On Jan. 1, 2003, the Advisory Committee on Immunization Practices (ACIP) encouraged that children 6 to 23 months of age be vaccinated annually against influenza.

Among children zero to two years of age, influenza-related hospitalization rates ranged from about 186 to 1,038 per 100,000 for healthy children to 800 to 1,900 per 100,000 for those with high-risk conditions, depending on exact age.