SEROLOGICAL STUDY ON IMMUNITY TO MEASLES AND MUMPS IN NORTHERN GREEK CHILDREN

INTRODUCTION: Routine immunization against measles and mumps has substantially reduced the number of these infections annually. However, outbreaks have been reported recently, even in highly vaccinated populations. OBJECTIVE: Our goal was to determine the levels of serum antibodies against measles and mumps in a population of children who were vaccinated against measles-mumps-rubella (MMR). METHODS: The study population consisted of 260 healthy children (aged 15 months to 14.5 years) who were separated into 2 groups according to the number of MMR vaccine doses previously administered: groups A (1 dose) and B (2 doses). Immunoglobulin G (IgG) and IgM antibody levels for measles and mumps were determined in blood serum by the enzyme-linked immunosorbent assay (Genzyme Virotech, Russelsheim, Germany) semiquantitive method. RESULTS: Groups A and B consisted of 53 children aged 15 months to 8 years and 207 children aged 5 to 14.5 years old, respectively. A majority (93.08%) of the children were protected against measles. Group A and B protection rates were similar (92.27% and 96.23%, respectively). Although most of the children were protected against mumps, the total protection rate was significantly less (81.92%) ( P < .01). The protection rate against mumps in group A was significantly lower than that in group B (67.92% vs 85.51%; P < .03). CONCLUSIONS: Our results indicate high protection rates against measles conferred even by a single dose of the MMR vaccine. A respected percentage of the children were found to be susceptible to mumps even after completion of a 2-dose immunization schedule. Primary vaccine failure may be implicated as a cause of recent mumps outbreaks, but additional studies are needed. Submitted by Katerina Haidopoulou