Annual Flu Vaccine Basics

September 26, 2013

GETTING A FLU vaccination each year is one of the best ways to protect yourself and your family against serious illness caused by influenza infection. Although the flu shot is important for everyone, it is especially important for the following at-risk individuals:

  • Infants over 6 months old and seniors ages 50 years and up.
  • Patients with chronic conditions such as lung or heart disease, diabetes or anemia.
  • Healthy pregnant women, health-care workers and other caregivers who can pass on the virus to the above at-risk groups.

These persons can contract influenza more easily than other population groups.

What is a flu shot and what is it made of?

A vaccine is made up of "germs" (viruses or bacteria) that have been weakened or killed. In some cases, a vaccine is just parts of a germ's outer shell. When injected into the body, the vaccine forces the immune system to recognize the germs and create antibodies to attack them. Therefore, when the real germs try to invade they are immediately recognized and killed. Therefore, the flu (influenza) shot each year protects the recipient from getting sick with the flu. With the flu shot, the body immediately recognizes the virus and know how to react.

The flu vaccine contains:

  • Parts of the outer shell. There are two types of influenza viruses to primarily worry about: A and B. The outer shell of the influenza virus contains two proteins: hemagglutinin (H) and neuraminidase (N). Each year, these proteins change slightly, making a new strain of the virus that causes the flu. This is why flu virus names often have an H and an N, followed by a number (for example, H1N1), indicating what influenza strain is causing the flu. The vaccine contains only parts of the outer shell of the three strains that the World Health Organization predicts will most likely be circulating and infecting people in the upcoming flu season.
  • Adjuvant. This substance helps increase your immune response to a vaccine, making it work better and longer. Not all flu vaccines contain an adjuvant.
  • Preservative. This helps keep the vaccine vials sterile and germ free. Preservatives are usually used only in flu vaccine vials designed for multiple doses.
  • Stabilizer. This helps keep the important vaccine ingredients from breaking down, so they can continue to work properly. It's important to discuss your allergies with your doctor or pharmacist before requesting the flu shot. Health Canada approves each season's vaccine after it has reviewed the clinical trials in humans to make sure that it's safe and effective.

The fact that the flu shot is made of only parts of the outer shell explains why you can't get the flu from a flu shot.

For more information on the flu vaccine, call or visit your MEDOCare Pharmacist at 204-942-7200 or 1-877-635-5931. You can also visit the Public Health Agency of Canada website,

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