Flu Vaccine Protects Millions Annually: CDC

Flu shots likely prevented 13 million illnesses and more than 110,000 hospitalizations in the United States between 2005 and 2011, according to a new study.

The impact of flu vaccination was greatest during 2010-2011, when 5 million flu cases, 2.1 million medical visits and 40,400 hospitalizations were avoided, according to researchers from the U.S. Centers for Disease Control and Prevention. The findings, published June 19 in the journal PLoS One, are based on a calculation of the health-care burden of flu cases that would have occurred in the absence of vaccination. Factors such as illness and hospitalization rates during the flu season, vaccination coverage and vaccine effectiveness were considered in the calculation.

"These results confirm the value of influenza vaccination, but highlight the need for more people to get vaccinated and the imperative for vaccines with greater efficacy, especially in the elderly," study senior author Joseph Bresee, chief of epidemiology and prevention in the CDC's influenza division, said in a journal news release. The United States is the only country with universal influenza vaccine recommendations that suggest everyone aged 6 months and older should receive an annual flu vaccination, the researchers said. They added that previous studies have not provided ways to reliably assess the number of flu cases or hospitalizations prevented by vaccination each year.