Flu shot facts versus fiction

Debunking the most common myths and misconceptions about the flu shot
Dec. 14, 2009 | By: Alison Dunn

U.S. talk show host Bill Maher stirred up controversy in October when he Tweeted that all people who get the flu shot are “idiots.” He later stated on his HBO talk show that he questioned letting someone stick “a disease in your arm,” giving voice to many people’s concerns about getting the flu shot.

The problem, however, is that Maher’s comments weren’t exactly accurate. Many people mistakenly believe the flu vaccine is a live vaccine, which, particularly in Canada, is not the case.

And while there are risks to the shot, like any medical procedure or vaccine, it is still effective at preventing some of the most prevalent forms of seasonal flu, says Dr. Joanne Langley, a Professor in the Departments of Pediatrics and Community Health and Epidemiology at Dalhousie University in Halifax.

“Like everything, there’s a weighing of the risk and the benefits,” Langley says. “Nothing is completely risk-free, but we know quite a lot about the influenza vaccines that we give each year.” Here, we take a look at some of the most common myths surrounding the flu shot.

Myth: The flu shot injects you with a live flu virus.

Fact: In Canada, the only flu shots available are inactivated, or dead, forms of the virus. Not only is it inactive, it’s also what is called a “split” virus. This means it is not the entire virus but rather parts of three different types of the influenza virus, says Dr. Monika Naus, Associate Director, Epidemiology Services and Associate Professor, School of Population and Public Health at the University of British Columbia. (There is, however, a vaccine in the United States called Flu Mist, a nasal mist that does contain a live virus. This is not available in Canada.)

Myth: You will get the flu from the flu shot.

Fact: You cannot get the flu from the flu shot, because you are not getting injected with the entire flu virus. Instead, it is simply parts of the virus put into your body in a smaller dose that allows your body to build up its own natural antibodies to fight the virus, should you encounter it later in the season.

Myth: The side effects of the shot are worse than getting the flu itself.

Fact: Most people will experience very few side effects to the shot. The most common side effect, says Langley, is pain and redness at the injection site, which occurs in approximately 30 to 40 per cent of those who get the shot.

Myth: If I get the shot, I won’t get the flu.

Fact: The flu shot cannot protect against all strains of influenza. Each spring, health authorities choose three different strains that they expect to be the most prevalent strains in the coming year, and build the vaccine based on that. For many years now, Naus says, that has been an H1N1 strain, an H3N2 strain and a B strain. “Sometimes, those predictions are bang-on, and other times, there’s a drift in the virus and we have a mismatch between the vaccine and what’s circulating,” Naus adds. So while the vaccine will protect you against the strains of the virus predicted to be the most common, there is still a slight chance you may catch another strain of the virus.

Myth: If I get the flu shot, it will protect me from the H1N1 Swine Flu.

Fact: The current seasonal flu shot will not protect against the current strain of the H1N1 virus known as the Swine Flu. You will need a separate shot to protect against this particular H1N1 strain, so speak to your health care professional about getting both vaccines this year.