Magnitude of interference after diphtheria-tetanus toxoids-acellular pertussis/Haemophilus influenzae type b capsular polysaccharide-tetanus vaccination is related to the number of doses administered.
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We compared the antibody response to Haemophilus influenzae type b capsular polysaccharide (PRP) after 1, 2, or 3 doses of a diphtheria-tetanus toxoids-acellular pertussis (DTaP) vaccine combined with a PRP-tetanus conjugate (PRP-T) vaccine, followed by separate injections of DTaP and PRP-T vaccines for the last 1 or 2 doses. Healthy infants were recruited from pediatric practices and were immunized according to recommended schedules. A significant decrease in the mean anti-PRP (from 5.25 to 2.68 microg/mL) and anti-tetanus toxoid antibody responses (from 0.13 to 0.09 Eq/mL) was observed as the number of doses of the DTaP/PRP-T combination vaccine increased (P<.02 and P=.01, respectively). In contrast, the mean anti-diphtheria toxoid antibody response increased with increasing numbers of DTaP/PRP-T doses (P=.0001). The effects of interference were not eliminated by the completion of the primary series with 1 or 2 doses of the DTaP and PRP-T vaccines given separately. (+info)
Antibody status to poliomyelitis, measles, rubella, diphtheria and tetanus, Ontario, 1969-70: deficiencies discovered and remedies required.
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A serologic survey was made in 15 health unit areas, testing some 5000 individuals in the age groups 4 to 6, 11 to 13, 15 to 17 and 23 to 45 years. Two types of serious deficiency were found. Only 65% of children 4 to 6 years old had antibodies to all three types of poliovirus, the antibodies being due almost entirely to immunization with Salk vaccine. Even in children who had had six or more doses only 74% had antibodies to the three types. The high percentage of students 11 to 13 and 15 to 17 years old with poliovirus antibodies can be attributed largely to natural infection and to Sabin vaccine in the mass campaign of 1962, as well as to Salk vaccine. In children who had received Sabin vaccine as well as Salk vaccine a very high level of immunity was found. The immunity of the school-age population will decline to an insufficient level unless Sabin vaccine is used after immunization with Salk vaccine. Of children 4 to 6 years old 18% had no diphtheria antitoxin and 6% had no tetanus antitoxin. Even in those who had had six or more doses of the antigens 5% had no diphtheria antitoxin and 1 to 2% had no tetanus antitoxin. This apparently refractory state is probably due to the use of unadsorbed toxoids, and it is clear that adsorbed toxoids should be used. In the adults, diphtheria antitoxin was found in only 55% and tetanus antitoxin in only 38%. (+info)
Immunoglobulin a as a serological marker for the (silent) circulation of poliovirus in an inactivated poliovirus-vaccinated population.
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Poliovirus-specific immunoglobulin A (IgA) is detected after infection with wild-type virus or vaccination with live attenuated oral poliovirus (OPV) but not after vaccination with inactivated poliovirus (IPV). We examined whether the presence of IgA in serum can be used as a marker for poliovirus circulation in IPV-vaccinated populations in The Netherlands. In seronegative persons challenged with OPV, the sensitivity of this marker was 76%-86%. Results from a serosurvey showed a high seroprevalence (63%-73%) of IgA in the population born before vaccination was introduced in The Netherlands, which reflects natural exposure. The start of the vaccination program in 1957 corresponded to a reduction in the IgA seroprevalence in both vaccinated (2.1%-4.5%) and nonvaccinated groups (8.3%-11.7%). The presence of IgA-positive persons in the population could largely be explained by the occurrence of episodes of proven poliovirus circulation. We propose to use the detection of poliovirus-specific IgA as a tool to monitor virus circulation in IPV-vaccinated and nonvaccinated populations, to aid the poliovirus eradication process. (+info)
Prevalence of vaccine-derived polioviruses in the environment.
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A survey of poliovirus in river and sewage water was conducted from October 1993 to September 1995 in Toyama Prefecture, Japan. In this study, 25 isolates differentiated as type 2 vaccine-derived polioviruses (VDPVs) were characterized using mutant analysis by PCR and restriction-enzyme cleavage (MAPREC) to estimate the ratio of 481-G revertants correlated to neurovirulence in a virus population. Of these isolates, 23 (92%) comprised between 44 and 96% 481-G revertants by MAPREC. The other two isolates had revertant percentages close to the 0.6% of the attenuated reference strain. It was presumed that these 23 isolates would be variant with potential neurovirulence by MAPREC analysis. Of the 23 isolates, three were isolated from river water. Moreover, our results by MAPREC showed that type 2 poliovirus was phenotypically more variable than type 1 (69%) or type 3 (55%), as determined in previous studies. The prevalence of virulent-type VDPVs in river and sewage water suggested that the oral poliovaccine itself had led to wide environmental pollution in nature. To terminate the cycle of virus transmission in nature, the ecology of VDPVs should be studied further. A hygiene programme, inactivated poliovirus vaccine immunization and well-maintained herd immunity may play key roles in reducing the potential risk of infection by virulent VDPVs. (+info)
Effect of Pentavac and measles-mumps-rubella (MMR) vaccination on the intestine.
