Early Two-Dose Measles Vaccination Deemed Useful in Endemic Areas

WESTPORT, CT (Reuters Health) Dec 04 - An early two-dose measles vaccination schedule can improve vaccination coverage in areas at high risk of measles among infants, according to an analysis of the schedule's impact in Dade County, Florida.

"Our findings...support the Advisory Committee on Immunization Practices recommendation to use this schedule when the risk of measles is high among infants," Dr. Sonja S. Hutchins, of the Centers for Disease Control and Prevention in Atlanta, and a multicenter team conclude in the December 1st issue of the American Journal of Epidemiology.

The investigators examined the impact of vaccinating infants at 6 months and again at 12-15 months by assessing coverage, humoral immunity and clinical protection before and after the schedule was first instituted in Dade County to control a large measles epidemic in 1986 to 1987.

Vaccination coverage among 2-year-olds increased from 75% before the implementation of the early schedule to 94% in 1996. Seroprevalence of plaque reduction neutralization antibody among children age 4 to 6 years in 1995 was similar between children who received the early two-dose vaccination schedule and those who received a single dose of the vaccine at or after 12 months of age. And clinical protection was high in both groups, at 99.5% and 99.7%, respectively.

"Our study suggests that an early two-dose measles vaccination schedule in high-risk areas of Dade County was effective in preventing and controlling measles in the community," Dr. Hutchins and others say in the report. "Implementation of this schedule was associated with a reduction in measles morbidity and mortality," they add, with no reported increase in vaccine side effects. Measles cases also shifted from younger to older children after implementation of the schedule, and endemic transmission ended after 1993.

The team concludes that the early two-dose measles vaccination schedule is a safe and effective way to improve vaccine coverage and reduce measles morbidity and mortality in areas at high risk of measles in infants.

Am J Epidemiol 2001;154:1064-1071.