How will the vaccines affect my baby?

Key facts

  • When you have a vaccine during pregnancy, the antibodies that your immune system produces will cross the placenta to give your baby protection against the disease, too. 

  • Research shows that the risk of pregnancy complications does not increase for women who have been vaccinated during pregnancy.

Last updated on 27 July 2026.

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Overview

Vaccines work by triggering your immune system to produce antibodies that recognise and get rid of certain diseases and infections. When you are pregnant, those antibodies cross the placenta to give your baby protection, too.

How does the vaccine work?

Vaccines work by training your body’s immune system to recognise and get rid of germs that cause serious illness. They contain ‘antigens’ which are tiny fragments of the virus or bacteria that causes the disease they are targeting. When your immune system detects these antigens, it produces antibodies to fight them and get rid of them.

People usually start producing antibodies around 1 or 2 weeks after they have a vaccine. When you’re pregnant it can take a bit longer.

How will the vaccine affect my baby?

When you have a vaccine during pregnancy, the antibodies that your immune system produces will cross the placenta to give your baby protection against the disease, too. The antibodies can also be passed on through your breastmilk.

How are the vaccines for pregnant women different from other vaccines?

In Australia, only ‘inactivated’ vaccines are recommended for women during pregnancy.  

All vaccines contain ‘antigens’ which are fragments of the bacteria or virus that causes the disease the vaccine is targeting. The antigens in the vaccines recommended for pregnant women are ‘inactivated’ meaning that the bacteria or viruses they are made from have been killed before being introduced to the vaccine. Inactivated antigens cannot reproduce themselves or cause disease.

‘Live’ vaccines contain ‘live’ antigens and should not be given to women during pregnancy.

Are there any risks?

All the vaccines recommended in pregnancy are safe for pregnant women and their babies. Research shows that the risk of pregnancy complications does not increase for women who have been vaccinated during pregnancy, and their babies are not at any greater risk of health issues during pregnancy or at birth.

Read more about the diseases you can be vaccinated against during pregnancy

The hepatitis B vaccine recommended for newborn babies is safe. Research shows that the risks of complications such as Sudden Unexpected Death in Infancy (SUDI) are no higher for babies who have had the hepatitis B vaccine than they are in babies who have not been vaccinated.

The influenza vaccine is safe for pregnant women and for their babies. 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 birth defects.1-4 Specifically:

  • There were lower rates of stillbirth among women who had an influenza vaccine in pregnancy compared with those women who did not get an influenza vaccine in pregnancy.1-3
  • 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.1,4
  • There was no difference in the rates of birth defects among women who had an influenza vaccine in pregnancy compared with those women who did not get a influenza vaccine in pregnancy.2

The whooping cough vaccine is safe for pregnant women and for their babies. Research tells us that being vaccinated against whooping cough during pregnancy does not increase the risk of adverse pregnancy outcomes.5 Specifically, a review of many studies5 confirmed that for mothers vaccinated against whooping cough during pregnancy there was:

  • no increase in the risk of preterm birth (birth under 37 weeks of gestation)
  • no increase in the risk of stillbirth or neonatal death (death during the first 28 days of life)
  • no increase in the risk of babies that were small for gestational age
  • no increase in the risk of low birth weight (less than 2.5kg)
  • and no increase in the risk of birth defects.

The RSV vaccine is safe for pregnant women and their babies. Research shows that being vaccinated against RSV during pregnancy does not increase the risk of adverse pregnancy outcomes.6-9 Specifically:

  • There was no significant increase in preterm births in women who had received the RSV vaccine in pregnancy compared with those women who did not get an RSV vaccine in pregnancy.6-9
  • There was no significant difference in the risk of developing gestational hypertension or preeclampsia in women who had received the RSV vaccine in pregnancy compared with those women who did not get the RSV vaccine in pregnancy.8,9
  • There was no difference in the rates of low birth weight and developmental delays for babies born to mothers who had the RSV vaccine in pregnancy compared with those who didn’t.7

The hepatitis B vaccine is safe for newborns.

