Pregnant women who get mRNA vaccines pass high levels of antibodies to their babies, according to a study published in American Journal of Obstetrics & Gynecology – Maternal Fetal Medicine on Wednesday.
The study -- one of the first to measure antibody levels in umbilical cord blood to distinguish whether immunity is from infection or vaccines -- found that 36 newborns tested at birth all had antibodies to protect against COVID-19 after their mothers were vaccinated with shots from Pfizer Inc.-BioNTech SE or Moderna Inc.
“We didn’t anticipate that. We expected to see more variability,” said Ashley Roman, an obstetrician at NYU Langone Health System and co-author of the study.
The data could help encourage more women to get vaccinated during their pregnancies. Only 30% of pregnant women ages 18 to 49 are vaccinated, according to Centers for Disease Control and Prevention data from Sept. 11, despite growing evidence of prenatal vaccine safety. Given the study’s small sample size, the team is now looking at results from a larger group, as well as how long immunization lasts for infants after birth.
“We pushed this data out relatively early because it’s a unique finding and it has important implications for care,” Roman said. “Right now we’re recommending all pregnant women receive the vaccine for maternal benefit.”
The National Institutes of Health began a study called MOMI-VAX to measure how long antibodies against Covid-19 will last in people vaccinated during pregnancy. The same researchers will also assess the transfer of vaccine-induced antibodies to infants across the placenta and breast milk.
CDC Meeting
The CDC’s vaccine advisory panel met Wednesday for a general review of vaccine efficacy and safety. They’ve gathered more data on vaccines’ safety during pregnancy from v-safe, a CDC-established registry for people who say they’re pregnant at the time of vaccination, according to Christine Olson, a doctor on the so-called ACIP committee. According to the registry, there’s no evidence vaccines harm the fetus.