Rubella and Congenital Rubella Syndrome in Japan: Epidemiological Problems

Rubella virus infection can lead to problems with congenital rubella syndrome (CRS) in the next generation due to fetal infection, but these problems are preventable with vaccination. In other words, rubella epidemics and the occurrence of CRS can be eliminated by vaccination. In Japan, until recently, rubella epidemics occurred every 5 years, and there were at least 1,600 CRS cases between 1965 and 1985. Following the 1994 revision of the Preventive Vaccination Law, national surveillance from approximately 3,000 clinics has shown that the number of rubella cases has dramatically decreased to a few thousand and the occurrence of CRS has decreased to only a few cases. However, the vaccination rate during a transitional period from 1995 to 2003 has been unsatisfactory. This has been especially true for junior high school students, because individual vaccination has replaced mass immunization in urban areas. As a result, the negative antibody rate in females below 18 years of age has increased to approximately 27%. If this trend continues, there is likely to be an increase in rubella epidemics and occurrence of CRS in the near future. Vaccination is not compulsory under Japanese law, and vaccination campaigns alone have proved unsuccessful in promoting vaccination. Another system of motivating individuals to seek vaccination will be needed in order to maintain a high vaccination rate without such campaigns.