Frequently asked questions about influenza vaccines

Why should I get vaccinated against influenza?

Getting vaccinated is the best way to protect against influenza, a serious and sometimes fatal infection. In years when influenza is widespread in B.C., hundreds of people may die from influenza or its complications, such as pneumonia. Influenza can lead to serious illness in seniors over 65 years and in other high-risk groups. Even healthy people can get very sick from influenza. When you get vaccinated, you help protect others as well by reducing the spread of the influenza virus.

How do influenza vaccines work?

Influenza vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection with the viruses that are in the vaccine. Learn more about how vaccines work here.

Influenza vaccines are designed to protect against the influenza viruses that research indicates will be most common during the upcoming influenza season. "Trivalent" influenza vaccines are made to protect against three different influenza viruses and "quadrivalent" vaccines are made to protect against four different influenza viruses. 

Why do I need an influenza vaccine every year?

An influenza vaccine is needed every year for two reasons:

1. Influenza viruses are constantly changing so each year the viruses used to make the vaccine change to protect you against the viruses circulating that year.

2. Protection from the influenza vaccine declines over time. 

What viruses do the 2017/18 influenza vaccines protect against? 

The 2017/18 influenza vaccines protect against the following viruses: 

  • A/Michigan/45/2015 (H1N1)pdm09-like virus
  • A/Hong Kong/4801/2014 (H3N2)-like virus
  • B/Brisbane/60/2008-like virus
  • B/Phuket/3073/2013-like virus (in quadrivalent vaccines only)

Who should get vaccinated against influenza?

Canada's National Advisory Committee on Immunization recommends that everyone 6 months of age and older gets an influenza vaccine, with rare exception. Some people are at high risk of serious illness from influenza, such as children 6 months to less than 5 years of age, pregnant women, seniors 65 years and older and people with certain medical conditions. Vaccination is especially important for these people.

Who is eligible for a free influenza vaccine?

In B.C., the influenza vaccine is provided free to people who are at high risk of serious illness from influenza (such as young children, pregnant women, the elderly and people with certain medical conditions), those able to transmit or spread influenza to those at high risk and people who provide essential community services.

For a list of people eligible for the free inactivated influenza vaccine, see the HealthLinkBC File: Inactivated Influenza (Flu) Vaccine.

For a list of people eligible for the free live attenuated influenza vaccine, see the HealthLinkBC File: Live Attenuated Influenza (Flu) Vaccine.

Anyone not eligible for a free influenza vaccine can purchase it at most pharmacies and travel clinics. Some employers also provide free vaccines to employees.

Are influenza vaccines safe for pregnant women?

The inactivated influenza vaccine (flu shot) is considered safe at any stage of pregnancy. Women in the second half of pregnancy are at higher risk of influenza-related complications and at higher risk of hospitalization from these complications, especially those in the third trimester. As well, women at any stage of pregnancy who have chronic medical conditions are also at higher risk of serious influenza complications and should be immunized.

It is not known if the live attenuated influenza vaccine is safe during pregnancy. Pregnant women, or those intending to become pregnant, should receive the inactivated influenza vaccine (flu shot), which contains killed influenza viruses that cannot cause infection.

When should I get vaccinated?

Influenza season in Canada generally runs from November through April. In B.C., influenza vaccines are usually available starting in October. Though you can receive this vaccine at any time during the influenza season, for best protection, you should get immunized as early as possible.

Where can I get an influenza vaccine?

Influenza vaccines are provided at a wide variety of locations across the province including:

  • Public health clinics
  • Pharmacies 
  • Doctors’ offices
  • Travel clinics  

You can use our Influenza (Flu) Clinic Locator to find an influenza vaccine clinic near you.

How well do influenza vaccines work?

The influenza vaccine is the best way to protect against influenza. How well the vaccine works varies from season to season. It depends on how well matched the influenza vaccine is with the viruses circulating during the season and on the health and age status of the person being vaccinated. When the influenza vaccine is well matched with the circulating viruses, it prevents influenza in about 60% to 80% of adults and children receiving the vaccine. Effectiveness is less in elderly adults, but studies have demonstrated that the influenza vaccine decreases the incidence of pneumonia, hospital admissions and death in the elderly population.

Can influenza vaccines give me influenza?

The inactivated influenza vaccine (flu shot) cannot give you influenza. This vaccine contains killed influenza viruses that cannot cause infection.

The live attenuated influenza vaccine given as a nasal spray contains weakened influenza viruses. Common reactions to the live vaccine include mild symptoms, such as runny nose, nasal congestion, cough, sore throat and fever. These symptoms are less severe than those from influenza infection and last a shorter time. As a precaution, people with weakened immune systems should not get the live vaccine.