THE ELIMINATION OF INDIGENOUS MEASLES, MUMPS, AND RUBELLA FROM FINLAND BY A 12-YEAR, 2-DOSE VACCINATION PROGRAM

Background. In the 1970s measles, mumps, and rubella were rampant in F inland, and rates of immunization were inadequate. in 1982 a comprehen sive national vaccination program began in which two doses of a combin ed live-virus vaccine were used. Methods. Public health nurses at 1036 child health centers administered the vaccine to children at 14 to 18 months of age and again at 6 years, and also to selected groups of ol der children and young adults. Vaccination was voluntary and free of c harge. In follow-up studies, we focused on rates of vaccination, reaso ns for noncompliance, adverse reactions, immunogenicity, persistence o f antibody, and incidence of the three diseases. Since 1987, paired se rum samples have been collected from all patients with suspected cases of measles, mumps, or rubella. Results. Over a period of 12 years, 1. 5 million of the 5 million people in Finland were vaccinated. Coverage now exceeds 95 percent. The vaccine was efficient and safe, even in t hose with a history of severe allergy. No deaths or persistent sequela e were attributable to vaccination. The most frequent complication req uiring hospitalization was acute thrombocytopenic purpura, which occur red at a rate of 3.3 per 100,000 vaccinated persons. The 99 percent de crease in the incidence of the three diseases was accompanied by an in creasing rate of false positive clinical diagnoses. In 655 vaccinated patients with clinically diagnosed disease, serologic studies confirme d the presence of measles in only 0.8 percent, mumps in 2.0 percent, a nd rubella in 1.2 percent. The few localized outbreaks were confined t o patients in the partially vaccinated age groups. There are now fewer than 30 sporadic cases of each of the three diseases per year,and tho se are probably imported. Conclusions. Over a 12-year period, an immun ization program using two doses of combined live-virus vaccine has eli minated indigenous measles, mumps, and rubella from Finland. Serologic studies show that most reported sporadic cases are now due to other c auses, but a continued high rate of vaccination coverage is essential to prevent outbreaks resulting from exposure to imported disease.