  • There is no evidence that the dose given at birth affects a mother and baby’s ability to breastfeed.10,11
  • There is no evidence that the birth dose is associated with Sudden Unexpected Death in Infancy (SUDI) or Sudden Infant Death Syndrome (SIDS).12
  • There is no evidence that the birth dose is associated with autism.13
  • The birth dose is not associated with an increased risk of fever.10,11
  • The birth dose is not associated with an increased need for medical investigations into serious infection or sepsis in newborns.10,11

Most babies who have the hepatitis B vaccine at birth have only very mild reactions such as some redness, soreness or swelling at the spot where the needle went in.10 

Could my baby and I catch the disease from the vaccine?

No. There is no risk that either you or your baby could catch the disease from the vaccines recommended for women during pregnancy, or the hepatitis B vaccine recommended for newborns, because they do not contain any live ‘antigens’. (Antigens are fragments of the bacteria or virus that causes the disease the vaccine is targeting, and are the most important ingredient in the vaccine.) Inactivated antigens cannot reproduce themselves or cause disease.  

In Australia, only ‘inactivated’ vaccines are recommended for women during pregnancy. ‘Live’ vaccines contain ‘live’ antigens and should not be given to women during pregnancy.

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


  1. 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. https://doi.org/10.1111/1471-0528.12977 
  2. McMillan M, Porritt K, Kralik D, et al. Influenza vaccination during pregnancy: a systematic review of fetal death, spontaneous abortion, and congenital malformation safety outcomes. Vaccine 2015;33(18):2108-17. https://doi.org/10.1016/j.vaccine.2015.02.068 
  3. 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. Clinical Infectious Diseases 2016;62(10):1221-7. https://doi.org/10.1093/cid/ciw082 
  4. McHugh L, Andrews RM, Lambert SB, 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. https://doi.org/10.1016/j.vaccine.2017.01.075 
  5. McMillan M, Clarke M, Parrella A, et al. Safety of tetanus, diphtheria, and pertussis vaccination during pregnancy: a systematic review. Obstetrics & Gynecology 2017;129(3):560-73. http://dx.doi.org/10.1097/AOG.0000000000001888 
  6. Kampmann B, Madhi SA, Munjal I, et al. Bivalent prefusion F vaccine in pregnancy to prevent RSV illness in infants. New England Journal of Medicine 2023;388:1451-64. https://doi.org/10.1056/NEJMoa2216480 
  7. Simões EAF, Center KJ, Tita ATN, et al. Prefusion F protein-based respiratory syncytial virus immunization in pregnancy. New England Journal of Medicine 2022;386:1615-26. https://doi.org/10.1056/nejmoa2106062 
  8. Michnick AI, MacDonald SC, Cosgrove A, et al. Interim safety of RSVpreF vaccination during pregnancy. JAMA 2026;335(5):456-59. https://doi.org/10.1001/jama.2025.23452
  9. Kitano T, Sado T, Tsuzuki S, et al. Maternal safety outcomes of respiratory syncytial vaccination during pregnancy with a large-scale database. NPJ Vaccines 2026;11:53. https://doi.org/10.1038/s41541-026-01373-4
  10. Lewis E, Shinefield HR, Woodruff BA, et al. Safety of neonatal hepatitis B vaccine administration. Pediatric Infectious Disease Journal 2001;20:1049-54. https://doi.org/10.1097/00006454-200111000-00009 
  11. Eriksen EM, Perlman JA, Miller A, et al. Lack of association between hepatitis B birth immunization and neonatal death: a population-based study from the Vaccine Safety Datalink Project. Pediatric Infectious Disease Journal 2004;23:656-61. https://doi.org/10.1097/01.inf.0000130953.08946.d0 
  12. Institute of Medicine (US) Immunization Safety Review Committee. Immunization Safety Review: Vaccinations and Sudden Unexpected Death in Infancy. Washington, DC: National Academies Press, 2003. Available from: https://www.ncbi.nlm.nih.gov/books/NBK221465/ 
  13. Taylor LE, Swerdfeger AL, Eslick GD. Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies. Vaccine 2014;32(29):3623-9. https://doi.org/10.1016/j.vaccine.2014.04.085