Influenza

Key facts

  • You can get the influenza vaccination at any time during your pregnancy, and at any time of the year. You can also have it at the same time as you have your whooping cough (pertussis) vaccination.

  • Influenza (commonly called ‘the flu’) is a highly contagious viral infection that can have serious impacts on pregnant women and infants.

  • Influenza vaccination during pregnancy is safe, and effective.

  • The influenza vaccine is free for all pregnant women in Australia, every time they are pregnant.

Last updated on 27 April 2023.

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What is influenza?

Influenza is a viral infection. Every year, around five per cent of the population1 catch influenza (although the numbers vary from year to year depending on which strains of the virus are active).

Influenza can be very severe. People aged 65 years and over, and children aged under five years, are the ones most likely to get admitted to hospital with influenza.1 Those with the highest hospitalisation rate of all are babies from newborn to five months.1

Influenza usually begins with the sudden onset of fever, chills, a headache, dry cough, sore throat and feelings of fatigue and weakness. If it progresses, influenza can also cause dehydration or complications such as pneumonia or bronchitis. More serious complications can also occur, including secondary bacterial infections, as well as heart, blood and neurological abnormalities such as inflammation of the brain (encephalitis). These conditions can be especially dangerous for pregnant women and small babies.

When someone who already has influenza coughs, sneezes or talks, they produce tiny droplets that carry the influenza virus into the air. If you breathe in those droplets you can catch influenza, too.

Yes. In 2019, more than 310,000 confirmed cases of influenza were reported in Australia, resulting in 810 deaths.2,3 While you can catch influenza at any time, it is more common in winter and early spring (around May to October).

Vaccination is the best way to protect your baby and yourself against influenza.

What happens when you catch influenza?

Pregnant women are more likely to get very sick from influenza than women who are not pregnant. Being seriously unwell while pregnant can lead to complications in your pregnancy.

Babies cannot have an influenza vaccination until they are six months or older. Until then, the vaccination you have during pregnancy is the best way to protect your baby against influenza. 

Being pregnant changes how your heart, lungs and immune system function. These changes mean you are more likely to get very sick from influenza, even if you are otherwise healthy.

Pregnant women who catch influenza are more than twice as likely as other adults to develop a serious complication and be admitted to hospital.4 This is even higher for women with underlying medical illnesses.5 Complications caused by an influenza infection include pneumonia, bronchitis, inflammation of the brain (encephalitis) and inflammation of the heart (myocarditis). A severe influenza infection can also lead to premature delivery.6

Babies, especially babies under the age of six months, are more at risk of developing serious complications from influenza and are more likely than other children to end up in hospital as a result.1 Those serious complications include pneumonia, bronchitis, inflammation of the brain (encephalitis) and inflammation of the heart (myocarditis). Influenza can also increase the risk of bacterial infection and toxins in the blood stream (sepsis).

Deaths from influenza are highest among babies less than six months old, and most are previously healthy children.7

Signs that a baby is developing flu complications include:

  • fast breathing or breathing difficulties
  • dehydration (not drinking, producing fewer wet nappies 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.
How can I protect myself and my baby from influenza?

While influenza can be very severe, there are ways to protect against this disease. Getting an influenza vaccination during pregnancy is the most effective way of protecting your baby against this common but nasty virus. Babies can’t be vaccinated against influenza until they are six months old. Until then, the vaccine you get during pregnancy will provide the best early protection from the influenza virus.

When should I be vaccinated?

You can get your influenza vaccination at any time during your pregnancy, starting in the first trimester. It is given in one needle, in your arm.

Everyone should get an influenza vaccine every year. This is because the influenza virus changes regularly, and different strains of the virus may be present in different influenza seasons. Each year, the Australian Influenza Vaccine Committee follows the recommendations of the World Health Organization (WHO) to decide which strains should be included in the vaccine to provide the best protection.  

