness caused by the influenza viruses, but the term is commonly and incorrectly used to refer to similar illnesses caused by other viral respiratory pathogens. (msdmanuals.com)
  • Influenza viruses are classified as type A, B, or C by their nucleoproteins and matrix proteins. (msdmanuals.com)
  • Influenza B viruses may cause milder disease but often cause epidemics with moderate or severe disease, either as the predominant circulating virus or along with influenza A. (msdmanuals.com)
  • Most influenza epidemics are caused by a predominant serotype, but different influenza viruses may appear sequentially in one location or may appear simultaneously, with one virus predominating in one location and another virus predominating elsewhere. (msdmanuals.com)
  • The process by which viruses constantly evolve new strains in order to evade immune responses is called antigenic drift . (blogspot.com)
  • Viruses with a high antigenic distance will be poorly blocked by the current immunological responses and therefore are more likely to diverge from the current flu strains and spread into the following season. (blogspot.com)
  • Influenza A viruses tend to garner most of the attention, but let's not forget that there are two other virus types, B and C. (virology.ws)
  • It would be difficult to distinguish influenza A and B viruses by electron microscopy, but there are differences. (virology.ws)
  • Influenza B viruses cause the same spectrum of disease as influenza A. However, influenza B viruses do not cause pandemics. (virology.ws)
  • Influenza C viruses are somewhat different (there is a nice diagram here ). (virology.ws)
  • Like the influenza A and B viruses, the core of influenza C viruses consists of a ribonucleoprotein made up of viral RNA and four proteins. (virology.ws)
  • Therefore the influenza virion contains 7 RNA segments, not 8 RNAs like influenza A and B viruses. (virology.ws)
  • I know influenza B and C viruses quite well - I did my Ph.D. research on them. (virology.ws)
  • So, basically, influenza C is one more of those viruses that more-or-less just gives you a cold? (virology.ws)
  • Do viruses ever reassort across these lines-like influenza A and C exchanging HA genes or something? (virology.ws)
  • A goal of many research works is to produce universal vaccines that can induce protective immunity to influenza A viruses of various subtypes. (biomedcentral.com)
  • with the HAs of other influenza viruses including seasonal H1N1 viruses as well as the A/South Carolina/1918 and A/New Jersey/1976 H1N1 viruses. (scapca.org)
  • Cloned viruses resistant to HI and antibody neutralization were sequenced to identify mutations, and two unique mutations (D127E and G155E) were identified, both near the antigenic site Sa. (scapca.org)
  • However, in the triple\reassortant pandemic 2009 H1N1 [A(H1N1)pdm09] virus, the and genes had a Eurasian swine origin that had not been previously detected in swine influenza viruses isolated in the United States. (scapca.org)
  • 3 , 4 Because of the importance of antibodies to the virus hemagglutinin (HA) for protection against influenza, the antigenic relationship and relatedness of the A(H1N1)pdm09 virus HA to the HA of seasonal influenza viruses circulating in 2009 2009 was of particular significance. (scapca.org)
  • 5 The net result of the two different evolutionary paths was a substantial antigenic divergence between circulating strains of seasonal H1N1 in humans and the swine H1N1 viruses that gave rise to the 2009 2009 H1N1 pandemic virus. (scapca.org)
  • Several reported studies have attempted to assess the extent of cross\reactivity between antibodies to the 2009 2009 H1N1 pandemic virus and recent seasonal influenza viruses, and to earlier H1N1 isolates such as those from the 1918 H1N1 pandemic or the 1976 swine influenza outbreak in New Jersey. (scapca.org)
  • 6 , 7 , 8 Further, cross\reacting antibodies to the A(H1N1)pdm09 virus appear associated with 1976 swine influenza vaccination, 8 , 9 , 10 consistent with the relatively close genetic relationship between those viruses. (scapca.org)
  • Influenza A(H7N9) viruses remain as a high pandemic threat. (bvsalud.org)
  • We assessed the breadth of the heterologous neutralizing antibody responses against the 3rd and 5th wave A(H7N9) viruses using the 1st wave vaccine sera from 4 vaccine groups: 1. (bvsalud.org)
  • Vaccine group 1 had the highest antibody responses to the vaccine virus and the 3rd/5th wave drifted viruses. (bvsalud.org)
  • Notably, the relative levels of cross-reactivity to the drifted viruses as measured by the antibody GMT ratios to the 5th wave viruses were similar across all 4 vaccine groups. (bvsalud.org)
  • The 1st wave vaccines induced robust responses to the 3rd and Pearl River Delta lineage 5th wave viruses but lower cross-reactivity to the highly pathogenic 5th wave A(H7N9) virus. (bvsalud.org)
  • Since 2022, despite the wide geographic spread of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in wild birds and to poultry worldwide, with sporadic spillover to mammals, only a small number of sporadic human cases of A(H5N1) have been identified. (cdc.gov)
  • However, because of the potential for influenza viruses to rapidly evolve and the wide global prevalence of HPAI A(H5N1) viruses in wild birds and poultry outbreaks, continued sporadic human infections are anticipated. (cdc.gov)
  • Because influenza viruses are constantly changing, CDC performs ongoing analyses of A(H5N1) viruses to identify genetic changes that might allow for spread more easily to and between people, cause serious illness in people, reduce susceptibility to antivirals, affect the sensitivity of diagnostic assays, or reduce neutralization of the virus by vaccine induced antibodies. (cdc.gov)
  • Comprehensive surveillance and readiness efforts are ongoing, and CDC continually takes preparedness measures to be ready in case the risk to people from HPAI A(H5N1) or other novel influenza A viruses changes. (cdc.gov)
  • Since 2005, HPAI A(H5N1) viruses have undergone extensive genetic diversification including the formation of hundreds of genotypes following reassortment with other avian influenza A viruses. (cdc.gov)
  • We investigated these amino acid positions single polypeptide (HA0) that is subsequently cleaved into for predicting antigenic variants of influenza A/H3N2 virus- two polypeptides (HA1 and HA2) and forms into es in ferrets. (cdc.gov)
  • The methods described in this study could be applied to of the HA protein of A/Aichi/2/68 (H3N2) has been deter- predict vaccine-induced cross-reactive antibody responses in humans, which may further improve the selection of vac- mined, and five antigenic sites on the HA1 polypeptide cine strains. (cdc.gov)
  • RESEARCH influenza H3N2 virus cross-reactive antibody data. (cdc.gov)
  • The two influenza A virus subtypes have cocirculated in human populations since 1977: influenza A (H1N1) and A (H3N2). (cdc.gov)
  • Antigenic drift has been responsible for heavier-than-normal flu seasons in the past, like the outbreak of influenza H3N2 variant A/Fujian/411/2002 in the 2003-2004 flu season. (wikipedia.org)
  • The most important strains of human influenza virus are A and B. Influenzavirus A has several subtypes, of which two, H1N1 and H3N2, are currently of epidemiological significance. (who.int)
  • The strains of Influenzavirus A implicated in those pandemics have been identified as H1N1, H2N2 and H3N2, respectively. (who.int)
  • While the early start and higher intensity of the 2012/13 influenza A virus (IAV) epidemic was not unprecedented, it was the first IAV epidemic season since the 2009 H1N1 influenza pandemic where the H3N2 subtype predominated. (eurosurveillance.org)
  • We directly sequenced the genomes of 154 H3N2 clinical specimens collected throughout the epidemic to better understand the evolution of H3N2 strains and to inform the H3N2 vaccine selection process. (eurosurveillance.org)
  • Our data support updating the H3N2 vaccine strain to a clade 3C.2 or 3C.3-like strain or a subclade that has drifted further. (eurosurveillance.org)
  • Seasonal influenza virus A/H3N2 is a major cause of death globally. (crick.ac.uk)
  • Effective vaccine strains need to represent H3N2 populations circulating one year after strain selection. (crick.ac.uk)
  • This happened last flu season, when the targeted H3N2 strain mutated beyond the protective abilities of the vaccine. (asbmb.org)
  • We had a vaccine that, against H3N2, was only 25 percent effective, and we had a virus that was particularly virulent," Fauci said. (asbmb.org)
  • The flu vaccines produced every year and approved for distribution by the Food and Drug Administration are designed to protect against two A strains (an H1N1 and an H3N2) and one B strain, with some quadrivalent formulations protecting against an additional B strain. (asbmb.org)
