Pregnant Women Show Robust Immune Response to COVID-19 Vaccine
And passage of antibodies through the placenta and breastmilk appears to confer immunity to newborns
MONDAY, April 5, 2021 (HealthDay News) -- Vaccination of pregnant and lactating women can confer robust maternal and neonatal immunity to COVID-19, according to a study published online March 25 in the American Journal of Obstetrics & Gynecology.
Kathryn J. Gray, M.D., Ph.D., from Brigham and Women's Hospital in Boston, and colleagues evaluated the immunogenicity and reactogenicity of COVID-19 mRNA vaccination in pregnant and lactating women compared to nonpregnant controls and natural COVID-19 infection in pregnancy. Analysis included 84 pregnant, 31 lactating, and 16 nonpregnant women; 37 pregnant women four to 12 weeks from natural infection were also included in the analysis. Titers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike and Receptor Binding Domain (RBD) immunoglobulin (Ig)G, IgA, and IgM were measured in serum (131 participants) and breastmilk (31 participants) at baseline, second vaccine dose, two to six weeks after second vaccine, and delivery (10 participants).
The researchers found that vaccine-induced antibody titers were equivalent in pregnant and lactating compared to nonpregnant women. All titers following vaccination were significantly higher than those induced by natural infection during pregnancy. Vaccine-induced antibodies were detected in all umbilical cord blood and breastmilk samples. Compared to maternal serum, neutralizing antibody titers were lower in umbilical cord serum, although this finding did not achieve statistical significance. The second vaccine dose increased SARS-CoV-2-specific IgG detected in maternal blood and breastmilk, but not IgA.
"We now have clear evidence the COVID vaccines can induce immunity that will protect infants," a coauthor said in a statement. "We hope this study will catalyze vaccine developers to recognize the importance of studying pregnant and lactating individuals, and include them in trials."
Several authors disclosed financial ties to the biotechnology industry.