Robust COVID-19 Vaccine Response Generated in Pregnant Trial Participants

NIAID Now | March 23, 2021

Although pregnant people are at higher risk for severe COVID-19, pregnant volunteers were not included in the initial clinical trials to evaluate the efficacy of vaccines against SARS-CoV-2 infection, which causes COVID-19. To address the gap in knowledge about COVID-19 vaccination during pregnancy, NIAID-supported researchers enrolled 131 individuals of reproductive age, including 84 pregnant, 31 lactating, and 16 nonpregnant individuals in a cohort study to evaluate the immune response generated by the COVID-19 messenger RNA vaccines. Researchers compared the immune responses in individuals who were pregnant and vaccinated with vaccinated non-pregnant participants, and with the immune responses of those who had been naturally infected with COVID-19 while pregnant. Results showed that vaccine-induced antibody responses were equal between pregnant and lactating individuals compared with nonpregnant participants. Antibody levels after vaccination were significantly higher than those induced by natural infection during pregnancy. Vaccine-generated antibodies were also present in all umbilical cord blood and breastmilk samples. Thus, messenger RNA vaccines induced robust immunity in pregnant and lactating individuals, and this immunity was transferred to newborns via the placenta and breastmilk.

Reference: Gray KJ, Bordt EA, Atyeo C, et al. Coronavirus disease 2019 vaccine response in pregnant and lactating women: a cohort study. Am J Obstet Gynecol 2021; 225: 303.e1-17.

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