by University of California, San Francisco

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The COVID vaccine is safe to administer during pregnancy, reports UC San Francisco in an important finding on the safety of the vaccine in infants—despite widespread fear and misinformation.

The study, published in JAMA Pediatrics, is the first scientific inquiry into whether infants are at increased risk of neurodevelopmental impairments as a result of maternal vaccination.

The landmark study of more than 2,200 infants from across the country found that in utero exposure to the vaccine caused no abnormal delays when the infants were tested at 12 months and again at 18 months.

"This is a very reassuring finding—pregnant women have been facing unanswered questions around COVID vaccinations for several years," said first author Eleni Jaswa, MD, MSc, a reproductive endocrinologist and fertility specialist at UCSF Health, noting the investigation started in April 2020. She is also an assistant professor in the UCSF Department of Obstetrics, Gynecology & Reproductive Sciences.

First meaningful evidence of maternal vaccination safety during pregnancy

Although pregnant women are considered at increased risk of severe illness with COVID-19, some chose not to get the COVID vaccine due to safety concerns around potential risks to their unborn children.

Some 34% of the participants in the study were vaccinated in the first trimester, about 45% in the second trimester, and nearly 21% in the third trimester. They were asked to complete a 30-item questionnaire assessing whether their infants performed expected milestones.

After adjusting for such factors as maternal age, race, ethnicity, education, income and maternal depression, the researchers found no difference in the risk of infant neurodevelopment at either 12 months or 18 months. They noted an increased risk of delay among male infants at 12 months but the difference was not observed at 18 months.

The study is ongoing.

"Understandably, there's been concern about the potential impact of maternal vaccination on offspring," said senior author Heather Huddleston, MD, a UCSF Health reproductive endocrinologist and director of the UCSF Polycystic Ovary Syndrome Clinic (PCOS).

"Despite early safety data as well as recommendations from physicians and health organizations, vaccine hesitancy is still preventing universal use," she said. "To this day, misinformation continues to abound. People are concerned about such issues as brain development and conditions like autism in children. This is the first meaningful evidence into the safety of vaccination from the standpoint of early offspring neurodevelopment."

All from UCSF, the paper's co-authors are Marcelle Cedars, MD; Karla Lindquist, Ph.D.; Somer Bishop, Ph.D.; Young-Shin Kim, MD, MPH, Ph.D.; Amy Kaing, MD; Mary Prahl, MD; Stephanie Gaw, MD, Ph.D.; Jamie Corley, BS; Elena Hoskin, MS; Yoon Jae Cho, MD; and Elizabeth Rogers, MD.

More information: Eleni G. Jaswa et al, In Utero Exposure to Maternal COVID-19 Vaccination and Offspring Neurodevelopment at 12 and 18 Months, JAMA Pediatrics (2024). DOI: 10.1001/jamapediatrics.2023.5743

Journal information: JAMA Pediatrics 

Provided by University of California, San Francisco