Influenza (Flu) Vaccine 

Learn how getting vaccinated helps protect you and your baby from serious illness caused by the flu virus.

  • Influenza (commonly known as the “flu”) is a virus that can be very dangerous for pregnant people and babies.

  • Getting the flu vaccine during pregnancy helps protect you against serious illness. It also gives your baby early protection against the flu virus.

  • Getting the flu vaccine is safe during pregnancy. It can’t give you the flu virus or cause any harm to you or your developing baby.

  • Flu vaccines are updated every year to protect against new strains of the virus. It’s important to get an updated flu vaccine every year.

About Influenza (Flu)

Influenza (‘flu’) is a viral infection. In Canada, the flu leads to approximately 12,200 hospitalizations and 3,500 deaths every year.1

The flu usually begins with symptoms like fever, chills, a headache, muscle aches, dry cough, sore throat, feelings of fatigue (feeling tired), and weakness.2 If it gets worse, the flu can also cause dehydration and lead to complications like pneumonia or bronchitis.

These problems can be dangerous for pregnant people and babies.

  • When someone with the flu coughs, sneezes, or talks, they produce tiny droplets. These droplets carry the flu virus into the air. If you breathe in those droplets, you can catch the flu, too.

  • Babies, especially those under six months, are more likely to get very sick from the flu. They are at higher risk of serious complications. They are also more likely than other children to end up in the hospital.³ Deaths from the flu are highest among babies less than six months old. Most of these babies are previously healthy.⁴

    The flu can lead to serious issues including:

    • Pneumonia (infection in the lungs)

    • Bronchitis (inflammation of the airways leading to the lungs)

    • Inflammation of the brain (encephalitis)

    • Inflammation of the heart (myocarditis)

    Signs that a baby is developing serious flu complications include:

    • fast breathing or breathing difficulties

    • dehydration (not drinking, producing fewer wet diapers than usual and crying without making tears)

    • being drowsy, not waking up, or not being responsive

    • being inconsolable or so irritable that the child does not even want to be held

    • having severe vomiting

    • having seizures

  • During pregnancy, your body goes through many changes to nourish a growing baby. You are now breathing for two and pumping blood for two. Your lungs and heart are working harder to make sure you and your baby both get what you need. These changes can make it harder for your body to fight infections. This means you are more likely to get very sick from the flu, even if you are otherwise healthy.

    • Pregnant people who get the flu are more than twice as likely as other adults to have a serious complication and go to the hospital.⁵

    • The risk of complications is even higher for those with pre-existing health issues.⁶

    • A serious flu infection can also increase the chances of premature birth (birth before 37 weeks of pregnancy).⁷

  • Every year, the flu causes many hospitalizations and deaths in Canada. On average, about 12,200 people are hospitalized, and approximately 3,500 people die due to the flu and its complications.¹

    While you can catch the flu at any time, it is more common in winter and early spring. Getting vaccinated is the best way to protect yourself and your newborn baby from the flu.

  • Getting a flu vaccine during pregnancy is the best way to protect your new baby from this common virus. Babies can’t get their own flu vaccine until they are six months old. Until then, the vaccine you get during pregnancy will give your baby the best early protection from the flu virus.

    See video: How Vaccines Protect Moms and Babies

About the Flu Vaccine

In Canada, it's recommended that all pregnant individuals receive the inactivated flu vaccine. It is given in one needle in your arm. This vaccine protects against four specific flu virus types each season.⁸

It’s important to get a flu vaccine every year. This is because the flu virus changes regularly, and different strains of the virus may be present in different flu seasons. Each year, Health Canada follows the recommendations of the World Health Organization (WHO) to decide which strains should be included in the vaccine to provide the best protection.⁸˒⁹

You can get the flu vaccine any point during pregnancy, starting in the first trimester. The flu vaccine is updated every year to fight new strains of the virus, so it’s important to get the updated seasonal flu vaccine once it’s available. Talk to your healthcare provider for more information about the best time to get the flu vaccine.

