Prevention of influenza by expanded ages for routine vaccination.

Influenza viruses are highly contagious and are transmitted from person to person, usually by the airborne route. Persons in semiclosed or crowded environments, such as students and residents of nursing homes, are at high risk for exposure. Fatality rates are highest in persons who have chronic medical conditions such as chronic obstructive lung disease and diabetes mellitus, particularly if they are elderly. When there is a good match between the vaccine and the circulating viruses, influenza vaccine has been shown to prevent illness in approximately 70% to 90% of healthy persons younger than 65 years. Despite the availability of an effective vaccine, it is underused. The Advisory Committee on Immunization Practices (ACIP) and the American Academy of Family Physicians (AAFP) now recommend that all persons aged 50 years and older receive annual influenza vaccination because of the suffering from influenza and the cost-effectiveness of vaccination. Reasons for lowering the recommended age for routine vaccination from 65 years to 50 years include reductions in office visits, hospitalizations, time taken off work, and costs. Persons younger than 50 years who have medical conditions that place them at risk for complications should also be vaccinated. If a vaccine shortage occurs, which may happen in the Fall 2000, then priority would be given to the elderly and those with high-risk conditions.