There are good data to recommend routine use of vaccines against measles, rubella, tetanus, influenza, and pneumococcal infections in adults. An adolescent or an adult born after 1956 is considered to be susceptible to measles unless he or she has received two doses of live measles vaccine or has suffered a physician-diagnosed case of measles. Tetanus is largely a disease of the elderly, and there is a universal need for immunizations with tetanus toxoid. Influenza continues to be a major public health problem, and influenza vaccine should be given annually to the elderly and to those at high risk. The efficacy of pneumococcal vaccine in American adults is still being debated. Results from case-control studies show that the vaccine is about 60% effective in reducing the incidence of disease due to vaccine-related strains. Its use in the elderly and in those at higher risk for pneumococcal infection is recommended.