  • WHO declared the pandemic over in August but H1N1 has now taken over as the main seasonal flu strain circulating almost everywhere but South Africa, where H3N2 and influenza B are more common. (khaleejtimes.com)
  • The current seasonal flu vaccine protects against H1N1, H3N2 and the B strain. (khaleejtimes.com)
  • Flu strains are named after their types of hemagglutinin and neuraminidase surface proteins, so they will be called, for example, H3N2 for type-3 hemagglutinin and type-2 neuraminidase. (influenzavirusnet.com)
  • Peu de renseignements sont disponibles sur les mutations des virus saisonniers de la grippe A(H1N1)pdm09 et H3N2 en Jordanie. (who.int)
  • Afin de remédier à ce problème et d'étudier les variations génétiques et antigéniques des virus A(H1N1)pdm09 et H3N2, nous avons procédé à des analyses génétiques et phylogénétiques des gènes de l'hémagglutinine (HA) et de la neuraminidase (NA) de ces virus, sur la période 2011-2013 en Jordanie. (who.int)
  • Les virus H1N1 jordaniens présentaient des mutations caractéristiques du groupe antigénique 6, tandis que les virus H3N2 appartenaient au groupe 3. (who.int)
  • Two of the drugs, dextromethorphan and ketotifen, displayed a 50% effective dose between 5 and 50 μM, not only for the classic H1N1 PR8 strain, but also for a pandemic H1N1 and a seasonal H3N2 strain. (frontiersin.org)
  • Of 440 specimens, 135 were positive for influenza B Yamagata-like virus, 38 were A(H1N1)pdm09 and 25 were A(H3N2). (who.int)
  • Examples are the Hong Kong virus strain A/England/102/72 (H3N2). (csiropedia.csiro.au)
  • since 1968, most seasonal influenza epidemics have been caused by H3N2 (an influenza A virus). (msdmanuals.com)
  • The most recent pandemic occurred in 2009, when a strain of H1N1 that became called " swine flu " spilled over from pig populations, hosts for several flu strains, to humans in North America. (asbmb.org)
  • While millions of doses of vaccine for H1N1 were manufactured by industry, purchased by the federal government and distributed free of cost, the vaccine doses took months to produce, ultimately arriving late in the pandemic . (asbmb.org)
  • We used high-throughput B cell receptor sequencing of plasma cells produced following AS03-adjuvanted and non-adjuvanted 2009 pandemic H1N1 vaccination, as well as pre-pandemic seasonal influenza vaccination to elucidate the effect of the adjuvant on the humoral immune response. (nature.com)
  • The latest influenza pandemic arose in 2009, and was caused by a swine-origin H1N1 virus (pH1N1), and resulted in an estimated 300,000 deaths within the first 12 months 3 . (nature.com)
  • The 2010 Victorian influenza season was characterized by normal seasonal influenza activity and the dominance of the pandemic A(H1N1) 2009 strain. (who.int)
  • Since it broke out in March 2009 and spread globally, the H1N1 swine flu virus has been very stable with almost no mutation. (khaleejtimes.com)
  • While H1N1 turned out not to be especially deadly, it spread globally within weeks and killed more children and young adults than an average strain does. (khaleejtimes.com)
  • The virus has changed little since it emerged in 2009, however, in this report we describe several genetically distinct changes in the pandemic H1N1 influenza virus," Barr's team wrote in the report. (khaleejtimes.com)
  • Already this variant virus has been associated with several vaccine breakthroughs in teenagers and adults vaccinated in 2010 with monovalent pandemic influenza vaccine (protecting against only H1N1) as well as a number of fatal cases from whom the variant virus was isolated," they wrote. (khaleejtimes.com)
  • If you haven't heard of swine flu - Influenza A H1N1 - by now. (science20.com)
  • Although a H1N1 vaccine is a few months off and would undoubtedly cure your hysteria, perhaps in the mean time learning more about thine swine flu enemy will lessen your inner fears of the microbial unknown. (science20.com)
  • L'analyse a porté sur les séquences complètes des gènes de l'HA et de la NA de 16 échantillons positifs au virus H1N1 prélevés dans le cadre de cette étude, ainsi que sur 21 séquences publiées de l'HA et 20 séquences publiées de la NA, issues de virus jordaniens disponibles sur les bases de données de gènes en ligne. (who.int)
  • The Tamiflu resistant mutation has occurred in A/H1N1, one of the main circulating strains causing flu this year. (yourlawyer.com)
  • Dextromethorphan treatment of ferrets infected with a pandemic H1N1 strain led to a reduction in clinical disease severity, but no effect on viral titer was observed. (frontiersin.org)
  • A novel sequence-based antigenic distance measure for H1N1, with application to vaccine effectiveness and the selection of vaccine strains. (blogspot.com)
  • Is there a difference between being diagnosed with Influenza A and H1N1? (virology.ws)
  • Following a challenge with influenza A/H1N1 virus, survival rates and lung index of mice were observed. (biomedcentral.com)
  • In comparison with the group of mice given phosphate-buffered saline (PBS), the mice vaccinated with rL H5 showed reductions in lung index and viral replication in the lungs after a challenge with influenza A/H1N1 virus. (biomedcentral.com)
  • After the mice were vaccinated with rL H5, cross-protective immune response was induced, which was against heterosubtypic influenza A/H1N1 virus. (biomedcentral.com)
  • The mice were then challenged with influenza A/H1N1 virus. (biomedcentral.com)
  • We found that vaccination with rL H5 provided cross-protection against a lethal challenge with an antigenically distinct influenza A/H1N1 virus and produced significant changes in the levels of some cytokines and the percentages of both IFN-γ + CD4 + and IFN-γ + CD8 + T cells in lung and spleen. (biomedcentral.com)
  • Upon its reemergence in 1977 and until 2009, further antigenic drift of the H1N1 HA Lesinurad occurred. (scapca.org)
  • Subsequently, there was an increased genetic and antigenic diversity in the swine H1N1 HA. (scapca.org)
  • To facilitate antigenic characterization of the A(H1N1)pdm09 HA, we generated a panel of murine monoclonal antibodies (mAbs) to the HA of A/California/04/2009. (scapca.org)
  • Antigenic drift is the primary reason people can get influenza more than once and why it is necessary to annually review and update the composition of influenza vaccines. (cdc.gov)
  • Drift occurs in all three types of influenza virus (A, B, C). (cdc.gov)
  • Confusion can arise with two very similar terms, antigenic shift and genetic drift. (wikipedia.org)
  • The rate of antigenic drift is dependent on two characteristics: the duration of the epidemic, and the strength of host immunity. (wikipedia.org)
  • Antigenic drift allows for evasion of these host immune systems by small mutations in the hemagglutinin and neuraminidase genes that make the protein unrecognizable to pre-existing host immunity. (wikipedia.org)
  • Antigenic drift is this continuous process of genetic and antigenic change among flu strains. (wikipedia.org)
  • To meet the challenge of antigenic drift, vaccines that confer broad protection against heterovariant strains are needed against seasonal, epidemic and pandemic influenza. (wikipedia.org)
  • citation needed] Antigenic drift should not be confused with antigenic shift, which refers to reassortment of the virus' gene segments. (wikipedia.org)
  • Phylogenetic analyses indicated that multiple co-circulating clades and continual antigenic drift in the haemagglutinin (HA) of clades 5, 3A, and 3C, with the evolution of a new 3C subgroup (3C-2012/13), were the driving causes of the epidemic. (eurosurveillance.org)
  • Over time, these mutations can accumulate, resulting in what's known as "antigenic drift. (biopharmadive.com)
  • This antigenic drift necessitates regular vaccine updates. (crick.ac.uk)
  • Experts select strains based on experimental measurements of antigenic drift and predictions made by models from hemagglutinin sequences. (crick.ac.uk)
  • We developed a novel influenza forecasting framework that integrates phenotypic measures of antigenic drift and functional constraint with previously published sequence-only fitness estimates. (crick.ac.uk)
  • Forecasts informed by phenotypic measures of antigenic drift consistently outperformed previous sequence- only estimates, while sequence-only estimates of functional constraint surpassed more comprehensive experimentally-informed estimates. (crick.ac.uk)
  • Importantly, the best models integrated estimates of both functional constraint and either antigenic drift phenotypes or recent population growth. (crick.ac.uk)
