Flu Vaccines Offer About 6 Months of Protection, Study Finds

Early fall seems to be best time for immunization, researchers say

By Robert Preidt

Wednesday, August 26, 2015

WEDNESDAY, Aug. 26, 2015 (HealthDay News) -- Flu vaccines offer moderate protection throughout most of the flu season, a new study shows.

The research included more than 1,700 Americans of all ages. The participants all got flu shots. The researchers followed them for four flu seasons, from 2010-2011 through 2013-2014.

Annual flu shots offered up to six months of protection, the study found.

"Previous studies have found that protection from contracting influenza declines over time following influenza vaccination due to decreasing antibody levels," Dr. Jennifer Radin, of the U.S. Naval Health Research Center in San Diego, said in an American Society for Microbiology news release.

"However, we found during this study that those who received the vaccine had moderate, sustained protection up to six months post-vaccination, the duration of most influenza seasons. This means flu vaccination reduced one's risk of a doctor's visit by approximately 50 to 70 percent," she explained.

The findings suggest that giving flu shots early in the fall, before the flu season begins, may prevent the greatest number of flu cases.

Radin and her colleagues also found a sharp drop in protection after six months, which shows the value of getting yearly flu shots.

The study was presented Monday at the International Conference on Emerging Infectious Diseases in Atlanta. Findings presented at meetings are generally considered preliminary until they've been published in a peer-reviewed journal.

SOURCE: American Society of Microbiology, news release, Aug. 24, 2015

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