Flu Shots May Have Prevented Millions From Illness in the US

(July 10, 2013)

Influenza vaccine reduced disease outcomes by up to 18.5 percent, study estimates

Fighting influenza, funding flu research and supporting annual campaigns to promote flu vaccination are all important aspects of the American Lung Association’s mission, and a recent study finds that flu shots may have prevented millions from illness in the US.

Approximately 13 million illnesses and over 110,00 hospitalizations may have been averted by the flu vaccine over the last 6 years in the U.S, according to calculations published June 19 in the open access journal PLOS ONE by Deliana Kostova and colleagues from the U.S Centers for Disease Control and Prevention.

The researchers calculated the healthcare burden of flu cases that would have occurred in the absence of vaccination based on factors such as illness and hospitalization rates during the flu season, vaccination coverage and vaccine effectiveness. Based on these data, Kostova and colleagues estimate that flu vaccines averted several million instances of illness and over 110,000 flu-related hospitalizations in the flu seasons of 2006 to 2011. The largest number of averted cases occurred during the most recent period studied, 2010-2011, when 5 million flu cases, 2.1 million medical visits and 40,400 hospitalizations were prevented by vaccination.

The U.S is the only country with universal influenza vaccine recommendations that suggest everyone aged 6 months and older should receive an annual dose of the vaccine. However, previous studies have not provided ways to reliably assess the number of flu cases or hospitalizations that are prevented by vaccination each year. Senior author on the study Joseph Bresee adds, "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".

Read the full open access PLOS ONE article: Kostova D, Reed C, Finelli L, Cheng P-Y, Gargiullo PM, et al. (2013) Influenza Illness and Hospitalizations Averted by Influenza Vaccination in the United States, 2005. PLoS ONE 8(6): e66312. doi:10.1371/journal.pone.0066312