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BACKGROUND: The safety of infant vaccination has been questioned in recent years. In particular it has been suggested that the measles, mumps, and rubella (MMR) vaccination leads to brain damage manifesting as autism consequent to the development of an "enterocolitis" in the immediate post-vaccination period. AIM: To assess if MMR vaccination is associated with subclinical intestinal inflammation, which is central to the autistic "enterocolitis" theory. METHODS: We studied 109/58 infants, before and two and four weeks after immunisation with Pentavac and MMR vaccines, for the presence of intestinal inflammation (faecal calprotectin). RESULTS: Neither vaccination was associated with any significant increase in faecal calprotectin concentrations. CONCLUSIONS: The failure of the MMR vaccination to cause an intestinal inflammatory response provides evidence against the proposed gut-brain interaction that is central to the autistic "enterocolitis" hypothesis. (+info)
Characterization of a recombinant type 3/type 2 poliovirus isolated from a healthy vaccinee and containing a chimeric capsid protein VP1.
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A Sabin 3/Sabin 2/Sabin 3 (S3/2/3) intertypic recombinant poliovirus was isolated from a faecal specimen from a 2-year-old healthy boy approximately 12 weeks after administration of oral poliovirus vaccine. The first recombination junction was in the genomic region encoding the VP1 capsid protein between nucleotide positions 3274 and 3285 (numbering according to Sabin 3) and the second was in the RNA polymerase region (nucleotide positions 6824 and 6825). The recombination had introduced six Sabin 2-derived amino acids into the Sabin 3 capsid environment in the carboxyl terminus of VP1. The complete genome of the recombinant virus differed from corresponding parental Sabin strains at 33 nucleotide positions, nine of them resulting in an amino acid substitution. Four substitutions were in the capsid proteins and five were in the region encoding the non-structural proteins. One amino acid was changed in the antigenic site 2B and two in site 3B. In addition, the whole antigenic site 3A was replaced by Sabin 2-specific amino acids, but the antigenic characteristics of the S3/2/3 did not show type 2-specific features. Neutralizing antibody titres in sera from Finnish children immunized with the inactivated poliovirus vaccine were not lower against the recombinant virus than against Sabin 3. Our results suggest that the chimeric virus was most likely generated by recombination events in the vaccinee, rather than representing progeny of circulating vaccine-derived virus. (+info)
FDA licensure of diphtheria and tetanus toxoids and acellular pertussis adsorbed, hepatitis B (recombinant), and poliovirus vaccine combined, (PEDIARIX) for use in infants.
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On December 13, 2002, the U.S. Food and Drug Administration (FDA) licensed a combined diphtheria and tetanus toxoids and acellular pertussis adsorbed (DTaP), hepatitis B (HepB) (recombinant) and inactivated poliovirus vaccine (IPV), DTaP-HepB-IPV (PEDIARIX, SmithKline Beecham Biologicals, Rixensart, Belgium) for use in infants ages 2, 4, and 6 months. All components in the combined vaccine are recommended for routine use by the Advisory Committee on Immunization Practices (ACIP), the Committee on Infectious Diseases of the American Academy of Pediatrics, and the American Academy of Family Physicians. Combination vaccines decrease the number of vaccine injections. (+info)
Characterization of formaldehyde-inactivated poliovirus preparations made from live-attenuated strains.
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Formaldehyde-inactivated virus samples from type 1 poliovirus live-attenuated strains were prepared in the laboratory. The effect of treatment with formaldehyde on virus infectivity and immunogenicity in mice was investigated and the results compared with those from Mahoney wild-type poliovirus strain, the common type 1 component in commercial inactivated polio vaccines (IPV). Differences in the potency and specificity between these experimental vaccines were identified in both normal mice and transgenic mice expressing the human poliovirus receptor. The possible advantages/disadvantages of using live-attenuated strains for IPV production are discussed in the context of the global polio eradication initiative. A novel transgenic mouse model to study in vivo the immune protection induced by IPV preparations is described. (+info)