Experience with diphtheria toxoid-tetanus toxoid-acellular pertussis vaccine in Japan.

In Japan, the morbidity rate for pertussis per 100,000 population was 147.6 in 1950 when whole cell pertussis vaccine was introduced but dropped to 0.2 in 1972 when routine immunization with a combined vaccine consisting of diphtheria toxoid, tetanus toxoid, and whole cell pertussis had been widely accepted. Thereafter, adverse reactions to the whole cell pertussis vaccine became a social problem and lowered the acceptance of the vaccine. As a result, the morbidity rate increased to 11.3 in 1979. Introduction of the safer yet efficacious acellular pertussis vaccine, consisting of mainly pertussis toxoid and filamentous hemagglutinin, into the routine childhood vaccination in combination with diphtheria and tetanus toxoids in 1981 increased the acceptance rate. The lowest morbidity rate, 0.1, was achieved in 1993. During the next 16 years, almost all cases were in unvaccinated or incompletely vaccinated persons. Regardless of whether whole cell or acellular pertussis vaccine was used, > 90% of the reported pertussis cases were in children < 10 years of age until 1990. However, since 1991, the rate of pertussis in young adults 20-44 years of age has been clearly increasing. To control pertussis, booster vaccination with diphtheria toxoid-tetanus toxoid-acellular pertussis vaccine in adults should be considered.