No link between first trimester COVID-19 vaccination and birth defects

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pregnant covid
Milan Markovic / iStock

Maternal COVID-19 vaccination in the first trimester of pregnancy is not linked to major structural birth defects, according to a study yesterday in JAMA Pediatrics.

The study was based on outcomes seen among women who received one or two mRNA COVID-19 vaccine doses in the first trimester of pregnancy and gave birth from March 5, 2021, to January 25, 2022, at eight US study sites. 

Among 42,156 eligible pregnant women, 7,632 (18.1%) received an mRNA COVID-19 vaccine in the first trimester. Of the 34524 pregnant women without a first-trimester COVID-19 vaccination, 2,045 (5.9%) were vaccinated before pregnancy, 13,494 (39.1%) during the second or third trimester, and 18,985 (55.0%) were unvaccinated.

No rise in birth defects

Major structural birth defects occurred in 113 infants (1.48%) after first-trimester mRNA COVID-19 vaccination, the authors said, and in 488 infants (1.41%) without first-trimester vaccine exposure. The adjusted prevalence ratio was 1.02 (95% confidence interval, 0.78 to 1.33).

Compared with unvaccinated pregnant women, those vaccinated in the first trimester were older (mean age, 32.3 years compared with 30.6 years).

No significant differences between infants vaccinated or unvaccinated in the first trimester were identified.

"In secondary analyses, with major structural birth defect outcomes grouped by organ system, no significant differences between infants vaccinated or unvaccinated in the first trimester were identified," the authors said. 

NIH announces launch of clinical trial for nasal COVID vaccine

News brief

The National Institutes of Health (NIH) yesterday announced the launch of a phase 1 trial of a nasal vaccine against COVID-19, which also marks the first National Institute for Allergy and Infectious Diseases (NIAID) trial conducted as part of the government's Project NextGen—an effort designed to advance the development of next-generation vaccines against the disease.

purple SARS-CoV-2
NIAID/Flickr cc

In an NIH statement, NIAID Director Jeanne Marrazzo, MD, said first-generation COVID vaccines have greatly mitigated the toll of the disease and are still effective for preventing severe illness, hospitalization, and death. She added, however, that they aren't as good at preventing illness and battling milder disease.

"With the continual emergence of new virus variants, there is a critical need to develop next-generation COVID-19 vaccines, including nasal vaccines, that could reduce SARS-CoV-2 infections and transmission," she said.

Robust systemic, mucosal immune response in animals

The investigational vaccine, called MPV/S-2P, uses a murine pneumonia vector (MPV) to deliver a version of the SARS-CoV-2 spike protein. The NIH said MPV has an affinity for epithelial cells that line the respiratory tract and may be useful for delivering the vaccine to body sites where natural coronavirus infection begins. In preclinical nonhuman primate studies, the vaccine prompted a robust systemic immune response as well as mucosal immunity, which plays a greater role in controlling respiratory virus replication.

There is a critical need to develop next-generation COVID-19 vaccines, including nasal vaccines.

Researchers will enroll 60 adults ages 18 to 64 who have received at least three doses of mRNA COVID vaccine, who will be divided into three groups receiving progressively higher doses of the nasal vaccine. They will be followed up for about 1 year as investigators track participants' immune responses in the blood and nose. Study sites are Baylor College of Medicine in Houston; Hope Clinic at Emory University in Decatur, Georgia; and New York University, Long Island. 

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