An Evaluation of Measles Revaccination Among School-entry-aged Children

Abstract

A two dose measles vaccination schedule is recommended routinely for all school-entry-aged children. We evaluated this recommendation by determining both measles antibody seroprevalence and the response to revaccination in seronegative children in this age group. Children 4 to 6 years of age who had received a single dose of measles vaccine between the ages of 15 to 17 months were tested for measles antibody by using enzyme-linked immunosorbent assay (ELISA) microneutralization technique. Seronegative children were revaccinated and again tested for measles antibody (immunoglobulin M [IgM] and neutralizing). Of 679 children tested, 37 (5.4%) were seronegative. Seronegativity was not significantly associated with age, sex, race, age at initial vaccination, time since vaccination, or maternal year of birth. However, children mothers with a college degree were 12 times more likely to be seronegative than children of mothers who never attended college (P < .01). Of the 37 seronegative children, 36 seroconverted after revaccination--33 producing IgM measles antibody, suggestive of a primary immune response. The cost per seroconversion would have been an estimated $415 if all 679 children had been revaccinated. Revaccination reduces the pool of children who are susceptible to measles. Although the cost per seroconversion is high, a two-dose schedule should reduce the substantial costs of controlling measles out breaks by reducing the number of outbreaks.