5-YEAR FOLLOW-UP OF MORBIDITY AND MORTALITY AMONG RECIPIENTS OF HIGH-TITER MEASLES-VACCINES IN SENEGAL

At 3-5 years of age, female recipients of Edmonston-Zagreb high-titre (EZ-HT) and Schwarz high-titre (SW-HT) measles vaccine had lower survi val rates than female recipients of Schwarz standard measles vaccine ( SW-STD) in Guinea-Bissau, Senegal and Haiti. In senegal, the children who received high-titre vaccines have now been followed to the age of 5-7 years to determine whether the difference in mortality persisted, and whether differences in vaccine efficacy were apparent. At this age there was no difference in mortality between female recipients of hig h-titre and standard titre measles vaccines. There was no indication t hat high-titre EZ-HT vaccine at 5 months (EZ-HT, 5m) provided suboptim al protection, as vaccine efficacy after exposure was 97% and 95%, res pectively, for EZ-HT, 5m and SW-STD, 10m vaccines, whereas SW-HT, 5m v accine had an efficacy of 81%. The difference in mortality between rec ipients of high-titre vaccines and SW-STD observed in several studies during the first few years after vaccination may be explained by non-s pecific beneficial effects of the standard measles vaccine rather than a harmful effect of the high-titre vaccines.