The breast milk of women who’ve been vaccinated with mRNA COVID-19 vaccines contains a significant supply of antibodies that may help keep babies safe, a new study says.
Although there are still many questions about how much protection those antibodies offer infants — and how long that protection lasts — researchers say the findings provide another compelling reason for women who are pregnant, plan to become pregnant, or are breastfeeding to get vaccinated.
“When babies are born, they have a relatively immature system. It develops over time. So the major protections that babies receive come from Mom. So if Mom is producing these antibodies that are present in the breast milk, there is the potential for that protection that Mom has to be transferred over to her baby,” Joseph Larkin III, senior author of the study and an associate professor of microbiology and cell science with the University of Florida, told HuffPost. “This is particularly important because babies can’t be vaccinated right now.”
The study, published in the journal Breastfeeding Medicine this week, was conducted last winter when the Pfizer and Moderna mRNA vaccines first became available to health care workers. As such, it was small — limited to just 21 health care workers who were lactating at the time — and did not include the Johnson & Johnson vaccine, though Larkin told HuffPost that research on that vaccine is happening now.
The women’s breast milk was analyzed pre-vaccine, after the first dose, and after the second dose, and, after each shot, the coronavirus antibodies present in the women’s breast milk increased.
Once the women were fully vaccinated, there was roughly a 100-fold increase in their levels of coronavirus antibodies, the new study found. That’s a greater antibody level than tends to occur when women are infected with the SARS-CoV-2 virus itself.
Even for women who cannot or choose not to breastfeed, vaccination has benefits.
Of course, breastfeeding is challenging, and Larkin told HuffPost he did not want his findings to put unnecessary pressure on women who may be struggling or unable to breastfeed. While most moms in the United States now start off breastfeeding, less than 60% still do it at six months, and breastfeeding pressure can harm women’s mental health.
“As a father of five, I do understand — from an outside perspective — some of the challenges that go into breastfeeding, and I respect that. For those moms that are unable to breastfeed, for many reasons, they shouldn’t be disheartened, because just by being vaccinated she is providing a layer of protection for her baby,” he said.
Indeed, studies have suggested that SARS-CoV-2 antibodies can travel through the placenta.
Also, when mothers and other people who spend time with unvaccinated babies get vaccinated themselves, they’re effectively “cocooning” those babies. So it can be an important preventive measure in addition to steps like masking and limiting time in indoor public settings.
The need to vaccinate pregnant women is “urgent.”
Despite the benefits of vaccination for pregnant and breastfeeding women, their vaccination rates remain low. Less than one-quarter of pregnant women in the U.S. have received a dose of a COVID-19 vaccine.
Yet groups like the Centers for Disease Control and Prevention have said it is “more urgent than ever” to vaccinate people who are trying to conceive and people who are pregnant or breastfeeding.
Unvaccinated pregnant women who get COVID-19 are at much greater risk of serious illness, and hospitals around the country are reporting an uptick in pregnant patients. One fetal medicine specialist in hard-hit Alabama told The Daily Beast about the “terrifying” toll the delta variant is taking on unvaccinated pregnant women there and said doctors sometimes had to perform emergency C-sections on intubated patients. At the same time, pediatric coronavirus cases are soaring.
Experts hope the growing research showing the benefits of vaccination for women and their babies will sway women to do roll up their sleeves. Young children still cannot be vaccinated, though they are likely to be eligible for vaccination sometime this fall or winter. But children ages 5 to 11 will likely qualify first, followed by younger kids.
“The idea of trying to protect those that can’t protect themselves is very, very important,” Larkin said.
Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.