What is the most recommended vaccination for a pregnant patient in her 20s coming for her first antenatal visit, Tetanus, Diphtheria, and Pertussis (TDAP) vaccine or Influenza vaccine?

Vaccination Recommendation for First Antenatal Visit

Influenza vaccine is the most appropriate vaccination to administer at this first antenatal visit, as it can be given at any time during pregnancy and during any trimester, whereas Tdap should be deferred until 27-36 weeks' gestation. 1, 2

Rationale for Influenza Vaccination Now

• Pregnant women face 2-3 fold higher rates of ICU admission, invasive ventilation, and mortality from influenza compared to non-pregnant women, making vaccination critical for maternal morbidity and mortality reduction. 2

• The inactivated influenza vaccine (IIV) can be administered at any time during pregnancy, regardless of trimester, providing immediate protection to both mother and fetus. 1

• Annual influenza vaccination is recommended for all women who are or will be pregnant during influenza season (October through May), and should be given as soon as possible during prenatal care. 1, 3, 4

• Maternal vaccination provides passive antibody transfer to the newborn, protecting infants who cannot receive their own influenza vaccine until 6 months of age. 3, 4

Why Tdap Should Be Deferred

• Tdap is NOT recommended at the first antenatal visit unless the patient is already between 27-36 weeks' gestation. 1, 2, 5

• The Advisory Committee on Immunization Practices specifically recommends Tdap administration between 27-36 weeks' gestation during each pregnancy, regardless of prior vaccination history. 1, 2, 5

• Administering Tdap between 27-36 weeks maximizes transplacental antibody transfer to provide optimal passive immunity to the newborn during their most vulnerable period before they can receive DTaP at 2 months of age. 2, 5

• Vaccination as early as possible within the 27-36 week window is recommended to maximize maternal antibody response and passive transfer. 5

Clinical Algorithm for This Patient

1. Administer inactivated influenza vaccine today if the patient has not received it this season, regardless of current gestational age. 1, 2

2. Schedule Tdap vaccination for 27-36 weeks' gestation (preferably at 27 weeks) during a future prenatal visit. 1, 2, 5

3. Document the plan to ensure Tdap is not missed during the optimal window. 5

4. If the patient is already ≥27 weeks' gestation at this first visit, both vaccines can be administered simultaneously using separate syringes at different anatomic sites. 6

Critical Safety Considerations

• Only use inactivated influenza vaccine (IIV) or recombinant influenza vaccine (RIV) in pregnant women—never live attenuated influenza vaccine (LAIV), which is contraindicated due to theoretical risk of placental viral transmission. 1, 2

• Tdap can be safely given at any time during pregnancy if needed for wound management or pertussis outbreaks, but routine administration should follow the 27-36 week guideline for optimal infant protection. 5

• If Tdap is not given during pregnancy, it should be administered immediately postpartum before hospital discharge. 1, 2

Common Pitfall to Avoid

• Do not defer influenza vaccination thinking both vaccines should be given together at 27-36 weeks—this leaves the mother vulnerable to influenza-related complications throughout early and mid-pregnancy when risks are substantial. 1, 3