Optimum age for measles immunization in Romania.

From 1979 to 1985 a serological survey was carried out to evaluate the opportunity to start measles vaccination at the age of 9 months. The following aspects were investigated: the persistence of maternal measles antibodies in 188 infants aged 1-8 months: such antibodies could not be detected over 7 months of age; the antibody response to measles vaccination in 181 infants vaccinated at the age of 9-11 months versus 291 children vaccinated when aged more than 12 months: no significant differences were found between the two groups; the age-specific persistence of vaccine-induced hemagglutination-inhibiting antibodies during the 1-4 years following vaccination: no significant difference was found in terms of the children's age upon vaccination. The results lend support to the recommendation to consider 9 months as a satisfactory age to initiate measles immunization in Romania.