Yes. It is safe to have both the influenza vaccine and the pertussis (or ‘whooping cough’) vaccine at the same time.

Women should be vaccinated against influenza each time they are pregnant for two important reasons.

One reason is that the influenza vaccine you had previously may not provide protection against the influenza strains that are currently active in the community. That’s because the influenza virus has an unusual ability to change its structure from year to year. In Australia, health authorities follow the recommendations of the World Health Organization (WHO) to produce a new vaccine each year to match that year’s active influenza strains.

The other reason is that the protection the vaccine provides against influenza viruses wears off as the influenza season progresses.8 Everyone, including pregnant women, should have an influenza vaccine each year to boost their immune system. 

If you choose to have the vaccine after your baby is born, your baby will not have protection against influenza at birth.

When you have the vaccine during pregnancy, the antibodies you produce are transferred across the placenta to your baby. This means that your baby will have the antibodies they need to fight the influenza virus from the day they are born.

If you have the vaccine after your baby is born, some of the antibodies you produce will be passed on to your baby through your breastmilk. This will offer some protection, but it will not be as effective as the protection provided by the antibodies that cross the placenta during pregnancy. Also, your body won’t begin producing antibodies until a few weeks after you have had the vaccination which means your baby will be unprotected for at least the first few weeks after birth.  

Babies can have their own influenza vaccination from six months of age.8

Where do I go to get vaccinated?

The midwife or trained immunisation nurse at your antenatal clinic may be able to give you an influenza  vaccination. If not, then you can go to your GP or your local council clinic. Most GPs will need you to make an appointment if you require a vaccine.

How does the influenza vaccine work?

In Australia, the influenza vaccine protects against three or four types (or ‘strains’) of the influenza virus. It works by training your body’s immune system to recognise and get rid of the influenza virus. The vaccine contains tiny fragments of the ‘inactivated’ influenza virus called ‘antigens’. Inactivated antigens cannot reproduce themselves or cause disease.

Vaccines that contain ‘live’ antigens (such as the measles, mumps and rubella vaccine also known as the MMR vaccine) are not given to women during pregnancy.

When your immune system detects the antigens in the influenza vaccine, it produces antibodies to fight them and get rid of them. Your body usually starts producing antibodies around one or two weeks after you have the vaccine. When you’re pregnant it can take a bit longer.

When you have a vaccine during pregnancy, the antibodies that your immune system produces will cross the placenta and be transferred to your baby to give your baby protection against the disease, too. The antibodies can also be passed on through your breastmilk, although the level of protection provided when antibodies pass through breastmilk is not clear.

See ‘How will the vaccine affect my baby?’ for more >

Is it safe to get the vaccine when you’re pregnant?

Yes. The influenza vaccine is safe for pregnant women and for their babies.

No. Research tells us that being vaccinated against influenza during pregnancy does not increase the risk of adverse pregnancy outcomes such as stillbirth, premature delivery, or on early childhood outcomes.9-14

Specifically:

  • There were lower rates of stillbirth among women who had an influenza vaccine in pregnancy compared to those women who did not get an influenza vaccine in pregnancy.10-12
  • There was no difference in the length of pregnancy (gestation period) for babies born to mothers who had the influenza vaccine in pregnancy and those who didn’t.10, 13
  • There was no difference in the rates of birth defects among women who had an influenza vaccine in pregnancy compared to those women who did not get an influenza vaccine in pregnancy.11
  • Studies of children older than 6 months of age did not identify an association between exposure to influenza vaccines during pregnancy and adverse childhood health outcomes (atopic, autoimmune, and neurodevelopmental outcomes).14,15

The only medical reason for a pregnant woman not to have the influenza vaccine is if she has previously had an anaphylactic reaction to a component of the influenza vaccine.

How effective is the vaccine?

