Temporal trends in Tdap vaccination coverage during pregnancy in the Vaccine Safety Datalink, 2016 through 2023

In the United States (US), the tetanus, diphtheria, pertussis (Tdap) vaccination is recommended during every pregnancy. However, recent US survey data indicate uptake of the vaccine may be declining. We assessed Tdap vaccination coverage during pregnancy at ten health systems participating in the Vaccine Safety Datalink (VSD) to further examine recent trends.

Using a retrospective cohort, we examined Tdap vaccination coverage among pregnant women aged 12-55 years with a live birth of ≥26 weeks' gestation from January 2016 through December 2023; pregnancies were identified using a validated algorithm. We captured all Tdap, influenza and COVID-19 vaccination during the pregnancy using electronic health records linked to immunization registries. Among women with births in each calendar year, we assessed unadjusted Tdap vaccination coverage overall and by age group and race and ethnicity.

Between 102,374 and 112,297 pregnancies were included in coverage estimates each year. In each year, the population was 33-36% non-Hispanic (NH) White and 62-63% of mothers were 25-34 years old. Tdap vaccination coverage was 84.8% among those with births in 2016, peaked at 88.7% among those with births in 2019 and declined steadily to 83.9% among those with births in 2023. Coverage was consistently lower among those aged 12-17 and 18-24 years, compared to mothers aged ≥25 years. In all years, NH Asian mothers had the highest Tdap vaccination coverage and NH Black mothers had the lowest coverage, with differences of 11.5 to 15.8 percentage points between the two groups each year.

Between 2016 and 2023, Tdap vaccines were administered in more than 80 % of pregnancies ending in live births in the VSD. Gains in coverage seen between 2016 and 2019 were offset by declines in later years. Despite the robust overall coverage, we identified consistent differences by age and race and ethnicity, with gaps widening in later years.