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It takes about two weeks for the flu vaccine to become effective.JEFF MCINTOSH/The Canadian Press

The question: My doctor recommended that I get the flu shot again this year. I've heard people say they get the flu when they get the vaccine and given that I'm 34 and healthy I'm not sure it's really necessary. Do you recommend it to patients like me?

The answer: With flu season upon us, your question is a common one. Despite what many think, influenza is serious and for some it's a potentially deadly infection. The flu shot is one of the best defences for protection.

Like any medical intervention, vaccinations can carry some risk so it's important to know what's true and what's not to make an informed decision. Let's dispel some of the myths to understand why the flu shot can help, even when you're healthy.

Myth 1: The flu shot gave me the flu

The flu vaccine contains inactivated viral proteins so it is impossible for these parts to cause the flu. If you had the vaccine and got sick within the first couple of weeks, it is probably because the vaccine had not yet triggered an immune response. It takes about two weeks for the vaccine to become effective.

Myth 2: I had the flu shot but I still got the flu

The effectiveness of the flu shot depends upon how well the vaccine is matched to the circulating strain of the season. In general, the flu shot is considered 70 to 90 per cent effective against the most common strains. There are also other viruses that can cause colds and flu-like illnesses, which may not be prevented by the flu shot.

Myth 3: I'm pregnant and it's not safe to be vaccinated

While pregnant women are not more likely to get the flu, they have a lower immune response and as such are at a higher risk of developing complications such as pneumonia, bronchitis and the need for hospitalization. This is especially relevant for pregnant women in their second and third trimesters and up to six weeks post-delivery. It has also been found that infants whose mothers had been immunized in pregnancy also had reduced rates of influenza in comparison to those born to moms who were not vaccinated. So you're not only protecting yourself by getting vaccinated when you're pregnant but also potentially protecting your child as well.

Myth 4: I'm healthy, I don't need the flu shot

Even if you're healthy, you can still get the flu and feel pretty miserable. Also, you can pass it on to others around you who may be more prone to the severe effects of the flu. If you have contact with anyone in one of the high risk groups (those over 65, pregnant women, children between six months to two years old, people with chronic medical illnesses or who are immunocompromised), consider getting the shot to not only protect yourself but more so to protect your loved ones and others at risk.

Myth 5: I had the flu shot last year so I'm going to skip out this year as I'm probably still protected

There are different circulating strains of the virus every year. So your previous vaccination may not fully protect you against this year's particular strain.

Ultimately, the decision to get the flu shot will depend upon your personal wishes, your level of health and the health of those around you. For most, the benefit will greatly outweigh the risk of the vaccine so discuss with your family doctor and make an informed choice that is right for you.

Dr. Sheila Wijayasinghe is the medical director at the Immigrant Womens' Health Centre, works as a staff physician at St. Michael's Hospital in their Family Practice Unit and at Hassle Free Clinic, and established and runs an on-site clinic at Women's Habitat Shelter in Etobicoke.

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