In terms of disease prevention, reduction of adverse reactions, and cost benefit studies, a strong case can be made for a policy that focuses on assuring high levels of primary immunization with tetanus and diphtheria (Td) toxoids and abandons the decennial Td booster in favor of a single midlife booster at age 50-65 years. The addition of acellular pertussis antigens to Td for routine use in adults has potential problems in terms of schedule, cost, and possible adverse reactions. Careful risk/benefit studies are necessary to evaluate its effectiveness and priority.