  • The flu vaccine is like a “practice run” for your immune system. It teaches your body how to recognize and fight off the flu virus before it can make you sick. It works by giving your body a harmless “preview” of the flu virus, which helps it learn to defend against the real thing.

    Here’s how it works:

    • The vaccine introduces your body to inactivated (dead) parts of the flu virus, called antigens. These antigens are safe because they're not alive – they’ve been killed or “switched off.”

    • These dead antigens allow your body to safely practice recognizing and fighting off the virus without giving you the actual flu.

    • Your body reacts to these dead antigens the same way it would to the real, live flu virus. It makes protective antibodies and memory cells.

    • These protective antibodies and memory cells will remember and attack the real flu virus if you ever get it in the future. It usually takes about one to two weeks after receiving the vaccine for your body to start producing these protective antibodies. When you're pregnant, this process can take slightly longer.

    You can get the flu vaccine at any point during pregnancy, starting in the first trimester. Keep in mind that the flu vaccine is updated every year to fight new strains (types) of the virus. It’s important to get an updated flu vaccine each year. Talk to your healthcare provider about the best time to get the flu vaccine.

    See video: How Vaccines Protect Moms and Babies

    See infographic: How Flu and Tdap Vaccines Work

  • The flu vaccine works by teaching your body to create protective antibodies that fight off the flu virus. When you're pregnant, these antibodies are passed through the placenta to your baby. This gives your baby protection against the flu during the first few months of life, until they are old enough to get their own vaccines. Babies can’t get their own flu vaccine until they are six months old. Until then, the vaccine you get during pregnancy gives them the best early protection against the flu.

    It’s important to know that only the protective antibodies your body makes pass to your baby in significant amounts. These antibodies help protect your baby when they need it the most until they are old enough to get their own vaccines.

    Vaccine ingredients stay near the injection site, in your muscle and lymphatic system. Once the vaccine has finished training your immune system to defend against the flu virus, your body will naturally break down and get rid of the vaccine ingredients, just like it gets rid of other materials it doesn’t need anymore. The vaccine ingredients are out of your body after several weeks.

    See video: How Vaccines Protect Moms and Babies

    See infographic: How Flu and Tdap Vaccines Work

    • Data from around the world shows that getting a flu vaccine during pregnancy can cut your chances of getting the flu nearly in half.10-13

    • The flu vaccine also lowers your chances of getting so sick that you end up in the emergency room or hospital. Studies have shown that getting vaccinated can cut your risk of being hospitalized with the flu nearly in half.14-15

  • Very effective! Babies whose parent received a flu vaccine during pregnancy are:

    • 86% less likely to catch influenza (flu) in the first two months of life.16

    • 90% less likely to be hospitalized with the flu in the first six months of life.17

    These findings show that getting vaccinated during pregnancy helps protect your baby during the first months of life when they’re most vulnerable to getting very sick and still too young to get their own flu vaccine.

    See infographic: Flu Vaccine: Benefits & What to Expect 

Getting vaccinated in pregnancy is the best way to protect both you and your baby from the flu.

Flu Vaccine Safety

  • Yes, the inactivated flu vaccine is safe for pregnant people and their babies.

    The inactivated flu vaccine can’t give you the flu or cause any harm to you or your baby because it does not contain a ‘live’ virus.

    Vaccines that do contain a ‘live’ virus, like the MMR (measles-mumps-rubella) vaccine are not recommended to pregnant people because of a theoretical risk to developing babies.

    See video: How Vaccines Protect Moms and Babies

    See infographic: How Flu and Tdap Vaccines Work

  • No, the flu vaccine does NOT increase the risk of complications (problems) during pregnancy or birth.

    Research tells us that getting the flu vaccine while pregnant PROTECTS pregnant people and babies from catching the flu and from hospitalization with flu-related complications. Studies18-24 show that for pregnant people vaccinated against the flu during pregnancy, there was:

    • No increase in the risk of premature birth (birth before 37 weeks of pregnancy)

    • No increase in the risk of birth defects

    • No increase in the risk of miscarriage

    • Lower rates of stillbirth among those who got the flu vaccine in pregnancy, compared to those who didn’t.

