Predictive value of a self-reported history of varicella infection in determining immunity in adults.
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The recent introduction of a vaccine for varicella has raised questions about whether, for adults, a patient's history of varicella infection is useful in determining if vaccination is necessary. We report findings on 184 family medicine patients aged 18 to 65 years who were asked if they had a history of varicella infection and were subsequently tested for varicella antibodies. A history of infection was positive for 114 (62%) of the participants and negative or uncertain for 70 (38%). All 114 subjects who reported a varicella infection history were immune. All 4 subjects who were not immune reported an uncertain or negative infection history. Except for people who are at increased risk of varicella infection or complications from infection, serologic testing may not be required for adults in the general population who have a history of varicella infection. (+info)
Genetic profile of an Oka varicella vaccine virus variant isolated from an infant with zoster.
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Varicella virus vaccine strain Oka (V-Oka) has in rare cases caused zoster in vaccinated people. Despite broad usage of V-Oka, little is known about varicella-zoster virus genomic sequence variation of strains in vaccine and isolates from patients with vaccine adverse events. Direct sequencing of 20 regions of V-Oka-GSK was compared to the sequences of the original V-Oka-Biken, GlaxoSmithKline Oka vaccine (V-Oka-GSK), and Oka-parental (P-Oka) strains. We analyzed single nucleotide polymorphisms (SNP) differentiating the Oka parental and Oka vaccine strains identified in open reading frames (ORFs) 6, 9A, 10, 21, 31, 39, 50, 51, 52, 54, 55, and 59 and eight base substitutions within ORF 62. Sixteen of these SNP impose an amino acid change in the corresponding gene product. The genotypic analysis revealed that (i) both V-Oka-GSK and V-Oka-Biken comprise mixtures of strains represented in variable proportion from lot to lot; (ii) V-Oka-GSK/zoster isolated from the zoster patient had six wild-type SNP in ORF 9A, 10, 21, 52, 55, and 62 (mutation 108838); (iii) none of the six revertant SNP would reliably discriminate Oka vaccine from the wild type; and (iv) the genomic variation found in V-Oka/zoster might be associated with changes in the biological behavior of the virus. Further studies will be needed to identify potential virulence factors in variant vaccine strains. (+info)
Seroepidemiology of varicella-zoster virus antibodies among health-care workers and day-care-centre workers.
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Inclusion of live varicella vaccine in the routine occupational health vaccination schedule requires knowledge of the natural immunity to varicella zoster virus (VZV) among high-risk occupations. This study aims were to evaluate VZV antibody positivity among health-care workers (HCWs) and day-care-centre workers (DCWs) and to assess its association with potential risk factors. Three groups of workers were tested for VZV antibody positivity: hospitals and community clinic HCWs (n = 335), DCWs (n = 117) and blue-collar workers as controls (n = 121). The total VZV antibody positivity was 94.4%. There was no significant difference in VZV antibody positivity among study groups. DCWs had the lowest VZV seroprevalence (90.9%, 95% CI 85.7-96.1) and controls the highest (96.6%, 95% CI 93.2-99.9). This high VZV antibody positivity suggests that no special occupational measures are indicated in health-care or day-care occupational settings in Israel. On-going monitoring of the natural immunity to VZV is necessary to detect trends over time. (+info)
Preventing varicella-zoster disease.
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Varicella-zoster virus (VZV), the cause of chickenpox and shingles, is a pathogen in retreat following the introduction of mass vaccination in the United States in 1995. The live attenuated Oka vaccine, which is safe and immunogenic, gives good protection against both varicella and zoster in the short to medium term. It has undoubtedly been highly effective to date in reducing all forms of varicella, especially severe disease. However, the huge pool of latent wild-type virus in the population represents a continuing threat. Both the biology and the epidemiology of VZV disease suggest that new vaccination strategies will be required over time. (+info)
Decline in mortality due to varicella after implementation of varicella vaccination in the United States.
