Influenza Vaccine
Learn how getting a seasonal influenza (flu) vaccine helps protect you and your baby from serious illness caused by the flu virus.
Quick Facts
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Influenza is a common virus that spreads easily.
Influenza (flu) is a common virus that spreads through coughs, sneezes, and close contact. It can cause fever, chills, cough, and body aches, and can lead to serious illness in pregnant people and babies.
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Pregnant people and babies are at higher risk.
During pregnancy, changes to your heart, lungs, and immune system make you more likely to get very sick from the flu. Babies under 6 months are also at higher risk of flu complications and can’t get their own flu shot yet.
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The flu vaccine is recommended for all pregnant people.
The inactivated flu vaccine is recommended for all pregnant people at any stage of pregnancy. It’s free for pregnant people in Canada and available at doctor’s offices, pharmacies, and public health clinics.
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Getting vaccinated helps protect you.
Getting the flu vaccine during pregnancy lowers your risk of catching the flu, reduces your chances of serious illness, and helps prevent complications like pneumonia and hospitalization.
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Getting vaccinated helps protect your baby.
When you get vaccinated, your body makes protective antibodies that pass to your baby through the placenta. These antibodies help protect your baby for the first few months of life until they can get their own vaccine.
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The flu vaccine is safe for you and your baby.
The flu vaccine is safe for you and your baby. It does not increase the risk of miscarriage, preterm birth, or any other complications during pregnancy or birth.
About Influenza (Flu)
Influenza, or the flu, is a contagious virus that spreads easily through coughs, sneezes, talking, or by touching shared surfaces. Each year in Canada, the flu leads to about 12,200 hospitalizations and 3,500 deaths.¹
Flu symptoms often come on suddenly and can include fever, chills, cough, sore throat, muscle aches, and extreme tiredness.² In some cases, the flu can lead to dehydration or serious complications like pneumonia or bronchitis.
While many people recover at home in a few days, the flu can be severe or even life-threatening for pregnant people and young babies, who are more vulnerable to complications.
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When someone with the flu coughs, sneezes, or even talks, they release tiny droplets into the air. If you breathe in those droplets—or touch a surface where they landed and then touch your face—you can catch the flu.
Because the virus spreads so easily, it can move quickly through households, daycares, and workplaces.
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Babies, especially those under six months, are more likely to get very sick from the flu. They face a higher risk of serious complications and are more likely than older children to need hospital care.2,3 Sadly, flu-related deaths are highest among babies under six months old.2,3 That’s why it’s so important to protect your baby during their first few months of life.
The flu can cause serious complications in young babies, including:
Pneumonia – a lung infection that makes it hard to breathe
Bronchitis – swelling in the airways that causes coughing and wheezing
Encephalitis – swelling in the brain, which can affect movement or thinking
Myocarditis – inflammation of the heart muscle, which can be life-threatening
Babies can’t get their own flu vaccine until they’re 6 months old. Until then, the flu vaccine you get during pregnancy is the best way to protect your baby from the flu in the first few months after they are born.
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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.4
The risk of complications is even higher for those with pre-existing health issues.5
A serious flu infection can also increase the chances of premature birth (birth before 37 weeks of pregnancy).6
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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 from 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.
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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, the inactivated flu vaccine is recommended for all pregnant people to help protect against seasonal influenza. It is given as a single shot in the arm and is safe to receive at any stage of pregnancy, starting in the first trimester.
It’s important to get the flu vaccine every year. The flu virus changes over time, and different strains (types) can spread each season. To keep up with these changes, the flu vaccine is reviewed and updated every year to protect against the most common strains.⁷ Talk to your healthcare provider for more information about the best time to get the flu vaccine.
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The flu vaccine acts like a practice run for your immune system. It helps your body learn how to recognize and fight off the flu virus before it has a chance to make you sick.
Here’s how it works:
The vaccine contains dead (inactivated) pieces of the flu virus, called antigens. These antigens are completely harmless and cannot give you or your baby the flu.
After you get the vaccine, your immune system recognizes the antigens as something unfamiliar and starts building a defence. It produces special proteins called antibodies that know how to find and destroy the flu virus.
If you come into contact with the flu virus in the future, your immune system will respond quickly, helping to stop the infection and protect you from getting seriously ill.
It usually takes about two weeks after getting the flu vaccine for your body to build up protection. If you're pregnant, this process might take a little 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
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The flu vaccine works by triggering your body to create protective antibodies that fight off the flu virus. During pregnancy, these protective antibodies pass through the placenta to your baby. This gives them early protection against the flu during their first few months of life, when they are most vulnerable to serious illness.
