Influenza (Flu) Immunization: Myths and Facts

HealthLink BC File #12c, November 2009

Influenza (Flu) Immunization: Myths and Facts

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Getting immunized against influenza or the ‘flu’ is a safe, effective and healthy choice to make. The influenza virus can cause serious illness and even death for people with certain chronic health concerns. The influenza vaccine, or flu shot, is the best protection against illness and complications. During the 2009-10 influenza season two vaccines are available: one for seasonal influenza and one for pandemic H1N1. For more information on the seasonal influenza vaccine, see HealthLink BC file# 12d: Seasonal Influenza (Flu) Vaccine. To learn more about the pandemic H1N1 vaccine, see HealthLink BC file# 108b: Pandemic H1N1 (pH1N1) Influenza Vaccine.

Many people use the term the ‘flu’ to refer to any illness caused by a virus, such as ‘stomach flu’ or the common cold. However, the influenza virus causes illness that tends to be more severe than other viruses.

This HealthLink BC file provides information on the myths and facts of influenza immunization.

Myth: Influenza is not a serious illness.

Fact: Each year in BC, hundreds of people die from influenza or complications, such as pneumonia. Seasonal influenza in people 65 years of age and older, and in other high risk groups, can lead to more serious health concerns. Pandemic H1N1 (pH1N1) influenza is more serious in younger people.

Myth: You have never had influenza so you do not need to get the vaccine.

Fact: No one is immune from new influenza viruses as these mutate often. Most people can get sick with influenza several times over the course of their life. An influenza vaccine, or flu shot, is the best protection against the influenza virus.

Myth: The influenza vaccine can give you influenza.

Fact: The influenza vaccine cannot give you influenza. The influenza vaccine contains dead influenza viruses that cannot cause infection

Myth: The influenza vaccine causes severe reactions or side effects.

Fact: The influenza vaccine is very safe. Most people have no symptoms after getting the influenza vaccine other than redness or soreness where the needle was given. Some people, especially those getting the shot for the first time, may have muscle aches or tiredness which they think is the flu. These are much less severe than influenza infection, and last for a much shorter time.

Guillain-Barré Syndrome (GBS), a form of paralysis which is usually temporary and can occur after some common infections, may be associated with influenza vaccine in about 1 per million recipients.

Myth: Getting an influenza vaccine every year weakens your immune system

Fact: The influenza vaccine prepares and boosts your immune system against the virus. People who get the influenza vaccine each year are better protected against influenza than those who do not get it.

Myth: You should not get the influenza vaccine because you have allergies.

Fact: Most allergies are not a reason for not getting an influenza shot. People who have had a severe allergic reaction to a previous dose of the influenza vaccine or to eggs should talk to their doctor as the vaccine may not be recommended for them before further testing.

Myth: The influenza vaccine protects against the viruses or bacteria that cause colds or stomach illnesses.

Fact: The vaccine does not protect against the viruses or bacteria that cause colds or stomach illnesses, often called ‘stomach flu’. The influenza virus is very different and more severe than the common cold or the ‘stomach flu’. Influenza vaccine only helps to protect against the viruses that cause influenza.

Myth: The vaccine does not work because you still get influenza.

Fact: At any time, there are many different types of viruses around that can cause symptoms like influenza, but these are not actually the influenza virus.

The seasonal influenza vaccine protects against the three types of influenza viruses that health experts think are likely to cause influenza during the winter. The vaccine protects against only those viruses. Because these strains may change each year, a person needs to get the influenza vaccine each year to be protected against new strains.

When the strains in the vaccine are well-matched to the strains of influenza virus in the community, the vaccine prevents influenza in more than 7 of 10 vaccinated persons. In elderly people and people who have certain chronic health conditions, the vaccine may not work as well to prevent infection, but it still decreases symptoms and the risk of serious health concerns or complications.

Myth: You are pregnant and should not get the influenza vaccine.

Fact: Women in the second half of pregnancy are at high risk of complications from influenza. As well, pregnant women who have certain chronic medical conditions such as diabetes or asthma or who are health care workers should be immunized at any stage of pregnancy. Seasonal influenza vaccines have been shown to be safe at any stage of pregnancy. Pandemic H1N1 vaccine is strongly recommended for pregnant women in the fall of 2009.

Two Pandemic H1N1 vaccines will be available. Depending on the stage of pregnancy and other risk factors, a pregnant woman should receive one of these vaccines. It can be given at the same time as seasonal influenza vaccine. If you are pregnant, a discussion with your health care provider will help determine which vaccine is best for you.

Mothers with babies and toddlers younger than 2 years should get the seasonal influenza vaccine if not immunized during pregnancy. Mothers with babies under 6 months of age should also get the pandemic H1N1 influenza vaccine if not immunized during pregnancy. Children under 2 years old are at higher risk of hospitalization from complications of influenza, and those under 6 months old cannot be vaccinated because their immune response to the vaccine is not as strong.

Vaccination for mothers and other household contacts including staff of child care centers can help protect young children and reduce their risk of infection. It is safe for babies to breastfeed after mothers receive the influenza vaccine.