This sheet is about exposure to the COVID-19 protein subunit vaccine (Novavax) in pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare provider.
What is COVID-19?
COVID-19 (short for Coronavirus Disease 2019) is an illness caused by the SARS-CoV-2 virus. The virus easily spreads from person to person through respiratory droplets that come from our mouths and noses when we breathe, talk, cough, or sneeze. For more information on COVID-19, please see the MotherToBaby fact sheet at https://mothertobaby.org/fact-sheets/covid-19/.
What is a COVID-19 protein subunit vaccine?
COVID-19 protein subunit vaccines help protect against the virus that causes COVID-19. One protein subunit vaccine is approved for use in the United States, made by Novavax. Protein subunit vaccines do not contain live virus that could cause COVID-19. While no vaccine is 100% effective at preventing COVID-19, the vaccine can greatly reduce the chance of getting very sick from the virus.
For more information on mRNA COVID-19 vaccines, please see the MotherToBaby fact sheet at https://mothertobaby.org/fact-sheets/covid-19-mrna/.
Are COVID-19 protein subunit vaccines recommended for women who are pregnant?
Medical organizations including the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine recommend that women who are planning a pregnancy, pregnant, or recently pregnant, stay up to date with the latest COVID-19 vaccines. The Novavax COVID-19 protein subunit vaccine can be given at any time in pregnancy.
Having a COVID-19 infection while pregnant increases the chance of severe illness and pregnancy complications. Studies have shown that women who are up to date with COVID-19 vaccines in pregnancy are less likely to get very sick or have pregnancy complications from a COVID-19 infection than women who are not up to date.
Can getting a COVID-19 protein subunit vaccine make it harder for me to get pregnant?
COVID-19 protein subunit vaccines have not been studied to see if they can make it harder to get pregnant. However, there is currently no evidence that any vaccines cause fertility problems.
I just got a COVID-19 protein subunit vaccine. How long do I need to wait before I get pregnant?
There is no recommendation to wait before trying to get pregnant after getting a COVID-19 protein subunit vaccine.
Does getting a COVID-19 protein subunit vaccine increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Studies have not been done in humans to see if getting a Novavax COVID-19 protein subunit vaccine during pregnancy would increase the chance of miscarriage.
Does getting a COVID-19 protein subunit vaccine increase the chance of birth defects?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at published data to try to understand if an exposure, like a COVID-19 protein subunit vaccine, might increase the chance of birth defects in a pregnancy. Studies have not been done in humans to see if the Novavax COVID-19 protein subunit vaccine would increase the chance for birth defects. Animal studies in rats did not show an increased chance for birth defects.
Fever is a possible side effect of the COVID-19 protein subunit vaccine. A high fever in the first trimester can increase the chance of certain birth defects. Acetaminophen is usually recommended to reduce fever during pregnancy. For more information about fever and pregnancy, see the MotherToBaby fact sheet about fever/hyperthermia at https://mothertobaby.org/fact-sheets/hyperthermia-pregnancy/.
Does getting a COVID-19 protein subunit vaccine in pregnancy increase the chance of other pregnancy-related problems?
Studies have not been done in humans to see if the Novavax COVID-19 protein subunit vaccine would increase the chance of other pregnancy-related problems, such as preterm delivery (before 37 weeks of pregnancy) or low birth weight (weighing less than 5 pounds, 8 ounces (2500 grams) at birth). Animal studies in rats did not report other pregnancy problems.
Does getting a COVID-19 protein subunit vaccine in pregnancy affect future behavior or learning for the child?
Based on what is known about this and other vaccines, getting a COVID-19 protein subunit vaccine is not expected to cause long-term problems for the child.
Does getting a COVID-19 protein subunit vaccine during pregnancy protect the baby from the virus after delivery?
It is not known if getting a Novavax COVID-19 protein subunit vaccine during pregnancy would protect the baby from COVID-19 after delivery. Studies looking at another type of COVID-19 vaccine (mRNA) show that the antibodies a person makes after getting the vaccine in pregnancy can pass to the developing baby. Research is needed to know if this is also true for protein subunit vaccines.
Breastfeeding and COVID-19 protein subunit vaccines:
Studies have not been done to see if the Novavax COVID-19 protein subunit vaccine passes into breast milk. However, because it is not a live vaccine that can make copies of itself (replicate) and spread through the body, it is not expected to get into the milk.
Organizations including the Academy of Breastfeeding Medicine and the American Academy of Pediatrics agree that people who are breastfeeding can receive COVID-19 vaccines. There is no recommendation to postpone breastfeeding or discard breast milk after getting the Novavax COVID-19 protein subunit vaccine. Talk to your healthcare provider about all of your breastfeeding questions.
If a man gets a COVID-19 protein subunit vaccine, could it affect fertility (ability to get a woman pregnant) or increase the chance of birth defects?
COVID-19 protein subunit vaccines have not been studied to see if they can affect male fertility or increase the chance of birth defects in a partner’s pregnancy. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
If you have received the Moderna or Pfizer vaccine in the last 3 months, you may be a good match for our COVID-19 mRNA vaccine study. Help us help other pregnant people. If you are interested in learning more about this study, please call 1-877-311-8972 or visit: https://mothertobaby.org/join-study/.
Please click here for references.
