Covid Vaccine While Breastfeeding Protects Baby
Repeated studies reveal Covid antibodies in the breastmilk of people who have been vaccinated
More evidence now shows that people who get the Moderna or Pfizer Covid-19 vaccine while breastfeeding produce protective antibodies against the SARS-CoV-2 virus in their breastmilk, which is then passed along to their baby. While this is not the first study to show Covid antibodies develop in breastmilk after vaccination, it offers yet more proof that getting vaccinated while breastfeeding not only protects yourself but also offers protection to the baby who is nursing.
The study, published in the peer-reviewed journal Breastfeeding Medicine, involved 21 health care workers at the University of Florida’s Shands Hospital who were tracked from December 2020 through March 2021. Seven of them received the Moderna vaccine, and 14 received the Pfizer vaccine. None of the participants had had a previous Covid infection. The researchers collected samples of the women’s blood and breastmilk before they were vaccinated, after their first vaccine dose, and after their second vaccine dose.
The researchers tested the samples for two types of antibodies: IgA and IgG. The first type, IgA, is the type of antibody most often found in breastmilk. It’s also the type found in saliva, tears, sweat, and fluids from your respiratory and digestive systems. IgA antibodies are the body’s first line of defense against a disease at the point where it first enters the body, such as through the nasal passages or mouth.
Meanwhile, IgG antibodies are the most common ones in blood and the ones that tend to do the most heavy-lifting in fighting a specific bacterial or viral infection. Most vaccines typically cause your body to make large amounts of IgG antibodies against a specific pathogen.
The IgA antibodies in the participants’ breastmilk increased after each dose of the vaccine. After they had been completely vaccinated, 85% of the participants’ breastmilk had high levels of IgA in their breastmilk. Past research had found that about 76% to 80% of lactating people with Covid infections had similar levels of IgA antibodies in their breastmilk.
The researchers also tested 10 participants’ breastmilk for IgG antibodies and found high levels of the antibodies in all the breastmilk samples. In fact, the IgG antibody levels in the breastmilk of those vaccinated against Covid were higher than the IgG levels seen in the breastmilk of people who’d had a natural Covid infection.
When the researchers compared antibody levels in the participants’ blood and breastmilk, they found the levels correlated. The higher the levels were in a participant’s blood, the higher they were in the participant’s breastmilk.
Anthony Sciscione, DO, director of maternal-fetal medicine and the OB-GYN residency at Christiana Care in Delaware, said these and previous findings on vaccination during breastfeeding reveal how important and valuable it is for breastfeeding parents to get vaccinated against Covid.
“There’s not going to be a vaccine for newborns any time soon,” Sciscione said. “The best way to protect your baby is the vaccine.”
The study authors noted that previous studies had found even higher levels of IgG antibodies in breastmilk after vaccination. However, it’s still unclear how strong the antibodies that are transferred to babies during nursing are and how long they last.
The IgG antibody levels were a little higher in the breastmilk of those who received the Pfizer vaccine, but the researchers emphasized that that doesn’t necessarily mean those babies had better protection or that the babies whose mothers got Moderna had less protection.
The researchers also did not find any personal characteristics among the participants that made them more or less likely to have higher or lower amounts of antibodies in their breastmilk.
“Interestingly, the participant with the highest concentration of SARS-CoV- 2 IgA in the human milk [12 times higher than the average IgA levels after vaccination among all the participants] was the only participant tandem breastfeeding her two children,” the researchers wrote. They added that past studies have shown higher levels of IgA antibodies the longer a person breastfeeds her child.
None of the studies on Covid vaccination during breastfeeding have found safety concerns related to getting the vaccine while nursing. Past research on other vaccines also has not found safety concerns related to vaccination during lactation. (It’s not even clear what theoretical risks might exist for a baby receiving antibodies through breastmilk.)
The funding for this study came from the Children’s Miracle Network, and the authors had no financial or related ties to pharmaceutical companies.