    Additionally:

    • Babies born during flu season to a parent who received the flu vaccine in pregnancy are less likely to be premature (born before 37 weeks of pregnancy), small for their gestational age, or have low birth weight.23

    • Studies of children older than six months of age found no link between flu vaccination in pregnancy and negative childhood health outcomes (including atopic, autoimmune, and neurodevelopmental outcomes).22-24

  • No, there's no chance that you or your baby will catch the flu from the vaccine. That's because the vaccine does not contain a 'live' virus.

    Instead, the flu vaccine given during pregnancy uses what's called an 'inactivated' virus. This means it's made from a safe, dead version of the flu virus that can't make you sick or cause any harm to you or your baby.

    Vaccines that do contain ‘live’ viruses, like the MMR (measles -mumps-rubella) vaccine are not recommended to pregnant people.

  • A very small number of people have a severe allergic reaction to vaccines called ‘anaphylaxis,’ where they can develop swelling, hives, breathing difficulties, lowered blood pressure and in severe cases, shock.

    Anaphylactic reactions are very rare – they occur in about one in a million people who have a vaccination.25 In the rare cases where someone does have an anaphylactic reaction, it usually happens shortly after they get a vaccine. This is why you are asked to wait at least 15 minutes after getting a vaccine before leaving a clinic or pharmacy. Healthcare providers are trained to respond to an anaphylactic reaction.

    See infographic: Flu Vaccine: Benefits & What to Expect

  • The only medical reason for not getting the flu vaccine is if you've had a severe allergic reaction to a part of the flu vaccine in the past. If you've experienced an allergic reaction to the flu shot before, make sure to discuss it with your healthcare provider.

Vaccine Reactions

After getting vaccinated, some people may experience temporary side effects that typically last from a few hours to a few days.

It’s important to keep in mind that experiencing some mild symptoms after getting vaccinated is perfectly normal. These symptoms are a sign that your body is working to build immunity (protection) against the disease.

Most people who have the flu vaccine have no reaction at all. Some people have mild reactions that last between 12 and 24 hours and are easily treated at home.

Doctor with gloves places a bandaid on a woman's arm after vaccination.

  • About three in every 100 women get some redness or soreness at the spot where the needle went in.26 This is called a ‘local reaction’.

    The redness and soreness will get better in a day or two. In the meantime, you can put a cool, damp cloth on the spot to soothe it, or take an over-the-counter pain medication, such as acetaminophen (Tylenol) if you feel you need to. Make sure to check with your healthcare provider before taking any other pain medications.

    See infographic: Flu Vaccine: Benefits & What to Expect 

  • Around four in every 100 women experience a headache after vaccination.26 The headache will get better by itself, but you can take over-the-counter pain medication, such as acetaminophen (Tylenol), if you feel you need to.

    See infographic: Flu Vaccine: Benefits & What to Expect 

  • Around two in every 100 women will develop a fever of around 38.5°C or less.26 If you have a fever after your vaccination, drink plenty of water and consider using some acetaminophen (Tylenol) to help bring the temperature down.

    See infographic: Flu Vaccine: Benefits & What to Expect 

  • Research shows that getting the flu vaccine in pregnancy does NOT increase the risk of pregnancy complications like miscarriage, premature birth, or stillbirth.

    Serious reactions to vaccination during pregnancy are also very rare. Very few women (around 3 in every 1,000) experience a reaction serious enough to attend a hospital emergency department.26 When they do happen, they are usually resolved with treatment from healthcare professionals or at a hospital, with both mother and baby returning to full health.

    A very small number of people have a severe allergic reaction to vaccines, called ‘anaphylaxis,’ which can cause swelling, hives, breathing difficulties, lowered blood pressure and, in severe cases, shock. Anaphylactic reactions are very rare – they occur in about one in a million people who have a vaccination.26 In the very rare cases that an anaphylactic reaction happens after a vaccination, it happens shortly after the vaccine is received. That is why you will be asked to wait for 15 minutes after getting a vaccine before leaving a clinic or pharmacy. Healthcare providers are trained to respond to an anaphylactic reaction.

