Antibodies against diseases of childhood have been determined in fall 1977 taking bloodsamples of 430 15-year old students. Immunity was widespread for measles (96%), chickenpox (93%), mumps (90%) whereas 27% did not have antibodies against rubella. The level of vaccination (measles, mumps, rubella) is increasing fast in younger children. The possibility of being infected by a wild virus will be low in the future for those who have not been vaccinated. Antibodies against Cytomegalovirus were measured in 120 students of normalschool and 107 "gymnasiasts". The proportion between negative and positive was 1.1 for students in normalschool and 2.7 for those attending a higher education.