Rubella immunity and morbidity: effects of vaccination in Finland.

The occurrence of rubella antibodies and frequency of virologically proven rubella infections in different age groups were analyzed in a large serum material (about 60,000 sera) collected both before and after the start of nationwide vaccination of children against measles, mumps and rubella in Finland in 1982. The combined live vaccine significantly raised the rubella immunity of children and shifted rubella infections to older ages. In 1986, 91-98% immunity was found in the 2-10-year-old children so far covered by the vaccination programme; no rubella cases were diagnosed in this age group. We also demonstrated that another rubella vaccine given to about 60% of 13-year-old girls since 1975 both raised the immunity and reduced the occurrence of rubella in the vaccinated population. It is concluded that the rubella vaccinations, especially the combined vaccine given to small children, are effective, although the total number of reported rubella cases in the whole population did not decrease significantly during the study period.