    If you develop any serious symptoms, call emergency services right away by dialling 911.

    See infographic: Flu Vaccine: Benefits & What to Expect 

  • If your symptoms last longer than a couple of days, or if you are worried about how you feel after your vaccination, you can call your doctor or get help by calling the toll-free health information and advice phone service available in your province/territory:

    British Columbia, Alberta, Saskatchewan, Ontario, Quebec, New Brunswick, Nova Scotia, Newfoundland and Labrador, New Brunswick, Prince Edward Island, the Yukon, the Northwest Territories: Call 811

    Manitoba: Call 1-888-315-9257

    Nunavut: Call 211

    You can also get help by visiting your nearest emergency department or urgent care centre. If you develop any serious symptoms that you think could be an allergic reaction after your vaccination, call emergency services right away by dialling 911.

    See infographic: Flu Vaccine: Benefits & What to Expect 

Vaccine Timing

  • You can get a flu vaccine at any point during your pregnancy, and at any time of year.

    However, keep in mind that flu virus strains (types) change from year to year. As a result, flu vaccines are updated each year to protect against new flu types. It’s important to get your updated flu vaccine as soon as it’s available. Updated flu vaccines are usually available starting in early to mid-fall each year. You can also get your flu vaccine at the same time as other vaccines, like Tdap and COVID-19.

    Talk to your healthcare provider about the best time to get the flu vaccine.

  • Everyone, including pregnant people, should get vaccinated each year to boost their protection against the flu.

    Flu virus strains (types) change from year to year. This means that the flu vaccine you had previously may not protect against the flu strains that are currently going around in the community.27 Flu vaccines are updated each year to protect against new flu types, so it’s important to get your updated flu vaccine as soon as it’s available. Updated flu vaccines are usually available starting in early to mid-fall each year. Talk to your healthcare provider about the best time to get the flu vaccine.

  • Choosing to wait until after your baby is born to get the flu vaccine means your baby won't be protected against the flu at birth. If you get vaccinated while breastfeeding, your baby will get some antibodies from your breastmilk, but this protection isn't as strong as the protection they would get from the antibodies that cross the placenta during pregnancy.

    Your body also takes a couple of weeks to make these protective antibodies after you get the vaccine. This means your baby won’t have this extra layer of protection for at least the first few weeks after you give birth.

    This is why flu, Tdap and COVID-19 vaccines are highly recommended during pregnancy. The protective antibodies that your body makes are passed to your baby through the placenta, giving them protection starting the moment they’re born.

    Remember, protection for YOU means protection for TWO!

  • Yes. It is safe to get both the flu vaccine and the Tdap vaccine at the same time.28 It is also safe to get the flu vaccine and the COVID-19 vaccine at the same time.

Additional Information

  • The best way to protect your baby against the flu after they’re born is by getting the flu vaccine during pregnancy.

    You can also protect your new baby by making sure that everyone who'll be close to them, like your partner, the baby's siblings, grandparents, and anyone else who will help take care of them, is vaccinated too.

    It’s also a good idea to keep small babies away from people who are sick, and to encourage anyone in the household who is sick to cover their mouth when they cough or sneeze, and to wash their hands regularly.

  • An annual flu vaccine is recommended for everyone aged six months and over.⁹ Getting vaccinated is especially important in households with newborns, because babies that are 0-6 months old are at a greater risk of serious flu complications.

    Talk to your healthcare provider about the flu vaccine for other members of your family.

  • Depending on where you live, you can get a flu vaccine at your local pharmacy. Your healthcare provider may also offer vaccinations. It is recommended to check with your local health department or healthcare provider for more information on where to get a flu vaccination in your area.

    Find information on where to receive a flu vaccine in your province:

    Alberta

    British Columbia

    Manitoba

    New Brunswick

    Newfoundland and Labrador

    Northwest Territories

    Nova Scotia

    Nunavut

    Ontario

    Prince Edward Island

    Quebec

    Saskatchewan

    Yukon

“We all want to do what we can to protect our precious babies, and getting the vaccine was one of the ways I could do that.”