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BACKGROUND: Varicella disease has been preventable in the United States since 1995. Starting in 1999, active and passive surveillance data showed sharp decreases in varicella disease. We reviewed national death records to assess the effect of the vaccination program on mortality associated with varicella. METHODS: Data on deaths for which varicella was listed as an underlying or contributing cause were obtained from National Center for Health Statistics Multiple Cause-of-Death Mortality Data for 1990 through 2001. We calculated the numbers and rates of death due to varicella according to age, sex, race, ethnic background, and birthplace. RESULTS: The rate of death due to varicella fluctuated from 1990 through 1998 and then declined sharply. For the interval from 1990 through 1994, the average number of varicella-related deaths was 145 per year (varicella was listed as the underlying cause in 105 deaths and as a contributing cause in 40); it then declined to 66 per year during 1999 through 2001. For deaths for which varicella was listed as the underlying cause, age-adjusted mortality rates dropped by 66 percent, from an average of 0.41 death per 1 million population during 1990 through 1994 to 0.14 during 1999 through 2001 (P<0.001). This decline was observed in all age groups under 50 years, with the greatest reduction (92 percent) among children 1 to 4 years of age. In addition, by the period from 1999 through 2001, the average rates of mortality due to varicella among all racial and ethnic groups were below 0.15 per 1 million population, as compared with rates ranging from 0.37 per 1 million for whites to 0.66 per 1 million for other races in the period from 1990 through 1994. CONCLUSIONS: The program of universal childhood vaccination against varicella in the United States has resulted in a sharp decline in the rate of death due to varicella. (+info)
Barriers to adolescent immunization: a survey of family physicians and pediatricians.
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BACKGROUND: Although early childhood vaccination rates have increased, many adolescents are not up to date on recommended vaccinations. We assessed attitudes and practices of family physicians and pediatricians regarding adolescent vaccination to identify provider-level barriers that may contribute to low immunization rates. METHODS: A 94-item self-report questionnaire was mailed to 400 physicians contracted with a managed care organization. Physicians were queried about demographic characteristics, source of vaccine recommendations, adolescent immunization practices, barriers to immunizing adolescents, and use of reminder/recall systems. RESULTS: Response rate was 59%. Most respondents reported routinely recommending vaccines for tetanus and diphtheria toxoids (98%), Hepatitis B (90%), and measles, mumps, and rubella (84%), whereas 60% routinely recommended varicella vaccine. Physicians reported that they were more likely to assess immunization status, administer indicated immunizations, and schedule return immunization visits to younger adolescents (11 to 13 years old) than to older adolescents (14 to 18 and 19 to 21 years old). CONCLUSION: Most respondents reported recommending the appropriate vaccinations during preventive health visits; however, older adolescents were least likely to be targeted for immunization assessment and administration of all recommended vaccines. (+info)
Varicella-related deaths--United States, January 2003-June 2004.
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During 2003 and the first half of 2004, CDC received reports of eight varicella-related deaths. The age of the decedents ranged from 1 to 40 years. Six of the eight deaths occurred among children and adolescents aged <20 years. The cases were reported from Arizona (two), Maryland (two), Arkansas (one), New Hampshire (one), Ohio (one), and New York City (one). Six deaths occurred in unvaccinated persons. Vaccination status of the remaining two persons could not be determined. This report describes clinical data for three of the fatal varicella cases in children, reported from Arizona, Arkansas, and New York City; all three patients were susceptible and unvaccinated, but otherwise healthy. The three other children and adolescents, not described in detail in this report, were immunocompromised as a result of at least one preexisting condition. The findings in this report underscore 1) the importance of timely routine vaccination of children aged 12--18 months and catch-up vaccination of older susceptible children and adolescents according to current recommendations and 2) the need for timely and complete national varicella death surveillance. (+info)
Varicella surveillance in public elementary schools--Multnomah County, Oregon, 2002-2004.
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Varicella vaccination of school-aged children reduces the number of varicella cases and lost days of school. In 1996, the Advisory Committee on Immunization Practices (ACIP) recommended routine vaccination of all children aged 12-18 months, catch-up vaccination of all susceptible children before age 13 years, and vaccination of susceptible persons who have close contact with persons at high risk for serious complications and susceptible persons at high risk for exposure. In 1999, ACIP updated these recommendations to include vaccination requirements for child care and school entry. Since 2000, in accordance with ACIP recommendations, varicella vaccination requirements have been phased in for Oregon children who have not had varicella before starting out-of-home child care, kindergarten, or seventh grade; elementary school children will be fully covered by school year (SY) 2006-07. To monitor changes in varicella incidence, Oregon Health Services (OHS) and Multnomah Education Service District (MESD) started routine, individual, case-based varicella surveillance in Multnomah County public elementary schools (kindergarten through 5th grade) beginning SY 2002-03. This report describes the surveillance system, the incidence of varicella during SY 2002-03 and SY 2003-04, and the results of active surveillance for unidentified cases during SY 2002-03. The findings indicate that the number of varicella cases has decreased in Oregon and that establishing public elementary school-based varicella surveillance is feasible and useful. (+info)