  • 4-9 More frequent, minor mutations (antigenic drift), cause substantial variability in the impact of seasonal epidemics. (health.gov.au)
  • This 'antigenic drift' leads to the emergence of new antigenic variants or virus strains. (health.govt.nz)
  • Because of this ongoing antigenic drift, seasonal influenza virus vaccine formulations are reviewed by the WHO bi-annually. (health.govt.nz)
  • Unfortunately, influenza vaccine composition needs to be updated annually due to antigenic shift and drift in the viral immunogen hemagglutinin (HA). (mdpi.com)
  • Furthermore, over time, antigenic variation (antigenic drift) within a subtype may be so marked that infection or vaccination with one strain may not induce immunity to distantly related strains of the same subtype. (canada.ca)
  • These findings support recent concerns about the challenge of AIV antigenic drift and influenza epidemics. (biomedcentral.com)
  • Antigenic shift is contrasted with antigenic drift , which is the natural mutation over time of known strains of influenza (or other things, in a more general sense) which may lead to a loss of immunity, or in vaccine mismatch. (influenzavirusnet.com)
  • Antigenic drift occurs in all types of influenza including influenza virus A, influenza B and influenza C. Antigenic shift, however, occurs only in influenzavirus A because it infects more than just humans. (influenzavirusnet.com)
  • Preventive vaccination has historically been the most efficient measure of influenza control, but this approach presents important limitations due to the accumulation of antigenic mutations in the virus, known as antigenic drift. (distantreader.org)
  • The report highlights another likely origin of a more pathogenic virus through the current advent of antigenic drift. (cuencahighlife.com)
  • Most often, it is due to mutations from antigenic drift or egg adaptation. (flu360.com)
  • In between epidemics, minor influenza genetic changes occur (antigenic drift). (science20.com)
  • antigenic drift which occurs within influenza virus subtypes and antigenic shift to new subtypes such as the emergence of Asian influenza in 1957 and Hong Kong influenza in 1968. (csiropedia.csiro.au)
  • Antigenic drift refers to relatively minor, progressive mutations in preexisting combinations of H and NA antigens, resulting in the frequent emergence of new viral strains. (msdmanuals.com)
  • The sharp rise in influenza-associated acute respiratory illnesses that occurs during annual seasonal epidemics results in increased numbers of visits to physicians' offices, walk-in clinics, and emergency departments. (cdc.gov)
  • Seasonal influenza epidemics also impose a considerable economic burden in the form of hospital and other health care costs and lost productivity. (who.int)
  • In the United States of America, for example, estimates in 1986 put the cost of influenza epidemics to the economy at US$ 5000 million per year. (who.int)
  • The WHO influenza programme was established in 1947 with two main functions: to assist in planning for the possible recurrence of an influenza pandemic, and to devise control methods to limit the spread and severity of seasonal epidemics. (who.int)
  • 1-3 Even in the absence of such pandemics, seasonal influenza epidemics cause substantial burden of morbidity and mortality annually. (health.gov.au)
  • Since then, Serfling's model has been applied in a number of temperate countries (USA, 13,14 France, 14 Australia, 14 Italy 15 ) to demonstrate that excess mortality occurring during winter months is associated with pandemic and seasonal epidemics of influenza. (health.gov.au)
  • Influenza epidemics occur each year. (health.govt.nz)
  • For these reasons, major epidemics of respiratory disease caused by new variants of influenza continue to occur. (canada.ca)
  • Epidemics of influenza typically occur during the winter months in temperate regions and have been responsible for an average of approximately 36,000 deaths/year in the United States during 1990--1999 ( 1 ). (cdc.gov)
  • That's arguably a good year considering Influenza A also makes a recurring appearance every 10 to 15 years as a highly virulent form that is responsible for epidemics. (science20.com)
  • Every 10 to 15 years, influenza undergoes a dramatic genetic change ( antigenic shift ) which as described, is responsible for epidemics/pandemics. (science20.com)
  • Thus, antiviral drugs are an essential component of pandemic response scenarios and play an important role in reducing disease severity during seasonal influenza epidemics. (frontiersin.org)
  • Influenza, one of the most common infectious diseases, is a highly contagious airborne disease that occurs in seasonal epidemics and manifests as an acute febrile illness with variable degrees of systemic symptoms, ranging from mild fatigue to respiratory failure and death. (medscape.com)
  • Influenza virus Influenza history Historical records indicate flu-like epidemics throughout recorded history. (powershow.com)
  • Their data showed conclusively that the emergence of new influenza virus epidemics was associated with the accumulation of point mutations in the virus coat proteins. (csiropedia.csiro.au)
  • These new strains may cause seasonal epidemics because protection by antibody generated to the previous strain is decreased. (msdmanuals.com)
  • Influenza causes widespread sporadic illness yearly during fall and winter in temperate climates (seasonal epidemics). (msdmanuals.com)
  • If one of these new forms of an antigen is sufficiently different from the old antigen, it will no longer bind to the antibodies or immune-cell receptors, allowing the mutant virus to infect people who were immune to the original strain of the virus because of prior infection or vaccination. (wikipedia.org)
  • Yet the data should ease some of the concerns that mutations will make the U.K. variant, expected to become more prevalent in the coming months, more resistant to vaccination. (biopharmadive.com)
  • Vaccination is the primary intervention used to curb influenza virus infection, and the WHO recommends immunization for at-risk individuals to mitigate disease. (mdpi.com)
  • There are a number of alternate vaccination strategies in current development which may circumvent the need for annual re-vaccination, including new platform technologies such as viral-vectored vaccines. (mdpi.com)
  • The Mexican aviculture system offers an excellent model to study AIV genetic evolution under high vaccination pressure for two important grounds: i) avian influenza vaccination is a regular veterinary practice, and ii) poultry systems are characterized by high avian population density per production unit. (biomedcentral.com)
  • Of more immediate concern, experts warn that if Americans do not practice appropriate prevention measures such as seeking influenza vaccination, washing their hands, social distancing, and wearing a mask, circulating seasonal influenza and Covid-19 will exacerbate one another, adding further strain to an already overburdened health system. (csis.org)
  • vii The CDC released a report in mid-September predicting that Covid-19 interventions and influenza vaccination could reduce influenza transmission in the 2020-2021 season. (csis.org)
  • For example, only 49 percent of Americans got an influenza vaccination in 2018-2019. (csis.org)
  • For pandemic influenza vaccination, this suggests that the adjuvant could improve B cell responses by either increasing activation of naïve B cells, or by increasing the activation and adaptation of pre-existing memory B cells generated through infection or immunization with seasonal influenza from earlier years to become specific towards the pandemic strain 11 . (nature.com)
  • and 5) the assessment of vaccine supply, timing of influenza vaccination, and prioritization of inactivated vaccine in shortage situations. (cdc.gov)
  • Influenza vaccination is the primary method for preventing influenza and its severe complications. (cdc.gov)
  • Vaccination is associated with reductions in influenza-related respiratory illness and physician visits among all age groups, hospitalization and death among persons at high risk, otitis media among children, and work absenteeism among adults ( 8--18 ). (cdc.gov)
  • Adults 65+ experience age-related decline of the immune system and thus may be less able to mount a sufficient immune response to vaccination, leaving them more vulnerable to influenza infection and its complications. (flu360.com)
  • Educate patients about vaccination with FLUAD QUADRIVALENT (Influenza Vaccine, Adjuvanted). (flu360.com)
  • Influenza vaccination should not be delayed to procure a specific vaccine preparation if an appropriate one is already available. (medscape.com)
