The Importance of Vaccination During Pregnancy
The immune system protects the body from things it recognizes as non-self, like viruses and bacteria. However, a fetus can be recognized as non-self too. Therefore, during pregnancy the immune system becomes less reactive so that it does not harm the fetus. Pregnant patients are at high risk for complications of illnesses because their immune system is less reactive.
It also takes time for the immune system of newborns to become stronger, putting them at risk for illnesses early in life. Most vaccines cannot be given to children until they are at least 6 months old.
How Does Vaccination Help?
It is safe to give inactivated vaccines during pregnancy, because people cannot get sick from them.
Vaccination is a safe way for the immune system to learn to recognize specific illnesses without the pregnant person becoming sick. Vaccination during pregnancy allows immunity to be passed from the parent to the infant. This helps protect infants in the first few months of life before they can be vaccinated.
Vaccines are very effective at decreasing the severity of sickness and decreasing the risk of becoming sick if exposed to a given germ. The RSV, flu, COVID-19, and Tdap vaccines are particularly important to receive while pregnant.
Which Vaccines to Avoid in Pregnancy?
It is recommended to avoid most live vaccines during pregnancy. Live vaccines use weakened versions of a virus. Pregnant people’s weaker immune system puts them at risk of becoming sick from these types of vaccines. Live vaccines include chicken pox (Varicella), measles/mumps/rubella (MMR), smallpox/monkeypox (JYNNEOS), cholera oral vaccine (Vaxchora), and typhoid oral vaccine (Vivotif). Pregnant patients should talk to their doctor about the yellow fever vaccine (YF-VAX) if they think they need it.
After receiving a live vaccine, it is recommended to wait at least 4 weeks before trying to conceive.
What are the Risks of Vaccination?
The RSV, flu, COVID-19, and Tdap vaccines can cause a sore arm, redness, or swelling where the vaccine was given. People may experience tiredness, headaches, nausea, and fever that last about 1-3 days. Talk to your doctor if you have a fever.
Serious reactions to vaccines are very rare.
Vaccination Recommendations During Pregnancy
Prepared by Alicia Sasaki, PharmD Candidate 2026
References
- CDC. Vaccine Recommendations Before, During, and After Pregnancy. Pregnancy and Vaccination. Published May 30, 2025. Accessed November 11, 2025. https://www.cdc.gov/vaccines-pregnancy/recommended-vaccines/index.html
- Influenza in Pregnancy Prevention and Treatment. Acog.org. Published 2025. Accessed November 11, 2025. https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2025/08/influenza-in-pregnancy-prevention-and-treatment
- ACOG Releases Updated Maternal Immunization Guidance COVID Influenza RSV. Acog.org. Published 2025. Accessed November 11, 2025. https://www.acog.org/news/news-releases/2025/08/acog-releases-updated-maternal-immunization-guidance-covid-influenza-rsv
- Piekos SN, Price ND, Hood L, Hadlock JJ. The impact of maternal SARS-CoV-2 infection and COVID-19 vaccination on maternal-fetal outcomes. Reprod Toxicol. 2022;114:33-43. The impact of maternal SARS-CoV-2 infection and COVID-19 vaccination on maternal-fetal outcomes – ScienceDirect
- Dugdale C, Santos E, Ciaranello A. Respiratory Syncytial Virus Vaccination in Pregnancy: Safety, Efficacy, and Global Implications. Obstet Gynecol. 2025;145(2):144-146. doi:10.1097/AOG.0000000000005822
- World. Diphtheria. Who.int. Published July 12, 2024. Accessed November 11, 2025. https://www.who.int/news-room/fact-sheets/detail/diphtheria
- Washington sees 25-fold increase in whooping cough cases in 2024 compared to previous year. Washington State Department of Health. Published 2024. Accessed November 26, 2025.
