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Studies from Columbia University, Division of Pediatric Infectious Diseases update current data on chickenpox vaccines
May 5th, 2008
2008 MAY 5 -- Researchers detail in 'Primary vaccine failure after 1 dose of varicella vaccine in healthy children,' new data in chickenpox. "Universal immunization of young children with 1 dose of varicella vaccine was recommended in the United States in 1995, and it has significantly decreased the incidence of chickenpox. Outbreaks of varicella, however, are reported among vaccinated children," investigators in the United States report. "Although vaccine effectiveness has usually been 85%, rates as low as 44% have been observed. Whether this is from primary or secondary vaccine failure-or both-is unclear. We tested serum samples from 148 healthy children immunized against varicella in New York, Tennessee, and California to determine their seroconversion rates, before and after 1 dose of Merck/Oka varicella vaccine. The median age at vaccination was 12.5 months; postvaccination serum samples were obtained on average 4 months later. Serum was tested for antibodies against varicella-zoster virus (VZV) by use of the previously validated sensitive and specific fluorescent antibody to membrane antigen (FAMA) assay. Of 148 healthy child vaccinees, 113 (76%) seroconverted, and 24% had no detectable VZV FAMA antibodies. Our data contrast with reported seroconversion rates of 86%-96% by other VZV antibody tests and suggest that many cases of varicella in immunized children are due to primary vaccine failure," wrote D.E. Michalik and colleagues, Columbia University, Division of Pediatric Infectious Diseases. The researchers concluded: "A second dose of varicella vaccine is expected to increase seroconversion rates and vaccine effectiveness." Michalik and colleagues published their study in the Journal of Infectious Diseases (Primary vaccine failure after 1 dose of varicella vaccine in healthy children. Journal of Infectious Diseases, 2008;197(7):944-9). For additional information, contact D.E. Michalik, Columbia University Medical Center, Division of Pediatric Infectious Diseases, New York, New York 10032 USA.. The publisher of the Journal of Infectious Diseases can be contacted at: University Chicago Press, 1427 E 60th St., Chicago, IL 60637-2954, USA. Keywords: United States, New York, Chickenpox Vaccines, Biotechnology, Chickenpox, Immunization, Merck & Company Inc., Pediatric, Pharmaceutical Business, Pharmaceutical Company, Vaccination, Vaccines, Varicella-Zoster Virus, Virology. This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2008, Biotech Business Week via NewsRx.com.
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