  • Second, by the mid-1940s, IAV had varied sufficiently to enable it to completely evade protection following vaccination with a 1934 strain. (doctorschierling.com)
  • Recent observations have provided convincing evidence that reduced VE after sequential influenza vaccination is a real phenomenon. (doctorschierling.com)
  • Pandemics can result from antigenic shift because antibodies against other strains (resulting from vaccination or natural infection) provide little or no protection against the new strain. (msdmanuals.com)
  • Using human post\vaccination sera, however, there were no differences in HI titer between A/California/04/2009 and either escape mutant, suggesting that these single mutations were not sufficient to abrogate a protective antibody response to the vaccine. (scapca.org)
  • Vaccination of mice with adjuvanted S2D14 elicited higher cross-neutralizing antibody titers than adjuvanted S-2P against the SARS-CoV-2 Wuhan strain and four variants of concern. (bvsalud.org)
  • This results in a new strain of virus particles that is not effectively inhibited by the antibodies that prevented infection by previous strains. (wikipedia.org)
  • One of the changes was at a binding site, raising concerns the antibodies stimulated by vaccines wouldn't be able to attach and block the virus as readily. (biopharmadive.com)
  • used phage display libraries, and surface plasmon resonance to determine binding locations, and affinity of the antibodies produced in response to both adjuvanted and non-adjuvanted pandemic influenza vaccines 12 , 13 . (nature.com)
  • research shows it is a target for antibodies and therefore a target for diagnostics, vaccines and therapeutic development (20). (sciencepolicyconference.ca)
  • In contrast, the stem region of HA, formed mostly by the HA2 subunit, is relatively conserved among different influenza A subtypes [19] and indeed could represent an universal target for the development of cross-neutralizing monoclonal antibodies. (distantreader.org)
  • Next-generation vaccines that utilize T cells could potentially overcome the limitations of current influenza vaccines that rely on antibodies to provide narrow subtype-specific protection and are prone to antigenic mismatch with circulating strains. (mdpi.com)
  • To facilitate prospective surveillance for such evolution, we map how convalescent serum antibodies are impacted by all mutations to the spikes receptor-binding domain (RBD), the main target of serum neutralizing activity. (scitok.com)
  • Binding by polyclonal serum antibodies is affected by mutations in three main epitopes in the RBD, but there is substantial variation in the impact of mutations both among individuals and within the same individual over time. (scitok.com)
  • Therefore, antibodies that bind to the HA protein successfully clear the virus, which is why it is vital for the virus to evolve mutations that enable it to escape those antibodies. (blogspot.com)
  • The antibodies to influenza virus were detected using hemagglutination inhibition (HI). (biomedcentral.com)
  • Three types of influenza virus are known to affect humans: A, B, and C. Type A influenza has subtypes determined by the surface antigens hemagglutinin (HA) and neuraminidase (NA). (cdc.gov)
  • The greatest public health concern lies in the tendency of Influenzavirus A to change suddenly and markedly, either through mutation or through the exchange of influenza virus genes or through the transfer of whole virus between host species into novel, genetically distinct subtypes, in a process known as antigenic shift. (who.int)
  • New influenza A virus subtypes emerge periodically that have caused pandemics in humans. (health.govt.nz)
  • This has provided hope for the design of a universal vaccine able to prime against diverse influenza virus strains and subtypes. (mdpi.com)
  • With the exception of bat-associated subtypes ( 4 ), all influenza A virus subtypes can be found in wild aquatic birds, which are their natural reservoir. (frontiersin.org)
  • The CDC analyzes the vaccine subtypes each year and makes any necessary changes for the coming season on the basis of worldwide trends. (medscape.com)
  • Traditionally, the vaccine was trivalent (ie, designed to provide protection against three viral subtypes, generally an A-H1, an A-H3, and a B). The first quadrivalent vaccines, which provide coverage against an additional influenza B subtype, were approved in 2012 and were made available for the 2013-2014 flu season. (medscape.com)
  • Antigenic shift involves an abrupt, major change in one or both surface antigens (H or H-N combination). (cdc.gov)
  • In the influenza virus, the two relevant antigens are the surface proteins, hemagglutinin and neuraminidase. (wikipedia.org)
  • The mutations can occur in the coding regions responsible for H and N surface antigens. (health.govt.nz)
  • Viral antigens included in influenza vaccines are routinely updated in an attempt to avoid antigenic mismatches. (ajc.com)
  • Affected species include other mammals and birds, giving influenza A the opportunity for a major reorganization of surface antigens. (influenzavirusnet.com)
  • Types distinguished by antigenic differences in matrix and nucleoprotein antigens. (powershow.com)
  • Antigenic shift refers to the relatively rare development of new combinations of H and/or NA antigens, which result from reassortment of subunits of the viral genome. (msdmanuals.com)
  • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern challenge the efficacy of approved vaccines, emphasizing the need for updated spike antigens. (bvsalud.org)
  • Antigenic high degree of similarity in hemagglutinin protein. (cdc.gov)
  • Five anti- variants selected serologically are then tested for antibody genic sites in the hemagglutinin protein have been pro- cross-reactivity in human sera to evaluate the potential posed, and 131 amino acid positions have been identified cross-protection against the antigenic variants provided by in the five antigenic sites. (cdc.gov)
  • In addition, 20, 18, and 32 amino acid positions in the hemagglutinin protein have been iden- the current vaccines and to select vaccine strains for the tified as mouse monoclonal antibody-binding sites, posi- next season (2,3). (cdc.gov)
  • In human populations, immune (vaccinated) individuals exert selective pressure for single point mutations in the hemagglutinin gene that increase receptor binding avidity, while naive individuals exert selective pressure for single point mutations that decrease receptor binding avidity. (wikipedia.org)
  • For example, if a pig was infected with a human influenza virus and an avian influenza virus at the same time, an antigenic shift could occur, producing a new virus that had most of the genes from the human virus, but a hemagglutinin or neuraminidase from the avian virus. (influenzavirusnet.com)
  • Hemagglutinin (H) is a glycoprotein on the influenza viral surface that allows the virus to bind to cellular sialic acid and fuse with the host cell membrane. (msdmanuals.com)
  • The data focuses on one influenza gene in particular, the hemagglutinin (HA) because the protein it codes seems to drive the antibody response. (blogspot.com)
  • The major influenza C virus envelope glycoprotein is called HEF (hemagglutinin-esterase-fusion) because it has the functions of both the HA and the NA. (virology.ws)
  • In this study, mice were vaccinated with recombinant virus vaccine (rL H5), in which the hemagglutinin (HA) gene of influenza A/H5N1 virus was inserted into the LaSota Newcastle disease virus (NDV) vaccine strain. (biomedcentral.com)
  • We discuss the different vectored vaccines that have been or are currently in clinical trials, with a forward-looking focus on immunogens that may be protective against seasonal and pandemic influenza infection, in the context of viral-vectored vaccines. (mdpi.com)
  • The consequences of seasonal and pandemic influenza are well documented. (csis.org)
  • Banzhoff A, Pellegrini M, Del Giudice G, Fragapane E, Groth N, Podda A. MF59-adjuvanted vaccines for seasonal and pandemic influenza prophylaxis. (flu360.com)
  • The United States should strongly support universal influenza vaccine (UIV) development. (csis.org)
  • Getting us to a universal influenza vaccine requires collaboration and new thinking. (sabin.org)
  • The world needs a universal influenza vaccine (UIV) - one that is long lasting with the ability to protect against a broad spectrum of mutations. (sabin.org)
  • Chasing seasonal influenza - the need for a universal influenza vaccine. (flu360.com)
  • An antigenic shift may result in a worldwide pandemic if the virus is efficiently transmitted from person to person. (cdc.gov)
