Long-term epidemiologic longitudinal study on the effect of vaccines on public inoculation.

Public vaccination policies in Japan for several viruses have achieved favorable results. To accurately evaluate their overall effectiveness, we conducted a 45- year epidemiological survey of measles, varicella and mumps cases at our clinic. The number of patients with measles was found to be significantly decreased with the single-dose vaccination provided at public expense. However, we also witnessed an increasing trend of infection at a later age. The vaccination rates for varicella and mumps were relatively low because of their optional availability in Japan, and thus they cannot be considered to confer public protection. Although localized to a particular region, our results show that it is important to increase the immunization rate of vaccines for large-scale protection against viral infections through public programs.