SYNOPSIS
Repeated influenza vaccination at a young age substantially increases the risk of influenza at older ages.
TITLE
Repeated influenza vaccination of healthy children and adults: borrow now, pay later?
CITATION
Carrat F, Lavenu A, Cauchemez S, Deleger S. Repeated influenza vaccination of healthy children and adults: borrow now, pay later? Epidemiology & Infection 2006;134(1):63-70.
SUMMARY
This study shows that repeated influenza vaccination at younger ages may double the risk of influenza in the elderly. The study suggests that the “possible benefits of vaccinating children after 5 years of age, and otherwise healthy adults—particularly over a long period and mainly for economic reasons—could be outweighed by severe clinical consequences and increased costs in the elderly.” Moreover, the findings are “solely due to differences between vaccine-induced immunity and naturally acquired immunity.” Unlike vaccination, naturally acquired immunity can provide long-lasting protection against subsequent infection by the same viral subtype.