1991
The diphtheria-tetanus-acellular pertussis (DTaP) vaccine is licensed. This vaccine is an acellular vaccine, which causes fewer side effects than the whole-cell DTP vaccine. The DTaP vaccine eventually replaces the DTP vaccine. In 1996, the Advisory Committee on Immunization Practices (ACIP) will recommend DTaP in infants.
About 200,000 cases of whooping cough (pertussis) occurred each year in the U.S. in the 20th century compared with about 5,000 cases in 2020. Likewise, about 21,000 annual cases of diphtheria occurred each year in the U.S. compared with none in 2020.