– Carly (Mom, Calgary A.B)

Key Facts

  • Influenza (flu) is a contagious virus that can be very serious for pregnant people and small babies.

  • Pregnant people and babies under six months old are at higher risk for flu-related complications, hospitalization, and even death.

  • The flu vaccine is safe and effective for both pregnant people and their babies.

  • Getting the flu vaccine during pregnancy helps protect both you and your baby from the flu.

  • When you have the flu vaccine during pregnancy, the antibodies produced by your body will cross the placenta to give your baby protection against the flu, too.

  • You can get the flu vaccine at any point during your pregnancy, and at any time of the year.

  • The flu vaccine is free for all pregnant people in Canada, every time they are pregnant.

    1. Public Health Agency of Canada. The flu (influenza) for health professionals [Internet]. 2023 [cited 2024 Oct 4]. Available from: https://www.canada.ca/en/public-health/services/diseases/flu-influenza/health-professionals.html

    2. Public Health Agency of Canada. Public funding for influenza vaccination by province/territory [Internet]. 2023 [cited 2024 Oct 4]. Available from: https://www.canada.ca/en/public-health/services/provincial-territorial-immunization-information/public-funding-influenza-vaccination-province-territory.html

    3. Li-Kim-Moy J, Yin JK, Patel C, Beard FH, Chiu C, Macartney KK, McIntyre PB. Australian vaccine preventable disease epidemiological review series: Influenza 2006 to 2015. Commun Dis Intell Q Rep. 2016;40(4)

    4. Shang M, Blanton L, Brammer L, Olsen SJ, Fry AM. Influenza-associated pediatric deaths in the United States, 2010-2016. Pediatrics. 2018;141(4). doi:10.1542/peds.2017-2918

    5. Mertz D, Geraci J, Winkup J, et al. Pregnancy as a risk factor for severe outcomes from influenza virus infection: A systematic review and meta-analysis of observational studies. Vaccine. 2017;35(4):521-8. doi: 10.1016/j.vaccine.2016.12.012

    6. Dodds L, McNeil SA, Fell DB, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ. 2007;176(4):463-8. Doi: 10.1503/cmaj.061435

    7. Fell DB, Savitz DA, Kramer MS, et al. Maternal influenza and birth outcomes: systematic review of comparative studies. BJOG. 2017;124(1):48-59. DOI: 10.1111/1471-0528.14143

    8. Public Health Agency of Canada. Get your flu shot [Internet]. 2021 [cited 2024 Oct 4]. Available from: https://www.canada.ca/en/public-health/services/diseases/flu-influenza/get-your-flu-shot.html

    9. Public Health Agency of Canada. Canadian Immunization Guide: Statement on seasonal influenza vaccine for 2022-2023 [Internet]. 2022 [cited 2024 Oct 4]. Available from: https://www.canada.ca/en/public-health/services/publications/vaccines-immunization/canadian-immunization-guide-statement-seasonal-influenza-vaccine-2022-2023.html#a8

    10. Omer S. Maternal immunization. N Engl J Med. 2017;376(25):2497. DOI: 10.1056/NEJMra1509044

    11. Steinhoff MC, Katz J, Englund JA, et al. Year-round influenza immunisation during pregnancy in Nepal: a phase 4, randomised, placebo-controlled trial. Lancet Infect Dis. 2017;17(9):981-9. DOI: 10.1016/S1473-3099(17)30252-9

    12. Madhi SA, Cutland CL, Kuwanda L, et al. Influenza vaccination of pregnant women and protection of their infants. N Engl J Med. 2014;371(10):918-31. DOI: 10.1056/NEJMoa1401480

    13. Omer SB, Clark DR, Madhi SA, et al. Efficacy, duration of protection, birth outcomes, and infant growth associated with influenza vaccination in pregnancy: a pooled analysis of three randomised controlled trials. Lancet Respir Med. 2020;8(6):597-608. DOI: 10.1016/S2213-2600(19)30479-5