  • A second type of change is antigenic shift, also discovered by Hilleman, where the virus acquires a completely new version of one of its surface-protein genes from a distantly related influenza virus. (wikipedia.org)
  • Based on historical patterns, influenza pandemics can be expected to occur, on average, three to four times each century when new viral strains emerge by antigenic shift and are readily transmitted from person to person. (who.int)
  • Influenza, an acute viral disease of the upper respiratory tract, is a major threat to public health worldwide because of its capacity for distinct mutation (antigenic shift) that can result in rapid spread through populations and widespread morbidity and mortality. (health.gov.au)
  • Influenza can also undergo a more significant and abrupt genomic change called antigenic shift, in part due to the mixing of strains in animals like birds or pigs. (sabin.org)
  • Antigenic shift results in a completely new strain against which humans have little or no immunity-potentially causing an influenza pandemic. (sabin.org)
  • The term antigenic shift is more often applied specifically (but is not limited) to the influenza literature, as it is the best known example (e.g. visna virus in sheep). (influenzavirusnet.com)
  • Antigenic shift is a specific case of reassortment or viral shift that confers a phenotypic change. (influenzavirusnet.com)
  • Illustration of potential influenza antigenic shift. (influenzavirusnet.com)
  • One increasingly worrying situation is the possible antigenic shift between avian influenza and human influenza. (influenzavirusnet.com)
  • This antigenic shift could cause the formation of a highly virulent virus. (influenzavirusnet.com)
  • At the same time Dr Graeme Laver at the John Curtin School of Medical Research, Australian National University, and Dr Robert Webster from St Jude Children's Research Hospital, Memphis, Tennessee had obtained evidence (using peptide mapping) for a different mechanism for antigenic shift. (csiropedia.csiro.au)
  • Typical features of influenza include abrupt onset of fever and respiratory symptoms such as cough (usually nonproductive), sore throat, and coryza, as well as systemic symptoms such as headache, muscle aches, and fatigue. (cdc.gov)
  • Influenza is one of the most significant causes of acute upper respiratory tract infections worldwide. (medscape.com)
  • 1 ] Influenza C is associated with mild cases of upper respiratory infection. (health.govt.nz)
  • Of 5,650 specimens tested and reported during week 11 by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories, 495 (8.8%) were positive for influenza. (cdc.gov)
  • WHO and NREVSS collaborating laboratories located in all 50 states, Puerto Rico, and Washington D.C. report to CDC the number of respiratory specimens tested for influenza and the number positive by influenza virus type and influenza A virus subtype. (cdc.gov)
  • Person-to-person transmission of influenza virus occurs through droplets from the respiratory tract that are spread by direct contact, through coughing or sneezing, or by hands contaminated with respiratory secretions. (canada.ca)
  • National influenza surveillance is coordinated through the Immunization and Respiratory Infections Division (IRID), Public Health Agency of Canada (PHAC). (canada.ca)
  • Clinical consultation rates for influenza-like illness (ILI) and/or acute respiratory infection (ARI) returned to pre-season or below baseline levels in most of the countries in the WHO European Region. (flutrackers.com)
  • Although respiratory infections can be classified by the causative virus (eg, influenza), they are generally classified. (msdmanuals.com)
  • Nearly all adults have been infected with influenza C virus, which causes mild upper respiratory tract illness. (virology.ws)
  • That's correct - influenza C causes mild upper respiratory tract infections with cold-like symptoms. (virology.ws)
  • The RSVPreF3-AS01 vaccine, containing the respiratory syncytial virus (RSV) prefusion F protein and the AS01 adjuvant, was previously shown to boost neutralization responses against historical RSV strains and to be efficacious in preventing RSV-associated lower respiratory tract diseases in older adults. (bvsalud.org)
  • Hospitalisations and deaths from influenza are often due to secondary complications such as pneumonia that occur well after the initial influenza virus infection. (health.gov.au)
  • If this new virus causes illness in people and can be transmitted easily from person to person, an influenza pandemic can occur. (influenzavirusnet.com)
  • It can also occur when the prevalent circulating influenza strains are different from WHO predictions. (flu360.com)
  • The more copies a virus makes of itself, the more chance there is that mutations can occur. (abc-oriental-rug.com)
  • Despite this inter- and intra-person heterogeneity, the mutations that most reduce antibody binding usually occur at just a few sites in the RBDs receptor binding motif. (scitok.com)
  • Reassortment among the three influenza types (A, B, C) does not occur. (virology.ws)
  • A significantly higher percentage of ILI patients were swabbed in 2010 compared to 2003-2008, but similar to 2009, with a similar percentage being positive for influenza as in previous years. (who.int)
  • This is consistent with the decline in the percentage of ILI and ARI sentinel specimens testing positive for influenza. (flutrackers.com)
  • At least four pandemics of influenza occurred in the 19th century, three in the 20th century, and one thus far in the 21st century. (cdc.gov)
  • since the late 19th century, five antigenic shifts have led to pandemics in 1889-1891, 1918-1920, 1957-1958, 1968-1969, and 2009-2010. (cdc.gov)
  • the past, such new strains have generated pandemics with high lethality and causing great social disruption. (who.int)
  • Thus, in the 20th century, the great influenza pandemic of 1918-1919, which caused an estimated 40 to 50 million deaths worldwide, was followed by pandemics in 1957-1958 and 1968-1969. (who.int)
  • Yet, history has proven the reality of this threat with influenza pandemics in 1918, 1957-58, 1968, and 2009. (csis.org)
  • Influenza pandemics require rapid deployment of effective vaccines for control. (nature.com)
  • Influenza virus causes seasonal outbreaks of clinical influenza, and has been responsible for four pandemics over the last 100 years 1 . (nature.com)
  • The capacity to rapidly develop and manufacture effective vaccines in large quantities is key in combating influenza pandemics. (nature.com)
  • So what is it about Influenza A that makes it a top candidate for pandemics? (science20.com)
  • For this reason, seasonal vaccines need to be annually reformulated based upon the forecasting of viral strains that will circulate in the coming influenza season. (distantreader.org)
  • The major advantage conferred by a segmented genome comes into play during coinfection which is when a cell becomes infected by two different viral strains at the same time. (science20.com)
  • During coinfection, different segments of each virion can recombine, thus creating a new viral strain emergence that is sometimes even more detrimental than the original parent viral strains. (science20.com)
  • Furthermore, viral strains from different species can also recombine with each other. (science20.com)
  • When two different species' influenza strains (for example pig and human) recombine, the novel viral strain that emerges potentially has a better chance of evading the immune system and persisting in the host organism than the pre-existing viral strains. (science20.com)
  • Due to the sudden and drastic antigenic shifts that are observed in rare/novel hybrid viral strains, making vaccine predictions are no longer possible and pre-designed flu shots are ineffective. (science20.com)
  • Mutations in the surface proteins allow the virus to elude some host immunity, and the numbers and locations of these mutations that confer the greatest amount of immune escape has been an important topic of study for over a decade. (wikipedia.org)
  • The result is the sudden appearance of a new virus strain to which populations may have no immunity and against which no existing vaccine may confer protection. (who.int)
  • Data from here, sets the global standard for selection of strains for flu vaccine production (4), twice per year, for immunity against these selected strains. (sciencepolicyconference.ca)
  • The Peter Doherty Centre for Immunity and Infection in Melbourne stores tens of thousands of samples of influenza collected primarily from the Asia Pacific region. (edu.au)
