A flu shot can decrease your risk of catching influenza, but it’s no guarantee. In the 2010-11 flu season, for example, the flu vaccine was only about 60% effective overall. Fortunately, you may be able to optimize the effectiveness of a flu shot by stressing less, socializing more, and being physically active.
Shooting Down the Flu Shot
Scientists who study the link between psychology and immunology can’t go around exposing hapless volunteers to active viruses to see what happens. So they often do the next best thing: studying how people’s immune systems respond to inactivated viruses in vaccines. In the process, they’ve learned some fascinating things about how stress influences the effectiveness of flu shots.
There’s now ample evidence that chronic, severe stress—such as the stress of caring for an aging spouse with dementia—can hamper the immune system’s ability to make protective antibodies. A meta-analysis of 13 studies showed that people with stress-filled lives had a decreased antibody response to flu vaccine.
Even under the best circumstances, flu vaccine is much better at preventing illness in the young than in the old, whose aging immune systems may not function as efficiently as they once did. Yet stress still seems to blunt the antibody response to flu vaccine in young, healthy adults, who presumably have robust immune systems.
In a study of college freshmen, for example, those who said they felt moderately stressed made fewer antibodies in response to flu vaccine than those who felt less stressed. Antibody production was down both one month after getting a flu shot, when vaccine response peaks, and four months afterward, as the response weakens.
A Shot in the Arm for Vaccine
What can you do to help your flu shot work as well as possible? Scientists don’t have definitive answers yet, but research suggests that these steps might be helpful: