Vaccination in Pregnancy

General Principles

• Inactivated vaccines (killed virus, toxoids, subunit, recombinant, polysaccharide): Generally safe in pregnancy. The theoretical risk is extremely low, and in many cases the benefit clearly outweighs any risk.
• Live-attenuated vaccines: Generally contraindicated in pregnancy because of the theoretical risk that vaccine virus replication causes congenital infection or adverse fetal effects. Inadvertent administration of a live vaccine in early pregnancy has not been shown to cause specific embryopathy and is not an indication for termination of pregnancy, but it should be avoided.
• Background rate of major structural fetal malformations in otherwise uncomplicated pregnancies is 3-5%, which must be kept in mind when attributing any birth defect to a vaccine.
• Pregnancy should be avoided for at least 4 weeks after receiving any live-virus vaccine.

Vaccines Routinely Recommended During Every Pregnancy

1. Tdap (Tetanus, Diphtheria, Acellular Pertussis)

• Recommended during every pregnancy, regardless of prior vaccination status or interval since last Td/Tdap dose.
• Optimal timing: 27-36 weeks' gestation (preferably as early as possible in this window) to maximise maternal antibody response and passive IgG transfer to the infant.
• May be given at any time during pregnancy for wound management, during a pertussis outbreak, or other extenuating circumstances.
• If not given during pregnancy and the woman has never received Tdap, it should be given immediately postpartum.
• Can be co-administered safely with inactivated influenza vaccine.

2. Inactivated Influenza Vaccine (IIV)

• Recommended every influenza season, in any trimester.
• Pregnancy itself increases risk of severe influenza even without underlying conditions.
• Protects both the mother and the infant (<6 months) who cannot yet receive the vaccine.
• Live attenuated influenza vaccine (LAIV) is contraindicated in pregnancy.
• Ideally administered in September or October; vaccination in July or August can be considered for those in the third trimester if vaccine is available.

3. COVID-19 Vaccine

• All pregnant persons in any trimester should stay up to date with COVID-19 vaccination (recommended as of 2025 guidelines).
• Given to protect both the pregnant person and the infant.

4. RSV Vaccine

• Nirsevimab (a long-acting monoclonal antibody) or maternal RSV vaccination during 32-36 weeks' gestation (September through January) to protect the newborn from severe RSV disease.
• Every infant should receive protection against severe RSV disease through one of these two strategies.

Other Inactivated Vaccines - Situation-Dependent

Live Vaccines - Contraindicated in Pregnancy

HPV Vaccine

• Not recommended during pregnancy (limited safety data).
• If the patient becomes pregnant after beginning the series, defer remaining doses until after delivery.
• No evidence of harm if inadvertently given, but the series should be paused.
• Ideally complete before pregnancy; if not, complete postpartum.

Recombinant Zoster Vaccine (RZV)

• Recommended to be deferred until after pregnancy.

Preconception Counselling

• Check rubella and varicella immunity; vaccinate with MMR and varicella (live vaccines) at least 1 month, ideally 3 months before attempting conception.
• Update Tdap, influenza, HepB as needed.
• Avoid starting HPV series if pregnancy is imminent.

Postpartum Vaccination

• MMR and varicella, if susceptible, should be given immediately postpartum (not during breastfeeding as a contraindication - breastfeeding is generally not a contraindication to MMR or varicella, though the vaccine viruses may be shed in breast milk).
• Rubella: breastfeeding is NOT a contraindication to rubella immunisation, nor is immunising children of pregnant women.
• Tdap if not given during pregnancy.

Quick Summary Table

Recent Evidence (2024-2025)