Getting Your Flu Shot Early Could Backfire


Trying to get ahead on your flu shots may end up creating the very thing you hoped to avoid.

Several new studies suggest that getting a flu shot in the summer months may undermine the effects of the vaccine by the time winter rolls around. Recent data released by scientists from the Centers for Disease Control and Prevention, showed that the vaccine’s effectiveness was reduced by more than 50% for two strains of the flu by five or six months after vaccination, and had diminished almost entirely for another during that same time period.

“I have been concerned for some time that we have gotten into the marketing of influenza vaccine versus the effective use of influenza vaccine. And we’ve got to reconsider that,” said Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota, to STAT. “I think the best approach is to try to make sure we get flu vaccine into people just before flu activity starts, not something convenient to when the marketers want to get people in the door of department stores and grocery stores.”

However, some medical experts said they understood the need for flu vaccines to be utilized year-round and said any potential drawbacks for getting vaccinated in the summer months are minimal.

“It is hugely disruptive to try to immunize millions of people in a six- to eight-week period beginning in October or November,” said Dr. Danuta Skowronski, a flu epidemiologist at the British Columbia Center for Disease Control. “So I understand in the context of a universal immunization program, to get the vaccine into all those arms it’s nice to be able to start earlier.”

CDC estimates indicate that the U.S. uses more than 100 million doses of flu vaccine each year and have already shipped 148 million doses each year. Once a person is vaccinated, the immune system typically generates a protective response after 14 days.

The worst of flu season is typically between December and February, although a late wave will occasionally hit in March and April. The peak month for flu shots is October, with 16-18% of those who got vaccinated receiving them in that month. Only 2.4% of those who get vaccinated do so in the summer.