How effective is the seasonal flu shot and H1N1 vaccine?

Dr. David L. Katz, MD, MPH
Preventive Medicine
There is some legitimate doubt about the effectiveness of the flu vaccine. It is certainly far from perfect, and the elderly, who most need protection, may need two inoculations to get it. Leaving aside some of the subtleties that complicate measuring vaccine effectiveness in real-world settings, and applying even a low-level estimate of overall vaccine effectiveness, routine flu vaccination produces a decisive overall benefit compared to just taking our chances with the flu.
The seasonal flu vaccine protects against three flu influenza viruses, including H1N1. There is not a separate vaccine for H1N1. The effectiveness of flu vaccine varies from season to season. How well the vaccine works depends on the age and health of the person who receives it and how closely it matches the virus the person is exposed to. Some seasons the vaccine is very effective, and some years it does not protect well against the flu. The best way to lower the risk of getting and spreading H1N1 or any strain of flu is getting a seasonal flu shot.
Dr. Michael Roizen, MD
Internal Medicine
Flu shots are about 70 percent effective at preventing the flu in populations under sixty-five years of age, and somewhat less effective in people over sixty-five. The shots also reduce the severity of the symptoms in people who actually do get the flu. One study found that taking vitamin E and exercising, which boost the immune system, also seemed to improve the overall effectiveness of the vaccine.

Continue Learning about H1N1 (Swine Flu)

H1N1 (Swine Flu)

H1N1 (Swine Flu)

H1N1, or swine flu, is a strain of the influenza virus that was originally limited to pigs, and first detected in people in 2009. It is not considered particularly harmful in people with healthy immune systems; in people with comp...

romised immune systems, H1N1 can cause bacterial pneumonia, ear infections, bronchitis or sinus infections.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.