    14. Regan AK, Klerk N, Moore HC, et al. Effectiveness of seasonal trivalent influenza vaccination against hospital-attended acute respiratory infections in pregnant women: A retrospective cohort study. Vaccine. 2016;34(32):3649-56. DOI: 10.1016/j.vaccine.2016.05.032

    15. Thompson MG, Kwong JC, Regan AK, et al. Influenza vaccine effectiveness in preventing influenza-associated hospitalizations during pregnancy: A multi-country retrospective test negative design study, 2010-2016. Clin Infect Dis. 2019;68(9):1444-53. DOI: 10.1093/cid/ciy737

    16. Nunes MC, Cutland CL, Jones S, et al. Duration of infant protection against influenza illness conferred by maternal immunization: Secondary analysis of a randomized clinical trial. JAMA Pediatr. 2016;170(9):840-7. DOI: 10.1001/jamapediatrics.2016.0921

    17. Benowitz I, Esposito DB, Gracey KD, Shapiro ED, Vázquez M. Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis. 2010;51(12):1355-61. DOI: 10.1086/657309

    18. Fell DB, Platt RW, Lanes A, et al. Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. BJOG. 2015;122(1):17-26. DOI: 10.1111/1471-0528.12977

    19. McMillan M, Porritt K, Kralik D, Costi L, Marshall H. Influenza vaccination during pregnancy: a systematic review of fetal death, spontaneous abortion, and congenital malformation safety outcomes. Vaccine. 2015;33(18):2108-17. DOI: 10.1016/j.vaccine.2015.02.068

    20. Regan AK, Moore HC, de Klerk N, et al. Seasonal trivalent influenza vaccination during pregnancy and the incidence of stillbirth: Population-based retrospective cohort study. Clin Infect Dis. 2016;62(10):1221-7. DOI: 10.1093/cid/ciw082

    21. McHugh L, Andrews R, Lambert S, et al. Birth outcomes for Australian mother-infant pairs who received an influenza vaccine during pregnancy, 2012-2014: The FluMum study. Vaccine. 2017;35(10):1403-9. DOI: 10.1016/j.vaccine.2017.01.075

    22. Foo DYP, Sarna M, Pereira G, Moore HC, Fell DB, Regan AK. Early childhood health outcomes following in utero exposure to influenza vaccines: A systematic review. Pediatrics. 2020;146(2). doi:10.1542/peds.2020-0375

    23. Public Health Agency of Canada. Immunization in pregnancy and breastfeeding: Canadian Immunization Guide [Internet]. [cited 2024 Oct 4]. Available from: https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-3-vaccination-specific-populations/page-4-immunization-pregnancy-breastfeeding.html

    24. Ludvigsson JF, Winell H, Sandin S, et al. Maternal influenza A(H1N1) immunization during pregnancy and risk for autism spectrum disorder in offspring. Ann Intern Med. 2020;172(7):502-11. DOI: 10.7326/M20-0167

    25. McNeil MM, Weintraub ES, Duffy J, et al. Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol. 2016;137(3):868-78. DOI: 10.1016/j.jaci.2015.07.048

    26. Regan AK, Tracey LE, Blyth CC, Richmond PC, Effler PV. A prospective cohort study assessing the reactogenicity of pertussis and influenza vaccines administered during pregnancy. Vaccine. 2016;34(20):2299-304. https://doi.org/10.1016/j.vaccine.2016.03.084

    27. Ferdinands JM, Fry AM, Reynolds S, et al. Intraseason waning of influenza vaccine protection: Evidence from the US Influenza Vaccine Effectiveness Network, 2011-12 through 2014-15. Clin Infect Dis. 2017;64(5):544-50. DOI: 10.1093/cid/ciw816

    28. Centers for Disease Control and Prevention. Making a strong vaccine referral to pregnant women [PDF]. [cited 2024 Oct 4]. https://www.cdc.gov/pertussis/downloads/fs-hcp-tdap-vaccine-referral.pdf