COVID-19 vaccination and pregnancy: What’s the latest?

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COVID-19 vaccination is recommended for all reproductive-aged women, regardless of pregnancy status.¹ Yet, national vaccination rates in pregnancy remain woefully low—lower than vaccine coverage rates for other recommended vaccines during pregnancy.^2,3 COVID-19 infection has clearly documented risks for maternal and fetal health, and data continue to accumulate on the maternal and neonatal benefits of COVID-19 vaccination in pregnancy, as well as the safety of vaccination during pregnancy.

Maternal and neonatal benefits of COVID-19 vaccination

Does vaccination in pregnancy result in decreased rates of severe COVID-19 infection? Results from a study from a Louisiana health system comparing maternal outcomes between fully vaccinated (defined as 2 weeks after the final vaccine dose) and unvaccinated or partially vaccinated pregnant women during the delta variant—predominant COVID-19 surge clearly answer this question. Vaccination in pregnancy resulted in a 90% risk reduction in severe or critical COVID-19 infection and a 70% risk reduction in COVID-19 infection of any severity among fully vaccinated women. The study also provides some useful absolute numbers for patient counseling: Although none of the 1,332 vaccinated pregnant women in the study required supplemental oxygen or intensive care unit (ICU) admission, there was 1 maternal death, 5 ICU admissions, and 6 stillbirths among the 8,760 unvaccinated pregnant women.⁴

A larger population-based data set from Scotland and Israel demonstrated similar findings.⁵ Most importantly, the Scotland data, with most patients having had an mRNA-based vaccine, showed that, while 77% of all COVID-19 infections occurred in unvaccinated pregnant women, 91% of all hospital admissions occurred in unvaccinated women, and 98% of all critical care admissions occurred in unvaccinated women. Furthermore, although 13% of all COVID-19 hospitalizations in pregnancy occurred among vaccinated women, only 2% of critical care admissions occurred among vaccinated women. The Israeli experience (which identified nearly 30,000 eligible pregnancies from 1 of 4 state-mandated health funds in the country), demonstrated that the efficacy of the Pfizer/BioNTech vaccine to prevent a SARS-CoV-2 infection of any severity once fully vaccinated is more than 80%.⁶

Breakthrough infections, which were more prevalent during the omicron surge, have caused some patients to question the utility of COVID-19 vaccination. Recent data from South Africa, where the omicron variant was first identified, noted that efficacy of the Pfizer/ BioNTech vaccine to prevent hospitalization with COVID-19 infection during an omicron-predominant period was 70%—versus 93% efficacy in a delta-predominant period.⁷ These data, however, were in the absence of a booster dose, and in vitro studies suggest increased vaccine efficacy with a booster dose.⁸

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