Most 10 Yr Olds w/ Negative/Unknown Histories of Chickenpox Immune
This article finds that nearly 2/3 of children in whom there was no history of chickenpox infection are immune to the disease. The authors estimate that, based on this information, 8.5% of children would need the vaccine. This seems to weigh heavily against the push for the varicella vaccine. Couple this with the very low incidence of severe complications with varicella infection and the argument for really starts to fall apart. Unfortunately, given the power of advertising, unsuspecting consumers listening to ads would assume their child is at high risk of both infection and subsequent hospitalization and/or death.
Pediatr Infect Dis J 2001;20:1087-1088 Contrary to widely held beliefs, most 10-year-old children with negative or unknown chickenpox histories are actually immune to varicella, according to a report by Canadian investigators. Dr. Bernard Duval, from Laval University in Quebec, and colleagues assessed the age-specific incidence of varicella among 2227 fourth grade students. A subset of children with negative or unknown chickenpox histories were tested for anti-varicella antibodies. The study was performed to determine the proportion of children that would need to be vaccinated in a catch-up program. The reported cumulative incidence of chickenpox at 10 years of age was 92%, the authors note. Furthermore, about half of the children developed chickenpox before entering kindergarten. Of the children with negative or unknown varicella histories, 63% had antibodies against the virus. Children with an unknown history were significantly more likely than those with a negative history to harbor anti-varicella antibodies (p = 0.002). In addition, children whose history was obtained by self-administered questionnaire rather than by a study nurse were more likely to demonstrate such antibodies (p = 0.023). If vaccination was based on the absence of a positive history of varicella, 8.4% of 10-year-old children would require vaccination, the researchers note. However, the current findings indicate that nearly two thirds of children without a positive history are actually immune. Prevaccination testing could identify children who are immune, but such testing could be difficult to implement and might reduce vaccine coverage. Follow-up telephone interviews with parents who report negative or unknown histories for their children may help identify children who are actually immune