Adult Immunizations give the longest-lasting, most efficient protection against disease at any age. Some infections, such as tetanus (lockjaw) and diphtheria, do not respond to childhood immunization.

Adults require booster immunizations in order to maintain immunity. Adults who were not adequately immunized as children may be susceptible to infection from other vaccine-preventable diseases. They may also infect people who are not infected. Adults who get measles, mumps, or rubella (German measles) can give it to infants who have not been fully immunized. Only adults can benefit from most new vaccines, such as herpes zoster (shingles).