Newborns Benefit From COVID-19 Vaccinated Mothers

A limited study conducted by NYU Langone Health found pregnant women who receive an mRNA COVID-19 vaccine during pregnancy passed high levels of antibodies to their babies.

Existing studies analyzed antibodies to the spike protein (anti-S IgG) alone, which may be present after natural infection or vaccination, and do not include antibodies to the nucleocapsid protein (anti-N IgG), which is only present following natural infection. 

Among the 36 samples collected in this new study, all newborns had high anti-S IgG levels. Of those samples, 31 were tested for anti-N IgG and were negative.

The effectiveness of the Pfizer–BioNTech Comirnaty and Moderna SpikeVax COVID-19 vaccines lies in their ability to trigger the production of the right antibodies, blood proteins capable of protecting individuals from infection, said the researchers in a press release issued on September 22, 2021. 

Published in the American Journal of Obstetrics & Gynecology—Maternal-Fetal Medicine, the study of 36 newborns whose mothers received either mRNA COVID-19 vaccine during pregnancy found that 100% of the infants had protective antibodies at birth.

Antibodies can either be produced as part of the natural response to infection or triggered by vaccines.

With that in mind, the research team was able to tell apart antibodies in the neonatal blood created in response to natural infection from those made in response to the vaccines. 

The result is relevant because natural antibody responses against the SARS-CoV-2 betacoronavirus are not sufficiently protective for many people.

The NYU Langone study authors observed the highest levels of antibodies in cord blood of mothers who were fully vaccinated during the second half of their pregnancies. This insight provides evidence of transferred immunity to neonates, which correlates to protection against infection for infants during the first months of life.

“Studies continue to reinforce the importance of vaccines during pregnancy and their power to protect two lives at once by preventing severe illness in both mothers and babies,” commented Ashley S. Roman, M.D., director of the Division of Maternal-Fetal Medicine and the Silverman Professor of Obstetrics and Gynecology in the Department of Obstetrics and Gynecology at NYU Langone Health, and one of the study’s principal investigators. 

“If babies could be born with antibodies, it could protect them in the first several months of their lives, when they are most vulnerable.”

Dr. Roman and colleagues confirm the strong evidence that the mRNA vaccines are safe during pregnancy in a study published August 16, 2021, in the American Journal of Obstetrics & Gynecology—Maternal-Fetal Medicine, titled “COVID-19 Vaccination in Pregnancy: Early Experience from a Single Institution.” 

This study found no increased risks during pregnancy, birth complications, or identifiable risks to the fetus among those who received the vaccine.

”Our findings add to a growing list of important reasons why women should be advised to receive the COVID-19 vaccine during pregnancy for the added benefit of their newborn receiving crucial protection,” added Dr. Lighter.

Additional research is needed to determine how effective the infant antibodies are, how long protection will last, and if vaccination in the second half of pregnancy may confer higher levels of antibody transfer than vaccination earlier in pregnancy. 

Future studies should also focus on antibody transmission to newborns in a larger population and the durability of antibody detection during infancy.

Disclosures: The authors report no conflict of interest and received no funding for this research.

Recent data from the U.S. Centers for Disease Control and Prevention (CDC) suggests that just 23% of pregnant women have been vaccinated, despite growing evidence of prenatal vaccine safety.

The CDC reported on September 20, 2021, (159) pregnant women (vaccination status undisclosed) have died from COVID-19 since January 2020.

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