  • Bottom line Influenza virus somehow manages to make frequent minor changes and sudden major changes which permit temporary evasion of a population's immunity. (powershow.com)
  • This exerts pressure on the flu virus to evolve new strains capable of evading the population acquired immunity. (blogspot.com)
  • The flu vaccine usually carries three different strains, selected from the most predominant and geographically spread ones so that the resulting immunity is reactive to a wide range of flu strains. (blogspot.com)
  • Heterosubtypic immunity (HSI) is the basis of creating universal influenza vaccines. (biomedcentral.com)
  • Even though the production of influenza vaccines is well established, and the regulatory process allows for rapid strain update or exchange, it takes 4-6 months until a vaccine against a newly emerging subtype is available in sufficient quantities ( 2 , 9 ). (frontiersin.org)
  • 2,3 The capricious nature of influenza demands constant vigilance to ensure seasonal vaccines are appropriate to current strains, and supplies of these and antiviral medications are sufficient for potential need. (health.gov.au)
  • Neuraminidase inhibitors are again recommended as the first-line antiviral agents for the prevention of influenza rather than amantadine. (canada.ca)
  • In Canada, two available measures can reduce the impact of influenza: immunoprophylaxis with inactivated (killed-virus) vaccine and chemoprophylaxis or therapy with influenza-specific antiviral drugs. (canada.ca)
  • This report updates the 2004 recommendations by the Advisory Committee on Immunization Practices (ACIP) regarding the use of influenza vaccine and antiviral agents (CDC. (cdc.gov)
  • The emergence of resistance to antiviral drugs in recent years further limits the options available for the control of influenza. (distantreader.org)
  • They also underscore the challenges in vaccine strain selection, particularly regarding HA and neuraminidase substitutions derived during laboratory passage that may alter antigenic testing accuracy. (eurosurveillance.org)
  • Two classes of approved drugs against influenza A virus infections have been available for years: adamantane-based M2 ion channel blockers, which prevent acidification of the endosome and therefore release of the viral particles into the cytosol ( 10 ), and neuraminidase inhibitors, which prevent the release of newly formed viral particles from infected cells ( 11 ). (frontiersin.org)
  • Influenza virus is a pleomorphic, enveloped virus with two coat proteins on its surface, the haemagglutinin (HA) and the neuraminidase (NA). (csiropedia.csiro.au)
  • za surveillance (1), which includes clinical, virologic, and In the current global influenza surveillance system, immunologic surveillance. (cdc.gov)
  • Therefore, strong, rapid influenza surveillance systems are a priority. (health.gov.au)
  • Surveillance of the population mortality burden of influenza is difficult because few deaths have laboratory confirmation of infection. (health.gov.au)
  • For these reasons, strong influenza surveillance systems are a priority for health departments. (health.gov.au)
  • The US Centers for Disease Control and Prevention (CDC) took the approach further and established the 122 Cities Surveillance System to provide timely, prospective information of excess mortality due to influenza. (health.gov.au)
  • The WHO Collaborating Centre for Reference and Research on Influenza in Melbourne is part of the World Health Organization's (WHO) Global Influenza Surveillance and Response System. (health.gov.au)
  • The WHO Collaborating Centre for Reference and Research on Influenza in Melbourne (the Centre) is part of the World Health Organization's Global Influenza Surveillance and Response System (WHO GISRS). (health.gov.au)
  • In Switzerland, epidemiological and virological surveillance of the influenza virus (flu) is provided by the Sentinella reporting system (1986) and the mandatory reporting system. (hug.ch)
  • Scientific countermeasures include the development of diagnostic tests, a strong research effort in vaccine and therapeutic development and the constant surveillance of virus strains for structural variations. (sciencepolicyconference.ca)
  • Since the 1950s the WHO has run this global game of catch-up, and now has 143 national influenza centres in 112 countries monitoring the virus, as part of its Global Influenza Surveillance and Response System . (edu.au)
  • The influenza virus is highly active throughout New York State and has grown to high levels in several other states, and-according to surveillance data from the state Health Department-remains high in both Nassau and Suffolk counties. (yourlawyer.com)
  • For a description of influenza surveillance in the WHO European Region see below . (flutrackers.com)
  • A weekly surveillance report of seasonal influenza in the US is available at the Centers for Disease Control and Prevention's FluView . (msdmanuals.com)
  • The yearly evolution of the flu virus is closely monitored: surveillance data is collected throughout the flu season and, based on the data, a prediction is made on which strains will be most likely to reappear during the next season -- this step is important for flu vaccine design. (blogspot.com)
  • The surveillance data comes from the World Health Organization Global Influenza Surveillance Network (GISN) , a network of 136 national influenza centers scattered in 106 different countries. (blogspot.com)
  • New surveillance techniques are being developed based on this concept of antigenic distance and antigenic maps in order to help inform future vaccine selection. (blogspot.com)
  • In other words, there was a mismatch between the current virus and current vaccine. (ajc.com)
  • Influenza vaccine effectiveness can be low when there is a mismatch between vaccine strains and circulating strains," the authors said. (ajc.com)
  • That's why they hope to take on further investigations that "address whether egg-adapted mutations constitute another form of antigenic mismatch that alters vaccine effectiveness in other influenza virus seasons," the authors said. (ajc.com)
  • The name "influenza" originated in 15th century Italy, from an epidemic attributed to "influence of the stars. (cdc.gov)
  • The first documented pandemic, or worldwide epidemic, that clearly fits the description of influenza was in 1580. (cdc.gov)
  • Influenza C has not been associated with epidemic disease. (cdc.gov)
  • As early as 1932, Collins determined that excess mortality during winter months in the United States of America (USA) was a consequence of epidemic influenza and therefore could be used as an indicator for the recognition of influenza outbreaks. (health.gov.au)
  • The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold. (cdc.gov)
  • Fazekas believed that new epidemic strains could be generated in advance and this led to the Pasteur Institute manufacturing a vaccine from one of Fazekas's 'prospective' strains. (csiropedia.csiro.au)
  • Ongoing avian influenza outbreaks in animals pose risk to humans: read the situation analysis and advice to countries from the Food and Agriculture Organization of the United Nations (FAO), the World Health Organization (WHO), and the World Organisation for Animal Health (WOAH). (eurosurveillance.org)
  • Influenza B and C principally infect humans, minimizing the chance that a reassortment will change its phenotype drastically. (influenzavirusnet.com)
  • Avian influenza (H5N1) is rare in humans in developed countries. (medscape.com)
  • This property may be a consequence of the limited host range of the virus - humans and seals - which limits the generation of new strains by reassortment. (virology.ws)
  • BACKGROUND: One strategy to develop a universal influenza virus vaccine is to redirect the immune system to the highly conserved haemagglutinin stalk domain by sequentially administering vaccines expressing chimeric (c) haemagglutinins with a conserved stalk domain and divergent head domain, to which humans are naive. (bvsalud.org)
  • A separate strain emerging in South Africa has also raised concerns about the vaccines' effectiveness. (biopharmadive.com)
  • Speaking last week at the J.P. Morgan Healthcare Conference, BioNTech CEO Ugur Sahin said data from a separate study of Comirnaty's effectiveness in combating that strain were due in 10 days. (biopharmadive.com)
  • The modelling approach allows health departments to make a more objective assessment of the severity of seasonal influenza and the effectiveness of mitigation strategies. (health.gov.au)
  • During the 2014-2015 season, flu vaccine effectiveness was just 19 percent, according to the Centers for Disease Control and Prevention, and it rose to 47 percent during the 2015-2016 season. (ajc.com)
