Many Babies Have Maternal COVID mRNA-Vaccine Antibodies at 6 Months

By Reuters Staff

February 08, 2022

(Reuters) - At six months of age, babies born to mothers vaccinated against COVID-19 during pregnancy are more likely to have antibodies against the virus in their blood than babies born to unvaccinated mothers who were infected while pregnant, a small study suggests.

Researchers reported in JAMA on 28 six-month-old infants born to women who were vaccinated with two doses of an mRNA vaccine at 20 to 32 weeks' gestation, when transfer of maternal antibodies to the fetus via the placenta is at its highest, and 12 babies of that age whose mothers were infected during that same time frame.

They found detectable levels of immunoglobulin G in 57% of babies born to vaccinated mothers but in only 8% of the babies of infected, unvaccinated mothers.

It is not clear how high antibody levels need to be to protect against infection, and antibodies are not the body's only defense mechanism. But "many interested parties from parents to pediatricians want to know how long maternal antibodies persist in infants after vaccination, and now we can provide some answers," Dr. Andrea Edlow of Massachusetts General Hospital in Boston said in a statement. "We hope these findings will provide further incentive for pregnant people to get vaccinated."

SOURCE: JAMA, online February 7, 2022.