The effectiveness of influenza vaccines can vary depending on which strains of the virus are present in the community, but vaccination is still the most effective way to protect yourself and your baby. It is important to get an influenza vaccine every year (and for each pregnancy) because the virus changes regularly and the vaccines protect against different strains of the virus each season.9 Each year, the Australian Influenza Vaccine Committee follows the recommendations of the World Health Organization (WHO) to decide which strains should be included in the vaccine to provide the best protection.

Around the world, having the influenza vaccine during pregnancy has been shown to reduce a mother’s chance of catching influenza by around 30 to 50 per cent.9,16-18

A recent study showed that women who had an influenza vaccination during pregnancy were 49 per cent less likely to be hospitalised with influenza-related complications.24

It has also been shown that women who had an influenza vaccination during pregnancy were 65 per cent less likely to develop acute respiratory illness that required emergency department visits and hospitalisation.25

Studies have shown that between 30 and 63 per cent of babies whose mothers were vaccinated against influenza during pregnancy were protected against influenza illness for the first six months of life.18 Importantly, protection was shown to be even higher in the first few months of life, with 86 per cent of infants protected from influenza for the first two months of life.19

Additionally, it has been shown that babies whose mothers had an influenza vaccine during pregnancy were more than 90 per cent less likely to be admitted to hospital with influenza in the first six months of life.20

Is there a risk my baby and I will catch influenza from the vaccine?

No. There is no risk that either you or your baby could catch the disease from the vaccine because it does not contain a live virus. The influenza vaccine recommended during pregnancy contains only ‘inactivated’ antigens.

Will I have a reaction to the vaccine?

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

If your symptoms last longer than a couple of days, or if you are worried about how you feel after your vaccination, you can get help from your doctor, or your nearest emergency department, or by calling Health Direct on 1800 022 222.

Some women get some redness and soreness at the spot where the needle went in21 (this is called a ‘local reaction’).

  • Around three in 100 women who have an influenza vaccination during pregnancy experience a local reaction.21
    Around seven in 100 women who have a whooping cough vaccination during pregnancy experience a local reaction.21

The redness and soreness will get better in a day or two. In the meantime, you can place a cool, damp cloth on the spot to soothe it, and you can take an over-the-counter pain medication, such as paracetamol, if you feel you need one. You should check with your doctor before taking any other pain medications.

Some women experience a headache after vaccination.21

  • Around four in 100 women experience a headache after having an influenza vaccination.21
  • Around three in 100 women experience a headache after having a whooping cough vaccination.21

The headache will get better by itself, but you can take an over-the-counter pain medication, such as paracetamol, if you feel you need one.

Some women develop a fever of 38.5°C or less.21 A high fever (above 39°) is very uncommon.

Around two in 100 women experience a fever of around 38 degrees or less after having an influenza vaccination.21
Around two in 100 women experience a fever of around 38 degrees or less after having a whooping cough vaccination.21

If you have a fever after your vaccination, drink plenty of water and consider using some paracetamol to help bring the temperature down.

Very few women (around three in every 1,000) experience a reaction serious enough to require them to attend a hospital emergency department.21 Follow-up with those women indicated that all symptoms resolved and that both mother and baby remained healthy.

Are there any rare and/or serious effects to the influenza vaccine?

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.22 Midwives, nurses and GPs are trained to respond to an anaphylactic reaction with quick delivery of adrenaline.

What else can I do to protect my child from influenza?

Having an influenza vaccine during pregnancy is the best way to protect your baby against influenza.

You can also help protect small babies from getting influenza by making sure that everyone around them has been vaccinated. This could include your partner, the baby’s siblings, grandparents and other people who will be helping to care for the baby, such as nannies.

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

An annual influenza vaccination is recommended for everyone aged six months and over23. It’s even more important in households with small babies because they are at a greater risk of suffering from serious influenza complications. Talk to your doctor about influenza vaccination for other members of your family. The vaccine is free for certain high-risk groups and for children aged between six months and five years. 

The development of this content was led by the Murdoch Children's Research Institute for the MumBubVax website (now archived).