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.
See video: How Vaccines Protect Moms and Babies
See infographic: How Flu and Tdap Vaccines Work
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Research shows that getting the flu vaccine during pregnancy is a highly effective way to protect both you and your baby from serious illness and hospitalization.
For pregnant people: Studies show that people who get the flu shot during pregnancy are less likely to catch the flu and less likely to end up in the hospital compared to those who are not vaccinated.
A review of many studies found that the flu vaccine can cut your chances of getting the flu nearly in half.8-10
Getting vaccinated also protects you from serious illness: people who get the flu shot during pregnancy are about 40% less likely to be hospitalized with the flu.11,12
For babies: The flu vaccine also protects your baby in their first months of life, when they are most vulnerable and too young to get their own flu shot.
Babies whose parent received a flu vaccine during pregnancy are around 86% less likely to catch the flu in their first 2 months.13
They are also about 90% less likely to be hospitalized with the flu in their first 6 months.14
This protection is especially important because babies can’t get their own flu shot until they’re 6 months old. Getting vaccinated during pregnancy helps keep them safe during those first few months when they’re most vulnerable.
See infographic: Flu Vaccine: Benefits & What to Expect
When you get vaccinated during pregnancy, you pass protective antibodies to your baby, helping keep them safe from common infections after they are born.
Flu Vaccine Safety
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Yes, the inactivated flu vaccine (the flu shot) is safe and recommended at any stage of pregnancy. It has been given to millions of pregnant people around the world over many years and has been shown to be safe for both the pregnant person and their baby.
The flu shot is made with an inactivated (killed) virus, which means it cannot give you the flu. Because it does not contain live virus, it cannot infect you or your baby, and it does not increase the risk of birth defects, miscarriage, or pregnancy complications.
The nasal spray flu vaccine, on the other hand, is a live attenuated vaccine, meaning it contains a weakened form of the flu virus. While this version of the vaccine is safe for most healthy children and adults, it is not recommended during pregnancy.
See video: How Vaccines Protect Moms and Babies
See infographic: How Flu and Tdap Vaccines Work
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No. Getting the flu vaccine during pregnancy does not increase the risk of pregnancy complications. In fact, research shows that getting the flu vaccine while pregnant helps protect both you and your baby from serious illness and flu-related hospitalization.
Studies of people who got the flu vaccine during pregnancy have found:15-19
No increased risk of preterm birth (before 37 weeks)
No increased risk of birth defects or miscarriage
No difference in average birth weight or due date
Lower rates of stillbirth compared to those who weren’t vaccinated
Getting the flu vaccine during pregnancy may also help your baby get a healthier start in life. One study found that babies born during flu season to a vaccinated parent are less likely to have low birth weight or to be small for their gestational age.20
There’s also no evidence of long-term health concerns for children whose parents received the flu vaccine during pregnancy. Studies have found no link between the flu shot and conditions like asthma, autoimmune diseases, or developmental issues later in childhood.21,22
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No. You and your baby cannot catch the flu from the flu vaccine.
The flu shot given during pregnancy is made with an inactivated (or "killed") virus, which means it can’t make you sick. It does not contain any live virus, so there’s no risk of you or your baby getting the flu from the vaccine.
Vaccines that do contain live viruses—like the MMR (measles, mumps, rubella) vaccine—are not recommended during pregnancy as a precaution.
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Serious side effects from the flu vaccine are extremely rare.
One rare reaction is called anaphylaxis—a severe allergic reaction that can cause symptoms like swelling, hives, and trouble breathing.
Anaphylaxis happens in about one in a million people who get a vaccine.23
When it does occur, it usually happens within minutes of the vaccine being given. That’s why you're asked to stay at the clinic or pharmacy for at least 15 minutes after getting vaccinated—so that trained healthcare providers can act quickly if needed.
See infographic: Flu Vaccine: Benefits & What to Expect
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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 short-term side effects that usually 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 12–24 hours and can be easily treated at home.
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Many people who get the flu shot during pregnancy don’t experience any side effects. When side effects do happen, they’re usually mild and go away on their own within a day or two.
Common side effects include:
Redness or soreness at the injection site: About 3 out of every 100 people experience some redness, tenderness, or soreness where the needle went in.24 This is known as a local reaction, and it’s a normal sign that your body is building protection. You can help relieve any soreness by applying a cool, damp cloth to the area or taking an over-the-counter pain reliever, such as acetaminophen (Tylenol), if needed.
Headache: Around 4 out of every 100 people experience a headache after vaccination.24 It will usually go away on its own within a day or two. If needed, you can take acetaminophen (Tylenol) to help you feel more comfortable.
