[The development and duration of immunity in children vaccinated against measles with the Edmonston-Zagreb vaccine].

After routine measles-rubella-mumps (MRM) vaccine, seroconversion rate for measles heminhibiting (HI) antibodies in a group of 161 children was determined. Of the 154 children who had no HI antibodies in the first serum sample, 153 (99.3%) developed these antibodies in titres greater than or equal to 1:4 and 148 (96.1%) in titres greater than or equal to 1:8 at 6 weeks postvaccination. These results are in concord with the WHO standards. Another study was designed to evaluate persistence of HI antibodies to measles in a group of 123 children who were given MRM vaccine 1-6 years earlier. No significant decrease in HI antibody titers was recorded. It is concluded that immunity acquired through vaccination with the Edmonston-Zagreb measles virus strain in children aged 12 months to 3 years is satisfactory and that it does not decrease at least up to 6 years following vaccination.