Sorting through the science on breast milk and COVID-19


Since the Covid-19 pandemic struck, headlines have been full of fluids. There are droplets sprayed when we talk or cough, nasal secretions swabbed for testing, and blood checked for antibodies. But some scientists have focused on a different bodily product: breast milk.

Unlike the others, milk is a fluid made for sharing. That has raised urgent questions about its safety during the crisis, for mothers feeding babies as well as for milk banks handling donations. When an advisory panel for Australian Red Cross Lifeblood, which manages milk banking as well as blood donation, met in March, “there was a lot that was still unknown about Covid-19,” Laura Klein, a research fellow with the organization, wrote via email. “We didn’t know then if the virus could be transmitted through breast milk,” as some other viruses, including HIV and cytomegalovirus, can.

If the virus lurked in breast milk, should infected mothers give their babies formula instead? There were more unknowns. Did milk banks need to take extra precautions with donations? Did breast milk from previously infected women carry antibodies, and could those antibodies protect babies — or maybe other people?

With more than 250 papers on Covid-19 and infant feeding published since February, researchers are beginning to answer these questions, while at the same time contributing to the poorly understood field of breast milk science more generally. They’re discovering that in the time of Covid-19, breast milk is not a fluid to fear.

In the early stages of the pandemic, though, governments were highly cautious when it came to breast milk. In China, where the new coronavirus first emerged, a group of physicians and researchers developed an expert consensus on how to handle infected mothers. Published in February, the document said that infected mothers, and even those with suspected infections, should not