  1. Li-Kim-Moy, J., Yin, J.K., Patel, C., et al., Australian vaccine preventable disease epidemiological review series: Influenza 2006 to 2015. Commun Dis Intell Q Rep, 2016. 40(4): p. E482-E495.
  2. Australian Government Department of Health. National Notifiable Diseases Surveillance System. [cited 2020 August ]; Available from: http://www9.health.gov.au/cda/source/rpt_4.cfm. 
  3. Australian Government Department of Health. Australian Influenza Surveillance Report No. 12 | 23 September to 06 October 2019. 2019 [cited 2020 August ]; Available from: https://www.health.gov.au/resources/collections/australian-influenza-surveillance-reports-2019
  4. 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): p. 521-528.
  5. Dodds, L., McNeil, S.A., Fell, D.B., 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): p. 463-8.
  6. Fell, D.B., Savitz, D.A., Kramer, M.S., et al., Maternal influenza and birth outcomes: systematic review of comparative studies. Bjog, 2017. 124(1): p. 48-59.
  7. Shang, M., Blanton, L., Brammer, L., Olsen, S.J., and Fry, A.M., Influenza-Associated Pediatric Deaths in the United States, 2010-2016. Pediatrics, 2018. 141(4).
  8. Ferdinands, J.M., Fry, A.M., 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): p. 544-550. 
  9. Omer, S.B., Clark, D.R., Madhi, S.A., 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): p. 597-608.
  10. Fell, D.B., Platt, R.W., Lanes, A., et al., Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. Bjog, 2015. 122(1): p. 17-26.
  11. McMillan, M., Porritt, K., Kralik, D., Costi, L., and Marshall, H., Influenza vaccination during pregnancy: a systematic review of fetal death, spontaneous abortion, and congenital malformation safety outcomes. Vaccine, 2015. 33(18): p. 2108-17.
  12. Regan, A.K., Moore, H.C., 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): p. 1221-7.
  13. 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): p. 1403-1409.
  14. Foo, D.Y.P., Sarna, M., Pereira, G., et al., Early Childhood Health Outcomes Following In Utero Exposure to Influenza Vaccines: A Systematic Review. Pediatrics, 2020. 146(2).
  15. Ludvigsson, J.F., Winell, H., Sandin, S., et al., Maternal Influenza A(H1N1) Immunization During Pregnancy and Risk for Autism Spectrum Disorder in Offspring. Annals of Internal Medicine, 2020.
  16. Steinhoff, M.C., Katz, J., Englund, J.A., et al., Year-round influenza immunisation during pregnancy in Nepal: a phase 4, randomised, placebo-controlled trial. Lancet Infect Dis, 2017. 17(9): p. 981-989.
  17. Madhi, S.A., Cutland, C.L., Kuwanda, L., et al., Influenza vaccination of pregnant women and protection of their infants. N Engl J Med, 2014. 371(10): p. 918-31.
  18. Omer, S., Maternal Immunization. N Engl J Med, 2017. 376(25): p. 2497.
  19. Nunes, M.C., Cutland, C.L., 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): p. 840-7.
  20. Benowitz, I., Esposito, D.B., Gracey, K.D., Shapiro, E.D., and Vázquez, M., Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis, 2010. 51(12): p. 1355-61.
  21. Regan, A.K., Tracey, L.E., Blyth, C.C., Richmond, P.C., and Effler, P.V., A prospective cohort study assessing the reactogenicity of pertussis and influenza vaccines administered during pregnancy. Vaccine, 2016. 34(20): p. 2299-304.
  22. McNeil, M.M., Weintraub, E.S., Duffy, J., et al., Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol, 2016. 137(3): p. 868-78.
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  24. Thompson, M.G., Kwong, J.C., Regan, A.K., 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): p. 1444-1453.
  25. Regan, A.K., Klerk, N., Moore, H.C., 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): p. 3649-56.