Surveillance of congenital rubella syndrome in Japan, 1978-2002: effect of revision of the immunization law

Infection of rubella virus at the early stages of pregnancy in women who are not immune to rubella often induces congenital anomalies in infants, namely congenital rubella syndrome (CRS). This paper is the first comprehensive report of CRS cases in Japan, compiled from a questionnaire to major hospitals, reports to journals and academic meetings, and cases for virus/virus genome verification submitted to the National Institute of Infectious Diseases. CRS incidence in Japan was determined to be 0.2-8.1 cases/100,000 live births per year in epidemic years and 0.1-0.7 in non-epidemic years, respectively. In the last 4 years, the number of CRS cases remarkably decreased to one-three cases per year. This decrease is thought to be because the immunization law was revised in 1994 for changing the focus of rubella immunization from junior high school girls to infants of both sexes.