Vaccines in pregnancy in the US

What the CDC recommends

Three vaccines are recommended in pregnancy in the United States: Tdap, influenza and RSV. Each has a specific window, and for two of them the window exists to maximise the antibodies that cross the placenta to your baby.

Tdap — 27 to 36 weeks, every pregnancy

The CDC recommends a dose of Tdap during each pregnancy, irrespective of your prior history of receiving Tdap. Optimal timing is between 27 and 36 weeks of gestation, and available data suggest vaccinating earlier in that window maximises passive antibody transfer to the infant. Tdap may be given at any time in pregnancy if needed, but only one dose per pregnancy — if you receive it earlier, it should not be repeated at 27 to 36 weeks.

The point of this is the newborn period. A CDC evaluation found third-trimester Tdap prevented 78% of pertussis cases in infants under two months old, and was 91% effective against hospitalised cases.

If you have never been vaccinated against tetanus at all, the schedule is three tetanus-containing doses at 0, 4 weeks, and 6 to 12 months, with Tdap replacing one dose, preferably between 27 and 36 weeks.

Influenza — any time during flu season

Pregnant and postpartum people are at higher risk of severe illness from influenza because of changes to the immune system, heart and lungs. Use inactivated (IIV) or recombinant (RIV) influenza vaccine, which can be given at any point in pregnancy while flu viruses are circulating.

The CDC adds timing nuance most people never hear. In the first or second trimester, vaccination is preferably given in September or October, and should be avoided in July and August unless later vaccination might not be possible. In the third trimester, vaccination in July and August can be considered, because multiple studies associate it with reduced influenza illness in infants during their first months, before they are old enough to be vaccinated.

The live attenuated nasal spray flu vaccine (LAIV) is contraindicated in pregnancy. If you are offered the nasal spray, decline it and ask for the shot.

RSV — 32 to 36 weeks, seasonal

Maternal RSV vaccination is recommended as a single dose between 32 weeks 0 days and 36 weeks 6 days of gestation, given seasonally — September through January in most of the continental United States. In places with different RSV seasonality, including Alaska, southern Florida, Guam, Puerto Rico, the US-affiliated Pacific Islands and the US Virgin Islands, follow state, local or territorial guidance on timing.

Two details matter and are easy to get wrong:

• Only Pfizer's RSVpreF (Abrysvo) may be given in pregnancy. Arexvy (GSK) and mResvia (Moderna) should not be administered to pregnant patients.
• It is not repeated. If you received a maternal RSV vaccine in any previous pregnancy, the CDC does not currently recommend another dose in later pregnancies. Instead the baby should receive nirsevimab, an RSV monoclonal antibody. Either maternal vaccination or infant nirsevimab is recommended — not both.

This is a meaningful divergence from the UK, where the NHS offers the RSV vaccine from 28 weeks in every pregnancy.

COVID-19: the CDC and ACOG now disagree

This needs saying plainly rather than smoothed over. The CDC's table of general recommendations for vaccinating pregnant women lists COVID-19 as “No guidance/not applicable.” Following a 2025 change, CDC guidance shifted to individual-based or shared clinical decision-making generally, and no recommendation was issued for pregnant people.

The American College of Obstetricians and Gynecologists takes a different position. ACOG strongly recommends COVID-19 vaccination if you are pregnant, breastfeeding, or planning to get pregnant, stating that the vaccine is safe during pregnancy.

So the federal public health agency has no recommendation and the professional body of obstetricians has a strong one. That gap is real, it is recent, and it may affect whether a pharmacy will vaccinate you without a prescription. If you want the vaccine, raise it with your obstetric provider rather than assuming a pharmacy will administer it — access rules vary by state.

Vaccines that are contraindicated or deferred

• Contraindicated: MMR (measles, mumps, rubella), varicella, live attenuated influenza (LAIV), and live oral typhoid (Ty21a). If indicated, vaccinate after pregnancy. Routine pregnancy testing before MMR or varicella vaccination is not recommended.
• Not recommended: HPV vaccine — pregnancy is a precaution, and vaccination should wait.
• Precaution, not contraindication: yellow fever. If travel is unavoidable and exposure risk outweighs vaccination risk, a pregnant traveler should be vaccinated; otherwise a medical waiver can be issued.
• Recommended when indicated: hepatitis B if you are not already vaccinated — pregnancy is not a contraindication. Hepatitis A if you are at risk of infection or of a severe outcome.

Inadvertent vaccination with a live vaccine is not a reason to end a pregnancy. The CDC states this explicitly for varicella: a patient vaccinated inadvertently should be counseled about the theoretical concern, but vaccination is not a reason to terminate.

Cost and access

Under the Affordable Care Act, most plans cover recommended vaccines without cost-sharing when given by an in-network provider. The CDC's shift on COVID-19 complicates that specific vaccine, since coverage mandates are tied to recommendations. Tdap, flu and RSV in pregnancy remain routinely covered. If you are uninsured, ask your obstetric practice, a Federally Qualified Health Center, or your local health department, which often supply maternal vaccines at low or no cost.

Where to get help

The Centers for Disease Control and Prevention is the governing authority for US immunization schedules, and its guidelines for vaccinating pregnant women carry the current windows and contraindications for every vaccine. ACOG's immunization resources give the obstetric professional view, which currently differs on COVID-19. Your obstetric provider is the right person to reconcile the two for your situation.