A small study of breastmilk and mRNA vaccines did not show babies are being harmed

Did a recent study show that women are harming their babies by breastfeeding after getting mRNA COVID-19 vaccines?

That’s what a claim circulating on Instagram and Facebook feeds suggested.

"7 out of 11 women had mRNA in their breast milk," read an image of a tweet shared on Instagram. "This isn’t just a disaster for infants, it’s more proof that mRNA/LNP in the shots hits practically every cell in the body."

The tweet was written by Alex Berenson, a former New York Times reporter who has shared misleading claims about COVID-19 vaccines. It included a retweet from the Twitter account for the medical journal JAMA promoting the Sept. 22 publication of a study that examined the presence of trace amounts of mRNA vaccines in lactating women’s breast milk.

Contrary to Berenson’s assertion, however, the study did not suggest this amounts to disastrous news for infants. It said results suggested breastfeeding post-vaccination is safe and that more research is needed.

The post was flagged as part of Instagram’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Meta, which owns Facebook and Instagram.)

The study, conducted by researchers from New York University’s Long Island School of Medicine, involved the collection of breast milk samples from 11 women who’d received Pfizer/BioNTech or Moderna COVID-19 vaccines within 6 months after childbirth. The participants were asked to collect samples before being vaccinated and for five days after being vaccinated.

"Of 11 lactating individuals enrolled, trace amounts of BNT162b2 and mRNA-1273 COVID-19 mRNA vaccines were detected in seven samples from five different participants at various times up to 45 hours post-vaccination," part of the study’s results read.

This discovery did not raise alarms for the researchers.

"The sporadic presence and trace quantities of COVID-19 vaccine mRNA detected in EBM (evidence-based medicine) suggest that breastfeeding after COVID-19 mRNA vaccination is safe, particularly beyond 48 hours after vaccination," they said.

The researchers did not test the cumulative effects of that exposure to trace mRNA on the infants and wrote that more research is needed. They also wrote that "caution is warranted about breastfeeding children younger than 6 months in the first 48 hours after maternal vaccination until more safety studies are conducted."

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COVID-19 vaccines are not currently recommended for infants younger than 6 months old. But the Centers for Disease Control and Prevention, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine recommend that "everyone should receive the COVID-19 vaccine, including those who are pregnant or breastfeeding."

Dr. Nazeeh Hanna, the study’s lead author and chief of NYU Langone Hospital-Long Island’s neonatology unit told PolitiFact that although much of the data is still lacking, there’s no evidence to suggest that any amount of either vaccine is harmful to infants who are breastfeeding.

Beyond mRNA vaccines, the FDA has authorized or approved COVID-19 vaccines that do not rely on mRNA technology. These include the Janssen/Johnson & Johnson vaccine and the Novavax vaccine.

An Instagram post suggested that a new study from JAMA showed that traces of mRNA COVID-19 vaccines found in breast milk for seven of 11 mothers are harmful for nursing newborns.

A study involving 11 lactating mothers who had been vaccinated found that samples from five of them contained trace amounts of mRNA COVID-19 vaccines up to 48 hours after vaccination. But researchers said the findings suggested vaccination was safe. They said that until further study is done, women should use caution when breastfeeding infants younger than 6 months in the 48 hours after getting vaccinated. 

We rate this claim Mostly False.