Which immunization is recommended annually for adults?

The influenza vaccine is recommended annually for adults due to the virus's ability to mutate and create new strains each year. This annual vaccination helps ensure that individuals have the most current protection against the prevalent strains of influenza, thereby reducing the risk of severe illness, hospitalization, and complications that can arise from influenza infection.

In contrast, the pneumonia vaccine provides protection for several years and generally is not required annually. The shingles vaccine is typically given once or as a booster after a set period, not annually. The tetanus booster is recommended every ten years, although more frequent doses may be indicated following certain injuries, but it does not require annual administration. Thus, the influenza vaccine stands out as the immunization that adults should receive every year.