Breast Milk Contains Covid Genetic Material But Infected Mothers Won’t Transmit Virus Through Breastfeeding, Study Finds

Topline

Breastfeeding women infected with Covid-19 cannot transmit the virus through breast milk, according to a peer reviewed study published in Pediatric Research Tuesday, validating a small number of more limited studies and supporting recommendations from health organizations advising mothers to continue breastfeeding after infection and vaccination.

Researchers said there was no evidence breastfeeding could transmit Covid.

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Key Facts

A small proportion of recently infected mothers had genetic material from the virus that causes Covid-19 in their breast milk—6% of women with either a positive test or symptomatic illness or 9% with just a positive test—according to researchers from the University of California, who analyzed samples from 110 women.

However, the researchers said there was “no evidence” breast milk contained infectious virus or genetic material indicating viral replication, noting they were unable to culture the virus from the samples and that the genetic material was only “transiently present.”

There was also “no clinical evidence” to suggest infants got infected when breastfed by a mother with Covid-19, said lead author Paul Krogstad, suggesting “breastfeeding is not likely to be a hazard.”

The study is the largest of its kind so far and provides “substantial” support for a number of smaller studies with similar findings, the researchers said, as well as bolstering guidance from health organizations like the Centers for Disease Control and Prevention and World Health Organization, which recommend mothers continue breastfeeding during the pandemic.

Key Background

There are many benefits to breastfeeding but there are rare cases where breast milk can transmit disease. It is a well-documented route of transmission for HIV and human T cell lymphotropic virus—which can cause a type of leukemia and a progressive nervous system condition—and Ebola virus has been detected in samples of breast milk. The WHO says women with Covid-19 can breastfeed if they want to do so, but warns they should take precautions to prevent passing on the infection by other means, including wearing a mask during feeding, washing hands before and after touching the baby and routinely cleaning surfaces they’ve touched.

Tangent

Vaccination coverage among pregnant and breastfeeding people is well below average, fueled by muddled public health messaging that changed as new information came in and rampant misinformation baselessly suggesting the shots can somehow harm mother, child or both (in fact, a Covid infection can have serious, potentially lethal, consequences for both). While some vaccines can transmit infection to breastfed infants—the CDC cites smallpox and yellow fever vaccines, both of which use live viruses—none of the Covid-19 vaccines in widespread use do. Nor do the vaccines themselves appear in breast milk. Antibodies from the mother are passed on in breast milk, providing some degree of protection against the virus.

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Key Facts

Key Background

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