  • Influenza vaccine effectiveness continues to be challenging as influenza disproportionately affects adults 65 years and older. (flu360.com)
  • where flu changes its appearance, accumulating mutations that alter the proteins around the outside of its virion (the infectious particle of the virus). (edu.au)
  • VLPs contain no genetic information (meaning they can't transmit disease), but instead they have an outer coat full of influenza surface proteins [7]. (browntth.com)
  • Virus strains are named according to influenza virus type, the place where first isolated, the isolate number and the year of isolation as well as the nature of the two surface proteins. (csiropedia.csiro.au)
  • The reason for this is not a poor immune response, rather it is the fact that the influenza virus continues to change its coat proteins so that the new infecting variants are no longer recognised and destroyed by the immune response generated against the earlier infection. (csiropedia.csiro.au)
  • The enveloped influenza A virions have three membrane proteins (HA, NA, M2), a matrix protein (M1) just below the lipid bilayer, a ribonucleoprotein core (consisting of 8 viral RNA segments and three proteins: PA, PB1, PB2), and the NEP/NS2 protein. (virology.ws)
  • Influenza B virions have four proteins in the envelope: HA, NA, NB, and BM2. (virology.ws)
  • Complications of influenza infection include secondary bacterial pneumonia and exacerbation of underlying chronic health conditions. (cdc.gov)
  • [1-5] Aspirin and other salicylate-containing medications are contraindicated for children and adolescents with influenza-like illness, as their use during influenza infection has been associated with the development of Reye syndrome. (cdc.gov)
  • The current increase in incidence of AIV infection is most likely related to antigenic drifts occurred in field AIV strains [ 5 ]. (biomedcentral.com)
  • Initial vaccines were made from bacterial formulations as some experts believed that bacteria caused the infection (10). (sciencepolicyconference.ca)
  • The resistance to zanamivir is rare [17] , but its use is limited to patients who can actively inhale it, which often excludes young children, impaired older adults or patients with underlying airway disease [14] , that is the groups of patients most vulnerable to serious influenza infection complications. (distantreader.org)
  • The Delta variant is the prime example of strains succeeding each other, becoming progressively worse in waves of infection. (cuencahighlife.com)
  • The antibody of childhood is largely a response to the dominant antigen of the virus causing the first Type A influenza infection of the lifetime. (doctorschierling.com)
  • Influenza C virus infection does not cause typical influenza illness and is not discussed here. (msdmanuals.com)
  • The majority of these were antigenically and genetically similar to the WHO recommended reference strain for the 2014 Southern Hemisphere influenza vaccine. (health.gov.au)
  • Isolates were identified as antigenically similar to the reference strain if the test samples had a titre that was no more than 4-fold different from the titre of the homologous reference strain. (health.gov.au)
  • Time is necessary to produce a vaccine that is antigenically matched to a pandemic strain. (biomedcentral.com)
  • Here, we characterized variations in the major viral antigenic sites among contemporary RSV sequences when compared with RSVPreF3 and showed that, in older adults, RSVPreF3-AS01 broadly boosts neutralization responses against currently dominant and antigenically distant RSV strains. (bvsalud.org)
  • The antigenic components of the influenza vaccine have been updated for the 2007-2008 season. (canada.ca)
  • Due to the fast evolution of the influenza virus, the components of the influenza vaccine are changed for many flu seasons. (blogspot.com)
  • A non-live, recombinant influenza virus vaccine not requiring isolation or growth in hen's eggs was licensed in 2013. (cdc.gov)
  • With some infectious diseases like influenza, shots need to be updated annually to combat the circulating strains. (biopharmadive.com)
  • Seasonal human influenza causes about 36,000 deaths and 226,000 hospitalizations in the United States annually. (medscape.com)
  • Influenza is a highly mutable virus that causes hundreds of thousands of deaths and hospitalizations annually but also poses a persistent pandemic threat. (sabin.org)
  • Influenza A infects approximately 10% of the population in the US each year and causes approximately 35,000 deaths annually. (science20.com)
  • In the Northern Hemisphere, all persons aged 6 months or older should receive influenza vaccine annually by the end of October, if possible. (medscape.com)
  • The influenza vaccine should be given annually to everyone aged ≥ 6 months who does not have a contraindication. (msdmanuals.com)
  • Researchers produced less infectious "pseudoviruses" from the original strain identified in Wuhan, China, and the new U.K. strain, and then exposed them to the serum taken from 16 patients who were given both doses of the vaccine now called Comirnaty in clinical trials. (biopharmadive.com)
  • See Clinical Presentation for more detailed information on the signs and symptoms of pediatric influenza. (medscape.com)
  • See Clinical Presentation and Workup for more detailed information on the diagnosis of pediatric influenza. (medscape.com)
  • Symptoms are non-specific and few clinical influenza diagnoses are laboratory confirmed. (health.gov.au)
  • In addition, influenza-positive original clinical samples were directly inoculated into eggs as potential vaccine strains. (health.gov.au)
  • We compared HA gene sequences from AIVs isolated between 1994 and 2000 [ 3 ], more recent isolates (2002 to 2006) from vaccinated birds showing clinical manifestations of avian influenza, and the A/Chicken/Hidalgo/232/94 vaccine strain. (biomedcentral.com)
  • All AIVs were obtained from vaccinated birds showing clinical signs of avian influenza. (biomedcentral.com)
  • Influenza traditionally has been diagnosed on the basis of clinical criteria, but rapid diagnostic tests, which have a high degree of specificity but only moderate sensitivity, are becoming more widely used. (medscape.com)
  • This is vital as the influenza virus genome (or any virus genome) can change via antigenic drifts and shifts (5,6). (sciencepolicyconference.ca)
  • Due to the structure of its genome, HIV does not undergo reassortment, but it does recombine freely and via superinfection HIV can produce recombinant HIV strains that differ significantly from their ancestors. (influenzavirusnet.com)
  • In the alpha variant, a single amino acid mutation in the latter portion of the genome enabled the virus to replicate Orf9b mRNA to 80-fold greater amounts than in non-alpha variant samples. (cuencahighlife.com)
  • However, influenza A's most advantageous feature is its segmented genome which consists of eight different linear RNA strands. (science20.com)
  • I showed that the influenza C virus genome consists of 7 RNA segments, and demonstrated reassortment among different influenza C virus strains. (virology.ws)
  • Influenza A virus (IAV), a member of the Orthomyxoviridae family, possesses a negative strand RNA genome made up of eight gene segments. (biomedcentral.com)
  • Over 100 years ago, the 1918 influenza pandemic killed 675,000 Americans. (csis.org)
  • At least 50 million people were killed by the 1918 influenza strain. (sabin.org)
  • The 1918 influenza pandemic was the deadliest in the history of the world (9). (sciencepolicyconference.ca)
  • The coronavirus vaccine developed by Pfizer and BioNTech is as effective in laboratory testing against a fast-spreading virus variant that originated in the U.K. as it is against the original SARS-CoV-2 strain identified in China, the companies reported Wednesday . (biopharmadive.com)
  • iii Just because we are reeling from a coronavirus pandemic does not mean we are exempt from another influenza pandemic-now or in the future. (csis.org)
  • S2D14 may be a useful scaffold or tool for the design of future coronavirus vaccines, and the approaches used for the design of S2D14 may be broadly applicable to streamline vaccine discovery. (bvsalud.org)
  • Type B influenza is classified into two lineages: B/Yamagata and B/Victoria. (cdc.gov)
  • influenza virus antigenic variants emerge frequently from accumulation of point mutations in the HA protein (i.e. (cdc.gov)
  • Influenza virus undergoes rapid antigenic evolution by accumulation of mutations and through genetic reassortments of segments. (biomedcentral.com)
  • When two different strains of influenza infect the same cell simultaneously, their protein capsids and lipid envelopes are removed, exposing their RNA, which is then transcribed to mRNA. (influenzavirusnet.com)