Mild fever: About 2 out of every 100 people develop a low-grade fever (around 38.5°C or less) after vaccination.24 If this happens, drink plenty of fluids and consider taking acetaminophen (Tylenol) to help bring your temperature down and make you more comfortable. If you feel very unwell or your fever doesn’t go away, contact your healthcare provider.
Always check with your healthcare provider before taking any pain medications during pregnancy.
See infographic: Flu Vaccine: Benefits & What to Expect
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Serious reactions to the flu vaccine during pregnancy are very rare.
Around 3 in every 1,000 people experience a reaction serious enough to go to the emergency department.24 When this happens, symptoms are usually treated quickly by healthcare professionals, and both the parent and baby recover fully.
A very small number of people may have a severe allergic reaction, called anaphylaxis. This is an extremely rare condition—occurring in about one in a million people who receive a vaccine.24 Anaphylaxis can cause symptoms like swelling, hives, difficulty breathing, low blood pressure, or (in rare cases) shock. These reactions usually happen within minutes of getting the vaccine, which is why you are asked to stay at the clinic or pharmacy for 15 minutes after your shot. Healthcare providers are trained to manage these reactions immediately if they occur.
If you develop any serious symptoms after your vaccination, call emergency services right away by dialling 911.
See infographic: Flu Vaccine: Benefits & What to Expect
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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
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You can get a flu vaccine at any point during your pregnancy, and at any time of year.
Keep in mind that flu viruses change from year to year, so the flu vaccine is updated each year to protect against the most common types expected during the upcoming flu season.
To get the best protection, it’s a good idea to get your updated flu shot as soon as it’s available, which is usually in early to mid-fall each year.
You can also get your flu shot at the same time as other recommended vaccines, such as Tdap and COVID-19 vaccines.
If you’re unsure about timing, talk to your healthcare provider about the best time to get vaccinated based on your due date and flu season in your area.
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Yes. Everyone, including pregnant people, should get a flu vaccine each year to stay protected.
Flu viruses change from year to year, so the vaccine you received in the past may not protect you against the strains that are spreading this year.25
That’s why flu vaccines are updated every year to match the most common types of flu expected during the upcoming season.
To get the best protection, it’s important to get your updated flu shot as soon as it becomes available, which is usually in early to mid-fall.
Talk to your healthcare provider about the best time to get the flu vaccine.
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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, RSVpreF 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!
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Yes. It’s safe to get the flu vaccine at the same time as other recommended vaccines during pregnancy, including Tdap and COVID-19 vaccines. This helps you stay protected without needing multiple visits. If you have any questions or concerns, talk to your healthcare provider.
Additional Information
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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.
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Yes. It’s recommended that everyone aged six months and older gets a flu vaccine every year.26
Getting vaccinated is especially important in households with newborns, because babies under 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.
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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:
Carly (Mom, Calgary, AB)
“We all want to do what we can to protect our babies, and getting the vaccine was one of the ways I could do that.”
Key Facts
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1. Public Health Agency of Canada. Flu (influenza): For health professionals [Internet] Ottawa, ON: Government of Canada; 2024 [updated Oct 7]. Available from: https://www.canada.ca/en/public-health/services/diseases/flu-influenza/health-professionals.html.
2. Macdonald N, Bortolussi R. Protecting young babies from influenza. Paediatr Child Health. 2009;14(9):612-7. 10.1093/pch/14.9.612.
3. Shang M, Blanton L, Brammer L, Olsen SJ, Fry AM. Influenza-Associated Pediatric Deaths in the United States, 2010-2016. Pediatrics. 2018;141(4). 10.1542/peds.2017-2918.
4. Mertz D, Geraci J, Winkup J, Gessner BD, Ortiz JR, Loeb M. 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. 10.1016/j.vaccine.2016.12.012.
5. Dodds L, McNeil SA, Fell DB, Allen VM, Coombs A, Scott J, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ Canadian Medical Association Journal. 2007;176(4):463-8.
6. Fell DB, Savitz DA, Kramer MS, Gessner BD, Katz MA, Knight M, et al. Maternal influenza and birth outcomes: systematic review of comparative studies. Bjog. 2017;124(1):48-59. 10.1111/1471-0528.14143.
7. Public Health Agency of Canada. Flu (influenza): Get your flu vaccine (flu shot) [Internet] Ottawa, ON: Government of Canada; 2025 [updated Jan 20, 2025]. Available from: https://www.canada.ca/en/public-health/services/diseases/flu-influenza/get-your-flu-shot.html?utm_source=during-pregnancy-page&utm_medium=learn-more-link&utm_content=flu-vaccine&utm_campaign=hc-sc-seasonalflu-21-22.
