Measles vaccines used in Japan.

The history of the research and development of measles vaccines is described and the efficacy of and adverse reactions to the Japanese licensed vaccines are discussed. The 10-year follow-up studies revealed that the incidence of clinical measles was 11.5% among those inoculated with live vaccines in combination with killed vaccines, whereas it was only 1.9% among those given live vaccines attenuated to the level of the Schwarz vaccine. Use of the Schwarz and Biken-CAM vaccines resulted in satisfactory antibody responses in greater than or equal to 97% of vaccinees. However, these vaccines caused a febrile reaction of greater than or equal to 37.5 C in 50% of vaccinees and one of greater than or equal to 39 C in 15% of vaccinees. On the other hand, a febrile reaction was observed in 20% and 5%, respectively, of children immunized with the AIK-C vaccine or the further-attenuated Schwarz vaccine, both of which were developed in Japan. The worldwide use of further-attenuated vaccines is strongly recommended. The system of fixed surveillance stations, which was started in 1981 by the Japanese government with the voluntary cooperation of pediatricians and ophthalmologists, is described. This system proved effective in obtaining information about the prevalence of communicable diseases, including measles, in childhood and about the efficacy of vaccines.