Researchers from Massachusetts General Hospital, Brigham and Women’s Hospital and the Ragon Institute of MGH, MIT and Harvard analyzed 131 women who received the Pfizer / BioNTech or Moderna Covid-19 vaccine. Among the participants, 84 were pregnant, 31 were breastfeeding and 16 were not pregnant. The samples were collected between December 17, 2020 and March 2, 2021.
The levels of antibodies induced by the vaccine were equivalent in pregnant and lactating women, compared to non-pregnant women. The antibody levels were “surprisingly higher” than those resulting from coronavirus infection during pregnancy, the team noted.
“These vaccines seem to work incredibly effectively on these women,” said one of the researchers, Galit Alter, professor of medicine at the Ragon Institute.
In addition, the team found that women passed protective antibodies to their newborns, measured in breast milk and the placenta.
“Almost all mothers were receiving a fairly decent level of antibodies for their babies,” said Alter, who added that further research is needed to understand how long these protective antibodies last in newborns.
Participants used the US Disease Control and Prevention Center’s V-safe tool, which allows people who received the Covid-19 vaccine to track their reaction. Alter said they found no evidence of more side effects or more intense side effects in pregnant and lactating women than in the general population.
While the team found similar levels of antibodies in women vaccinated with both vaccines, Alter said he found higher levels of IgA antibodies in pregnant women who received the Modern vaccine. She said that this specific type of antibody can be transferred more efficiently to babies, for a longer period.
“There is some reason to think that having higher levels of IgA immunity may be more protective,” noted Alter. She said additional research on this discovery could help inform policy decisions about which vaccines are used for pregnant populations.
Recent research has also found that mRNA vaccines illegal antibodies in pregnant women that can be transferred to their babies, although this is the largest study on vaccines in pregnant women to date. Pregnant and lactating women were not included in the initial clinical trials of the vaccines.
Without data to help inform pregnant women’s decisions about vaccination against Covid-19, Alter said that researchers and new and pregnant mothers – mainly health professionals – have taken steps to fill the gap.
“MGH and Brigham started talking to health professionals who were eligible for vaccination, who were also pregnant, and they created a study to empower pregnant women with the ability to track their responses, but also to develop data that could essentially help o The whole world addresses vaccination and pregnancy for the first time in this collective way.
“It was really just a force to be reckoned with, both from the OB-GYN / provider perspective, but also from the community,” said Alter. “It was inspiring.”
According to the CDC, pregnant women with Covid-19 are at higher risk of serious illnesses and may be at higher risk of adverse outcomes, such as premature delivery. The CDC says it hopes to study the safety of the vaccine in about 13,000 pregnant women for each of the three vaccines authorized against the coronavirus. The agency will use a specific V-safe pregnancy record, which enrolled some 3,612 pregnant women as of March 22.
“This is an urgent need, because we are not protecting just one person in this vaccine effort, we are protecting two people at the same time,” said Alter.
Keri Enriquez of CNN Health contributed to this report.