From the Guidelines
The shortest interval for DTaP vaccination in pregnant women is no minimum interval if the woman is due for a tetanus booster or has an incomplete vaccination series, but for routine maternal immunization, a single dose of Tdap is recommended during each pregnancy, optimally between 27-36 weeks gestation, regardless of prior vaccination history. According to the most recent guidelines from the Advisory Committee on Immunization Practices 1, Tdap can be administered regardless of the interval since the most recent tetanus or diphtheria-toxoid containing vaccine. The recommended schedule for unvaccinated adults is to administer the first 2 doses at least 4 weeks apart and the third dose 6 to 12 months after the second. However, for pregnant women, the focus is on administering Tdap during each pregnancy to maximize maternal antibody response and passive antibody transfer to the infant. Key points to consider include:
- Tdap vaccination during pregnancy provides protection to the newborn during the vulnerable period before they can receive their own DTaP vaccinations 1
- The maternal Tdap vaccination is crucial because pertussis (whooping cough) can be life-threatening in young infants
- If a pregnant woman has never received tetanus-containing vaccines, she should start the series as soon as possible, with doses spaced at least 4 weeks apart, and ensure one dose is the Tdap vaccine given during the recommended window.
From the Research
DTaP Vaccination in Pregnant Women
- The optimal timing of gestational tetanus-diphtheria-acellular pertussis (Tdap) vaccination is not well-defined, but studies suggest that vaccination during 28-32 weeks of gestation is associated with higher anti-pertussis toxin (PT) immunoglobulin G (IgG) avidity compared to vaccination during 33-36 weeks of gestation 2.
- Pertussis vaccination 5-12 weeks before delivery is associated with higher anti-PT IgG avidity compared to vaccination within 4 weeks before delivery 2.
- There is no specific evidence on the shortest interval for DTaP vaccination in pregnant women, but the studies suggest that the vaccine can be administered at any time during pregnancy, with the optimal time being at 27-36 weeks' gestation as recommended by the Advisory Committee on Immunizations Practices (ACIP) 3.
- Maternal Tdap vaccination is highly protective against infant pertussis, especially in the first 2 months of life, with a vaccine effectiveness of 91.4% (95% confidence interval [CI], 19.5 to 99.1) during the first 2 months of life and 69.0% (95% CI, 43.6 to 82.9) during the entire first year of life 4.
- The safety of Tdap vaccine in pregnant women has been evaluated in several studies, which have shown that the vaccine is well-tolerated with no serious adverse events likely to be caused by the vaccine 5, 6.
Key Findings
- The optimal time for Tdap vaccination during pregnancy is at 27-36 weeks' gestation 3.
- Pertussis vaccination during 28-32 weeks of gestation is associated with higher anti-PT IgG avidity compared to vaccination during 33-36 weeks of gestation 2.
- Maternal Tdap vaccination is highly protective against infant pertussis, especially in the first 2 months of life 4.
- The vaccine is well-tolerated with no serious adverse events likely to be caused by the vaccine 5, 6.