8. Omer SB, Clark DR, Madhi SA, Tapia MD, Nunes MC, Cutland CL, 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. 10.1016/s2213-2600(19)30479-5.
9. Thompson MG, Li DK, Shifflett P, Sokolow LZ, Ferber JR, Kurosky S, et al. Effectiveness of seasonal trivalent influenza vaccine for preventing influenza virus illness among pregnant women: a population-based case-control study during the 2010-2011 and 2011-2012 influenza seasons. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2014;58(4):449-57. 10.1093/cid/cit750.
10. Madhi SA, Cutland CL, Kuwanda L, Weinberg A, Hugo A, Jones S, et al. Influenza vaccination of pregnant women and protection of their infants. N Engl J Med. 2014;371(10):918-31. 10.1056/NEJMoa1401480.
11. Thompson MG, Kwong JC, Regan AK, Katz MA, Drews SJ, Azziz-Baumgartner E, et al. Influenza Vaccine Effectiveness in Preventing Influenza-associated Hospitalizations During Pregnancy: A Multi-country Retrospective Test Negative Design Study, 2010-2016. Clinical Infectious Diseases. 2019;68(9):1444-53. https://dx.doi.org/10.1093/cid/ciy737.
12. Regan AK, Klerk N, Moore HC, Omer SB, Shellam G, Effler PV. 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. 10.1016/j.vaccine.2016.05.032.
13. Nunes MC, Cutland CL, Jones S, Hugo A, Madimabe R, Simões EA, 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. 10.1001/jamapediatrics.2016.0921.
14. Benowitz I, Esposito DB, Gracey KD, Shapiro ED, Vazquez M. Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clinical Infectious Diseases. 2010;51(12):1355-61. http://dx.doi.org/10.1086/657309.
15. Fell DB, Platt RW, Lanes A, Wilson K, Kaufman JS, Basso O, et al. Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. Bjog. 2015;122(1):17-26. 10.1111/1471-0528.12977.
16. 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. 10.1016/j.vaccine.2015.02.068.
17. Regan AK, Moore HC, de Klerk N, Omer SB, Shellam G, Mak DB, et al. Seasonal Trivalent Influenza Vaccination During Pregnancy and the Incidence of Stillbirth: Population-Based Retrospective Cohort Study. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2016;62(10):1221-7. 10.1093/cid/ciw082.
18. McHugh L, Andrews RM, Lambert SB, Viney KA, Wood N, Perrett KP, 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. 10.1016/j.vaccine.2017.01.075.
19. Regan AK, Wesselink AK, Wang TR, Savitz DA, Yland JJ, Rothman KJ, et al. Risk of Miscarriage in Relation to Seasonal Influenza Vaccination Before or During Pregnancy. Obstet Gynecol. 2023;142(3):625-35.
20. Mohammed H, Roberts CT, Grzeskowiak LE, Giles LC, Dekker GA, Marshall HS. Safety and protective effects of maternal influenza vaccination on pregnancy and birth outcomes: A prospective cohort study. EClinicalMedicine. 2020;26:100522. 10.1016/j.eclinm.2020.100522.
21. Mehrabadi A, Dodds L, MacDonald NE, Top KA, Benchimol EI, Kwong JC, et al. Association of Maternal Influenza Vaccination During Pregnancy With Early Childhood Health Outcomes. Jama. 2021;325(22):2285-93. 10.1001/jama.2021.6778.
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). 10.1542/peds.2020-0375.
23. McNeil MM, Weintraub ES, Duffy J, Sukumaran L, Jacobsen SJ, Klein NP, et al. Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol. 2016;137(3):868-78. 10.1016/j.jaci.2015.07.048.
24. 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. 10.1016/j.vaccine.2016.03.084.
25. Ferdinands JM, Fry AM, Reynolds S, Petrie J, Flannery B, Jackson ML, et al. Intraseason waning of influenza vaccine protection: Evidence from the US Influenza Vaccine Effectiveness Network, 2011-12 through 2014-15. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2017;64(5):544-50. 10.1093/cid/ciw816.
26. National Advisory Committee on Immunization. Seasonal Influenza Vaccine Statement for 2022–2023. Ottawa, ON; 2022 [updated September 9, 2022]. Available from: https://www.canada.ca/en/public-health/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2022-48/issue-9-september-2022/summary-national-advisory-committee-immunization-naci-seasonal-influenza-vaccine-statement-2022-2023.html.