mRNA vaccine for the pregnant produces antibodies that are passed on to the child and remain for at least 6 months
As the COVID-19 pandemic enters its third year, efforts to mitigate the risk of infection remain critical, especially for vulnerable populations.
Recently, Andrea Edlow et al. of Massachusetts General Hospital published a study in the journal JAMA entitled "Durability of Anti-Spike Antibodies in Infants After Maternal COVID-19 Vaccination or Natural Infection".
The study showed that vaccination during pregnancy resulted in longer-lasting antibody levels in infants compared to infants born to unvaccinated and SARS-CoV-2-infected mothers.
The study covered individuals who received two doses of mRNA vaccine or were infected at 20 to 32 weeks of gestation, when antibody transfer through the placenta had reached its peak. The team found that protective antibody levels were detectable in infants born to vaccinated mothers at 6 months of age, while mothers who were not vaccinated or had been infected with SARS-CoV-2 had lower titers or antibody levels at delivery and in their infants.
Although it is not clear how high a titer is needed to fully protect an infant from SARS-CoV-2 infection, we do know that levels of anti-spike protective immunoglobulin G (anti-spike IgG) are associated with protection from severe disease," said study corresponding author Andrea Edlow, MD, Ph.D., a maternal-fetal medicine specialist at Massachusetts General Hospital and director of the Edlow Lab at the Vincent Center for Reproductive Biology. The level of anti-spike IgG is associated with protection from severe disease.
Vaccinated mothers and their cord blood at delivery had higher titers, or antibody levels, than those study participants who were infected with SARS-CoV-2. After two months, 98% (48 of 49) of infants born to vaccinated mothers had detectable levels of protective IgG, the most common antibody in the blood. Six months later, researchers examined 28 infants born to vaccinated mothers and found that 57% (16 of 28) still had detectable IgG. By comparison, only 8% (1 of 12) of infants born to vaccinated mothers had detectable IgG.
Studies on the persistence of antibody responses have revealed that vaccination not only protects the mother for a long time, but also that antibodies remain in most newborns for at least 6 months. Many people, from parents to pediatricians, have wondered how long a mother's antibodies last in her infant after vaccination, and now we can provide some answers. We hope that these findings will provide further incentive for pregnant women to get vaccinated, especially with the emergence of worrisome new variants like Omicron.