Mass vaccination programme aimed at eradicating measles, mumps, and rubella in Sweden: first experience.

General vaccination with a combined measles, mumps, and rubella vaccine was introduced in Sweden in 1982. The immunisation schedule comprises two vaccine injections, given at 18 months and 12 years of age, respectively. A controlled field study was carried out in 150 children aged 18 months using two different batches of the vaccine. Seroconversion was seen in 96% against measles, 93% against mumps, and 99% against rubella--the same rates with both vaccine lots. Nevertheless, a difference was noted between the two batches with respect to postvaccination reactions. Fever and rash were recorded mainly five to 12 days after vaccination. Moderate fever (38.5-39.4 degrees C) was observed in 22 children, high fever (greater than or equal to 39.5 degrees C) in 33, and rash in 35. Preliminary results obtained by follow up of routinely vaccinated schoolchildren aged 12 indicated considerably lower rates of fever and rash during the postvaccination period, occurring in 3-10% of cases only. These findings show that complete eradication of measles, mumps, and rubella in Sweden is entirely practicable by the mass vaccination programme and that side effects of vaccination are likely to be few and mild.