Flu Vaccine Myths

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Flu Vaccine Myths

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Many people choose not to have the influenza vaccine because of myths they believe about the disease or the vaccine.

Myth: Influenza is a minor illness.

Truth: Influenza and its complications cause from 4,000 to 8,000 deaths in Canada each year.1

Myth: The vaccine causes the flu.

Truth: You cannot get the flu by having a flu shot. Influenza vaccine is made of killed virus and therefore cannot cause the flu. And the weakened viruses in the flu nasal spray vaccine can cause symptoms similar to a cold, but they can't cause the flu

Myth: The vaccine causes unpleasant side effects.

Truth: The vaccine causes no side effects in most people. Earlier vaccines (1940s to 1960s) did, in fact, have more, unpleasant side effects.

Myth: The vaccine is ineffective because some people had a flu-like illness after having the shot.

Truth: Although getting the vaccine prevents most people from becoming ill with the flu, some people still become infected. This may occur because a person is exposed to the virus before getting a vaccination or before it has taken effect, or because the vaccine does not match the circulating virus closely enough. A mild illness similar to a cold also can be caused by the live, weakened viruses in the influenza nasal spray vaccine. But any illness is usually milder than it would be without having had the vaccine.



  1. Stevenson CG, et al. (2001). Prevention of influenza and pneumococcal in Canadian long-term care facilities: How are we doing? Canadian Medical Association Journal, 164(10): 1413–1419.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Christine Hahn, MD - Epidemiology
Last Revised September 17, 2010

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