Vaccine Extraimmunization—Too Much of a Good Thing?

The article by Feikema and colleagues¹ in this issue of THE JOURNAL suggests that extraimmunization of children occurs considerably more often than previously appreciated. Using data from the National Immunization Survey, Feikema et al examined the immunization histories of more than 22,000 children aged between 19 and 35 months. The National Immunization Survey used 2 steps to collect information: in the first, parents with eligible children were identified, and in the second, the child's immunization records were obtained from their health care provider. The proportion of children who received extra immunization doses ranged, by individual vaccine, from 2.5% for measles-containing vaccine to more than 14% for poliovirus vaccine. Taken together, up to 21% of all children were reported to have received at least 1 extra immunization before their third birthday. In the multivariate analysis of risk factors for extraimmunization, Feikema and colleagues found that children with more than 1 health care provider were almost 3 times more likely to be extraimmunized compared with children with a single provider. Extraimmunization not only wastes vaccine, money, and labor, but unnecessary doses add to a child's stress and discomfort, increase the risk for adverse events following vaccination, and may lead to confusion among parents and health care providers about what vaccines have, and have not, actually been administered. The authors conclude that more attention needs to be focused on the problem of duplicate immunization.