Safety concerns regarding combination vaccines: the experience in Japan.

This study explored the safety concerns associated with combination vaccines in Japan. The impact of Japan's decision in 1975 to withdraw the combined diptheria, tetanus, and pertussis (DTP) vaccine, and then in 1993, the combined measles, mumps, and rubella (MMR) vaccine and provide only the single antigen vaccines was analyzed. Interviews with both governmental and non-governmental agency officials in Japan demonstrated that withdrawal of the DTP and MMR vaccines had significant impact on the rates of immunization and disease despite the availability of monovalent vaccines.