The vaccines showed similar reactions in all three groups of women and triggered both antibody and T-cell reactions against the coronavirus, the scientists found. Of particular concern, experts say, is the fact that in both pregnant and non-pregnant women, the shots produced high levels of neutralizing antibodies that can prevent the virus from entering cells.
“Apparently the vaccines worked on these people,” said Akiko Iwasaki, an immunologist at Yale University who was not involved in the research. “These values are expected to be very protective.”
May 13, 2021, 7:22 a.m. ET
The researchers also found neutralizing antibodies in breast milk of vaccinated mothers and in umbilical cord blood taken from infants at delivery. “Vaccinating pregnant and breastfeeding people actually transfers immunity to their newborns and breastfeeding infants,” said Dr. Ai-ris Y. Collier, a physician-scientist in Beth Israel who is the paper’s first author.
The results are “really encouraging,” said Dr. Iwasaki. “There is this added benefit of imparting protective antibodies to the newborn and fetus, which is all the more reason to get vaccinated.”
The scientists also measured women’s immune responses to two worrying variants: B.1.1.7, which was first identified in the UK and B.1.351, which was first identified in South Africa. All three groups of women responded to both variants with antibodies and T cells after vaccination, although their antibody responses to the variants, particularly B.1.351, were weaker than to the original strain of the virus, according to the study.
“These women developed immune responses to the variants, although the asterisk is that the antibody responses were reduced many times over,” said Dr. Dan Barouch, study author and virologist at Beth Israel. (Dr. Barouch and colleagues developed the Johnson & Johnson vaccine, which was not included in this study.)
“Overall, it’s good news,” he added. “And it adds to the data that suggest vaccinating pregnant women has a significant benefit.”