Is the influenza vaccine effective in decreasing infection, hospitalization, pneumonia, and mortality in healthy adults?

The annual influenza vaccine is universally recommended by the CDC for individuals greater than six months of age. However, unlike the other 16 routinely recommended vaccines, influenza vaccination is annual and developed based on circulating strains that are constantly modifying the primary immune targets, the hemagglutinin and neuraminidase receptors. Given the variation in these critical receptors, the need to predict changes in the protein structure, and the necessity of such frequent immunizations it is reasonable to question the annual vaccinations efficacy, especially in otherwise healthy adults. This article will review literature on inactivated influenza vaccine efficacy on preventing infection, decreasing hospitalizations and pneumonia, and mortality.