Flu Information

Last Updated: 2021-11-05

Influenza (Flu) is a respiratory virus that has similar symptoms to COVID-19. It can have a big impact on the health care system as it can cause severe illness, especially in children under five, people who are pregnant, older adults and people who have chronic health conditions.

Getting the flu shot protects you and also helps protect others; the more people get the flu shot, the less opportunity for influenza to spread in our communities.

Below you will find information on the influenza virus and what you can do to protect yourself and those closest to you from the flu.

General Information about influenza

What is influenza?

  • Influenza is a disease caused by an influenza virus infection.
  • Symptoms may include fever, headache, runny nose, cough and muscle aches.
  • People who are infected usually start to feel sick between one to four days after exposure to the virus.
  • Influenza is often called “the flu,” but people use the term “flu” to refer to many other infections as well.
  • Influenza can be mistaken for the “common cold,” however, flu symptoms are usually more severe.
  • In Canada, almost all influenza occurs between November and April. Most influenza occurs in a 10-to-16-week period that usually starts in December, but can start at any time from late October to mid-February.
  • Influenza can cause serious complications such as pneumonia.

Who is at risk of becoming seriously ill from influenza?

Young children, older adults, people who are pregnant and people with chronic illnesses are at the greatest risk of experiencing serious complications from influenza.

How easily is influenza spread?

Influenza is very easily spread by touch (e.g. kissing, shaking hands and then touching the face), as well as by droplets expelled during breathing, talking, sneezing or coughing. When one person in a household has influenza, there is a 15 per cent chance that someone else will get it.

Information on the influenza vaccine

What is the influenza vaccine?

  • Flu vaccines are a safe and effective means of preventing both mild and severe cases of influenza.
  • The flu vaccine is made up of proteins from killed influenza viruses.
  • Because there are different influenza strains every year, the vaccine is updated annually. You should get an influenza vaccination every year, preferably in October or November.
  • The flu vaccine starts working a few days after you get it and is fully effective after 14 days. It will continue to protect you for at least nine months.
  • Current influenza vaccines are very effective in preventing illness in healthy adults under 65 years of age. In older adults and those with medical illnesses, flu vaccination effectively prevents serious illness, hospitalization and death. In other words, it reduces illness but does not eliminate it.

Can the influenza vaccine give me the flu?

As the vaccine is made up of killed virus, it will not cause influenza. It will only cause your body to create antibodies to protect against the virus.

We give the influenza vaccine in October, when many viruses that cause fevers and “colds” are circulating, therefore, since the vaccine doesn’t protect you against these other respiratory viruses, people can get sick after getting their influenza vaccine. In studies in which people are given either the influenza vaccine or placebo injection, there is no difference in symptoms such as fever and tiredness between the two groups.

Does getting the influenza vaccine reduce the risk of getting COVID-19?

The influenza vaccine does not protect against COVID-19. Now more than ever it’s important that people also get the flu shot. This year experts anticipate greater flu activity compared to last year. As the COVID-19 pandemic continues to improve in Canada, public gatherings have been increased which may create more potential for influenza to spread.

Getting the flu shot protects you and also helps protect others; the more people get the flu shot, the less opportunity for influenza to spread in our communities. This conserves health care resources for patients who have COVID-19 or any other conditions that require hospital care. It’s important that everyone get the flu shot to help stop the spread of influenza.

Can I have my flu shot at the same time as my COVID-19 vaccine?

The seasonal flu shot may be given at the same time or at any time before or after administration of other vaccines, including COVID-19 vaccines.

What are the side effects of the influenza vaccine?

  • The most common side effect is a sore arm (at the site of injection) following vaccination. This usually lasts for a few hours but in some instances may last a few days.
  • About one in 10,000 people experience red, itchy eyes, dry cough and sore throat. These symptoms are usually mild and last only a few hours.
  • Studies have found no adverse long-term effects.
  • The new purified influenza vaccines we use do not cause fever, tiredness or muscle aches.

Should my children be vaccinated?

The Canadian National Advisory Committee on Immunization (NACI) recommends that all children over six months of age be vaccinated against influenza. Children who are sick with influenza can develop ear infections, pneumonia, dehydration and febrile seizures. Influenza is the sixth leading cause of death in children less than five years of age.

Children under six months of age are too young to respond well to the vaccine, but can get seriously ill from influenza. Vaccinating their household and close family members (parents, siblings, caregivers etc.) will help to protect them from influenza. Infants with siblings are three times more likely to get influenza than infants without siblings.

If I have an egg allergy, I can still get the influenza vaccine?

  • The National Advisory Committee on Immunization (NACI) has concluded that egg allergic individuals may be vaccinated against influenza with the full dose of any injectable influenza vaccine in any setting where vaccines are routinely administered.
  • This change is as a result of new data demonstrating that vaccine is safe for individuals with egg allergies; serious allergic reactions have not been reported.
  • As always, immunizers administering vaccine should be prepared for and have the necessary equipment to respond to a vaccine emergency at all times.

Is there anyone who should not get vaccinated?

People who have had allergic reactions to other vaccines or who have been diagnosed with Guillain Barré Syndrome after an influenza vaccination should consult with a physician before being vaccinated.

How can family and visitors help prevent the spread of influenza?

The most effective way to prevent the spread of influenza is by getting a flu shot and cleaning your hands regularly. If your family or visitors have not received their flu shot, please encourage them to get their flu shot and to not visit if they are unwell with fever, cough, sore throat, runny nose or diarrhea.

When I get the influenza vaccine, how does that help protect other people from getting influenza?

While getting your vaccine protects you directly, you are also protecting the others around you because you are less likely to get the flu and spread it to others. This could be family, friends or people you work with, including those at risk of serious complications from influenza.

Influenza and Pregnancy

I am pregnant. How can I protect myself from getting the flu?

  • The influenza vaccine is recommended as a priority for anyone who is pregnant or breastfeeding by (among others) the Canadian National Advisory Committee on Immunization (NASCI), The Canadian Society for Obstetrics and Gynecology and the US Centers for Disease Control.
  • Healthy women who are pregnant and in their second and third trimester of pregnancy are two to four times more likely to be hospitalized due to influenza than those who are not pregnant. Of 1,000 pregnant people in their third trimester, three to five otherwise healthy individuals will be hospitalized for influenza related complications.
  • Studies have shown that pregnant women who get vaccinated are less likely to have babies who are premature or small for their gestational age.
  • The protective effect from the flu shot is passed through the placenta, providing protection for the first six months of life.

Is it safe to get the influenza vaccine while pregnant?

It is safe to receive the flu shot during any trimester of pregnancy and while breastfeeding. The flu shot will not cause any harm to your baby. More than two million pregnant people in the US and Canada get vaccinated every year. No serious side effects associated with pregnancy have been found.

What should I do if I still have questions or concerns?

If you have questions or concerns about influenza, or the influenza vaccine and pregnancy, ask your doctor. You can also check out the phone numbers or web sites listed below: