A large multistate study, conducted by the Centers for Disease Control and Prevention’s (CDC’s) VISION Network, has found that COVID-19 vaccination given during pregnancy offered 52 per cent protection, cutting risk of a COVID-19-associated emergency department or urgent care visit in half. This is especially significant because there is an increased risk of severe COVID-19 during pregnancy requiring hospitalization and potentially causing adverse pregnancy outcomes.

However, if received less than six months prior to pregnancy, vaccination effectiveness declined providing only moderate protection against COVID (28 percent). If received more than six months prior to pregnancy, vaccination provided little protection (6 percent) against COVID.

Similar to findings in previous VISION studies of those who were not pregnant, protection provided by vaccination against COVID for those who were pregnant waned over four to six months. Also, similar to COVID vaccines for individuals who are not pregnant, effectiveness was comparable to that of the flu vaccine.

The study looked at geographically and racially diverse data from electronic medical records captured during routine healthcare delivery. There was no difference in the protection provided by COVID vaccination by age or race in the study population of 7,677 pregnant 18- to 45-year-olds.

The authors of this study note that their findings, derived from real-world data, indicate the protection provided by either monovalent or bivalent COVID vaccination for those who were pregnant or became pregnant was lower as compared with previous studies, likely due to changes in virus subvariant predominance in 2022-23. Other VISION Network studies have had similar findings in non-pregnant populations.

“The VISION Network did this study to examine the effectiveness of the COVID-19 vaccine for individuals who were pregnant, because there have been a lot of questions as to whether pregnant people should be vaccinated or not,” said study co-author Brian Dixon, PhD, MPA. “Our data show that for Covid-19, vaccines are protective of pregnant persons, supporting CDC guidelines that recommend COVID vaccination.” Dr. Dixon is director and a research scientist with the Clem McDonald Center for Biomedical Informatics at Regenstrief Institute and a professor at the Indiana University Indianapolis Richard M. Fairbanks School of Public Health.