IMMUNITY TO MEASLES BEFORE AND AFTER MMR BOOSTER OR PRIMARY VACCINATION AT 12 YEARS OF AGE IN THE FIRST-GENERATION OFFERED THE 2-DOSE IMMUNIZATION PROGRAM

In 1982, a 2-dose regimen was introduced in Sweden for the combined va ccination against measles, mumps and rubella (MMR) in children aged 18 months and 12 years. In 1993, blood samples from 378 12-year-old chil dren, i.e. the first age-group receiving a MMR booster, mere collected prior to and 2 months after the vaccination. 82% had a certificate of a previous measles (M) or MMR IR vaccination (group I). The remainder was classified as children with 'no documentation' (group II). In gro up I, 5 (1.5%) lacked demonstrable antibodies to measles prior to the booster; in,group II this figure was 39%. The pre-booster antibody pat tern was similar in M vaccinees and MMR vaccinees. After the vaccinati on, 1 of the 378 children was seronegative. In both groups? children w ith low pre-vaccination levels responded with a titre rise, in accorda nce with a similar study 6 years earlier.