by Regenstrief Institute

Credit: Pixabay/CC0 Public Domain

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% 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%). If received more than six months prior to pregnancy, vaccination provided little protection (6%) against COVID. The research is published in the journal Open Forum Infectious Diseases.

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 health care 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, Ph.D., 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.

Significantly, deidentified data contributed to the study by Regenstrief Institute indicated that pregnant persons in Indiana were half as likely to be vaccinated for COVID-19 than pregnant persons in the other states, including California, Colorado, Minnesota, Oregon, Utah, Washington and Wisconsin, from which data was analyzed. Approximately 65% of those in Indiana who were pregnant were unvaccinated, compared to 30 to 45% in the other states.

"COVID-19 vaccination remains essential for pregnant women's health," said study co-author Shaun Grannis, M.D., M.S., vice president for data and analytics at the Regenstrief Institute and professor of family medicine at the Indiana University School of Medicine.

"As a physician and data scientist, I encourage women to discuss with their doctors the benefits of getting vaccinated or revaccinated to stay protected during pregnancy. Our findings aim to spark vital conversations between physicians and pregnant women and those planning a pregnancy about the safety and protection that the COVID vaccine provides.

"We also hope this work will inspire public health leaders and policymakers in Indiana and across the nation to promote vaccination, reaching women, families, and communities. Ultimately, it's crucial for pregnant individuals to remain current with CDC-recommended COVID-19 vaccinations to safeguard their health."

The study was a collaboration among CDC and seven geographically diverse U.S. health care systems and research centers with integrated medical, laboratory and vaccination records—all members of the CDC's VISION Network.

In addition to Regenstrief Institute, which contributed both data and scientific expertise, VISION sites participating in the study were Columbia University, Health Partners, Intermountain Health, Kaiser Permanente Northern California, Kaiser Permanente Northwest and University of Colorado.

More information: Allison Avrich Ciesla et al, Effectiveness of the Original Monovalent and Bivalent COVID-19 Vaccines Against COVID-19–Associated Emergency Department and Urgent Care Encounters in Pregnant Persons Who Were Not Immunocompromised: VISION Network, June 2022–August 2023, Open Forum Infectious Diseases (2024). DOI: 10.1093/ofid/ofae481

Provided by Regenstrief Institute