  • Different strains of influenzavirus have different pathologic effects. (wakingupcosts.net)
  • Third, in the early 1950s, it was found that individuals had a strong tendency to possess higher antibody (Ab) titers against IAV strains they were exposed to as children than to more recently circulating strains. (doctorschierling.com)
  • The antibody-forming mechanisms have been highly conditioned by the first stimulus, so that later infections with strains of the same type successively enhance the original antibody to maintain it at the highest level at all times in that age group. (doctorschierling.com)
  • Persons 65 years of age and older, young children, pregnant women, and persons of any age with certain underlying health problems are at increased risk for complications of influenza and hospitalization. (cdc.gov)
  • Most deaths associated with influenza in industrialized countries are due to complications of underlying diseases in people with well defined risks, including age over 65 years, chronic cardiovascular, pulmonary, metabolic or renal disease, and immunosuppression. (who.int)
  • Programs should focus on those at high risk of influenza-related complications, those capable of transmitting influenza to individuals at high risk of complications, and those who provide essential community services. (canada.ca)
  • 2 years, and persons of any age who have medical conditions that place them at increased risk for complications from influenza ( 2,5--7 ). (cdc.gov)
  • According to a prospective cohort study, as many as 1 in 3 children seeking treatment in the ED for influenza-like illnesses (ILI) at the peak of flu season are at high risk of suffering severe complications. (medscape.com)
  • Of the 329 amino acid positions on HA1, 131 lie on or near the five antigenic sites (7,8). (cdc.gov)
  • The U.K. strain, called B.1.1.1.7, had 10 amino acid changes in the characteristic "spike" protein, which all of the authorized vaccines target. (biopharmadive.com)
  • In the period from 1975 to 1983, CSIRO scientists Colin Ward, Theo Dopheide, Gerry Both and Merilyn Sleigh achieved international recognition for their work on the amino acid and gene sequences of numerous influenza virus haemagglutinins. (csiropedia.csiro.au)
  • To map the neutralizing specificity, we used mutational antigenic profiling to determine how all amino-acid mutations in Env affected viral neutralization. (scitok.com)
  • Immunization is the most effective means to reduce the impact of influenza. (canada.ca)
  • Whatɰ the impact of influenza on adults 65 years and older? (flu360.com)
  • This statement contains new information on human and avian influenza epidemiology. (canada.ca)
  • To fully understand the epidemiology of viral pathogens it is useful to study their population genetics, and how the micro-evolutionary process (or phylodynamics) that is driven by mutation dynamics within cells, is manifest at higher scales (individuals, groups, populations, and landscapes) after the influences of selection, recombination, and transmission have acted. (gla.ac.uk)
  • Dr. Joseph Bresee, chief of the epidemiology and prevention branch in the CDC's influenza division, feels there is no need to embargo Tamiflu, "This certainly bears close watching," he said yesterday. (yourlawyer.com)
  • Under this scenario, the virus has the potential to kill between 10 and 35% of people infected, as did SARS-CoV and MERS-CoV, up from the 1 to 2% lethality, characteristic of the current strains. (cuencahighlife.com)
  • In order to anticipate the next flu strains, researchers need to understand how well the population is responding to the current strains. (blogspot.com)
  • WHO recommends annual immunization of at-risk persons as the best and most cost-effective strategy for reducing influenza-related morbidity and mortality. (who.int)
  • Influenza is a serious disease that seasonally causes varying but substantial morbidity and mortality. (health.gov.au)
  • Influenza-virus-mediated disease can be associated with high levels of morbidity and mortality, particularly in younger children and older adults. (mdpi.com)
  • The virus causes significant morbidity: in the US in 2008, approximately one-third of all laboratory confirmed cases of influenza were caused by influenza B (as shown on the first graph on this CDC page) . (virology.ws)
  • This study also demonstrates that molecular drifts in the HA gene lineages follow a yearly trend, suggesting gradually cumulative sequence mutations. (biomedcentral.com)
  • In 1999, sequencing of the full length haemagglutinin (HA) gene (encodes HA, a surface protein) was achieved, pioneering vaccine and drug development with HA as a target (22,23). (sciencepolicyconference.ca)
  • the gene segment had a human influenza virus origin. (scapca.org)
  • This occurs when circulating influenza strains do not match the WHO-selected strains contained in the vaccine. (flu360.com)
  • The influenza virus occurs as three types A, B and C which correspond to three genera of the family Orthomyxoviridae . (csiropedia.csiro.au)
  • Assessing the population burden of influenza is difficult. (health.gov.au)
  • Evidence from animal models shows that T cells can provide heterosubtypic protection and are crucial for immune control of influenza virus infections. (mdpi.com)
  • Vaccine developer Gritstone Oncology on Tuesday announced development of a second generation vaccine that will stimulate a stronger response from immune-fighting white blood cells that it believes can offer broader protection. (biopharmadive.com)
  • First, the adjuvant stimulates increased activation of naïve B cells, thus reducing immune interference with previous vaccine responses. (nature.com)
  • Because the human immune system has difficulty recognizing the new influenza strain, it may be highly dangerous. (influenzavirusnet.com)
  • However, their high genetic variability allows the virus to evade the host immune response and the potential protection offered by seasonal vaccines. (distantreader.org)
  • An adjuvant is a substance added to a vaccine to boost the immune response. (flu360.com)
  • The emergence of a viral strain that is capable of evading the host's immune system as well as transmits and replicates effectively, is precisely the recipe for a potential pandemic. (science20.com)
  • In the early 1970s there was considerable speculation about the way in which the influenza virus escaped immune responses and continued to cause repeated infections year after year. (csiropedia.csiro.au)
  • How "different" any two strains are is measured by a quantity called "antigenic distance," which, in layman terms, measures how well current immune responses ("animal antisera raised against the same or related strains, [3]") are able to block those strains. (blogspot.com)
  • Cellular immune responses may play an important role in HSI against influenza virus. (biomedcentral.com)
  • Influenza is an infectious viral illness. (cdc.gov)
  • Influenza C is rarely reported as a cause of human illness, probably because most cases are subclinical. (cdc.gov)
  • Of the primary care physicians (general practitioners, internists and pediatricians) participating in the Sentinella reporting system, around a half address nasopharyngeal swabs taken from some of their patients with influenza-like illness (ILI) to the National Reference Center of Influenza (NRCI). (hug.ch)
  • The protective efficacy of these inactivated vaccines was demonstrated in the 1950s. (cdc.gov)
  • Manufacturer(s) have sought approval of the vaccine(s) and provided evidence as to its safety and efficacy only when it is used in accordance with the product monographs. (canada.ca)
  • These slight differences can cause a very low vaccine efficacy rate, as seen in the 40% efficacy rate of the 2012-2013 influenza virus [3]. (browntth.com)
  • This reduced manufacturing time can enable a more accurate prediction of which influenza strains will be circulating during flu season, in turn increasing the efficacy of the vaccine. (browntth.com)
  • Therefore, the breadth of RSVPreF3-AS01-elicited neutralization responses may contribute to vaccine efficacy against contemporary RSV strains and those that may emerge in the future. (bvsalud.org)
  • 112 national influenza centres in 83 countries and four WHO collaborating centres for reference and research on influenza.1 National centres transfer representative viral isolates to the collaborating centres for immediate strain identification. (who.int)
  • Virus samples are submitted to WHO collaborating centres by WHO National Influenza Centres and other hospital and regional laboratories. (health.gov.au)