Trends in Tdap and influenza vaccination in pregnancy relative to the coronavirus disease-19 pandemic

Abstract

Background: During the COVID-19 pandemic, there were concerns about health and safety, and there was increased medical misinformation about vaccines.

Objectives: Assess how the COVID-19 pandemic impacted Tetanus, Diphtheria, and Pertussis (Tdap) and influenza vaccine administration in pregnancy.

Study design: This was a retrospective review of Tdap and influenza vaccine administration among pregnant patients delivering at our health system from Mar 2018 to Dec 2022. The Acute COVID period was defined by gestational age and estimated due date. Pre-COVID and Chronic COVID periods comprised surrounding matched months. Vaccination groups were: neither, Tdap only, influenza only, or both. Patient characteristics were compared using X² or ANOVA tests. Multinomial logistic regression evaluated COVID period and vaccination status.

Results: 9867 patients were included, with 3967, 1930, and 3970 patients in the Pre-COVID, Acute COVID and Chronic COVID periods. Maternal age (≥35), race and ethnicity, smoking, and diagnosis of chronic hypertension differed significantly by COVID periods. Vaccination rates significantly differed across Pre-, Acute, and Chronic COVID periods. 18.2 %, 9.9 %, and 15.2 % received neither vaccination, and 42.7 %, 50.0 %, and 35.9 % received both vaccines. The proportion receiving Tdap only increased across COVID periods (33.5 %, 36.6 % and 46.0 %, respectively), while influenza only vaccination declined (5.7 %, 3.5 %, and 2.9 %, respectively). In multinomial logistic regression analyses, rates of Tdap only (aOR 2.35; 1.95-2.84) or both vaccinations (aOR 2.63; 2.19-3.17) were higher in Acute COVID period compared to Pre-COVID. Compared to Pre-COVID, rates of Tdap only vaccination were higher in Chronic COVID (aOR 1.64; 1.44-1.87), and receipt of both vaccinations no longer differed. Influenza only vaccination did not differ between Acute COVID and Pre-COVID but was decreased in Chronic COVID (aOR 0.61; 95 % CI 0.47-0.78).

Conclusions: Tdap vaccination was more robust to pandemic influences than influenza vaccination. However, vaccination rates are suboptimal, and efforts are needed to combat vaccine hesitancy and misinformation.

Keywords: COVID-19; Influenza; Prenatal care; Tdap; Vaccination in pregnancy; Vaccine hesitancy.