Study find traces of coronavirus in breast milk, raises questions on how virus spreads to newborns
Scientists, for the first time, have detected traces of the new coronavirus in the breast milk of an infected mother. But they do not understand whether mothers can pass on the disease to their babies through breastfeeding. They found traces and not the active virus.
"It remains unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be shed into breastmilk and transmitted to a child through breastfeeding," the authors wrote describing their findings in the Lancet Correspondence.
Researchers have a limited understanding of whether Covid-19 spreads through breastmilk. A case study from China has not found the virus in the fluid. And according to the Centers for Disease Control and Prevention (CDC), the limited data available suggest that this mode of spread is unlikely.
Researchers from Germany set out to find some answers. So they included two Covid-19 positive mothers in a German hospital. The team collected the samples in sterile containers and stored them at 4 degrees or -20 degrees to avoid any contamination.
The goal was to check the samples for traces of the new coronavirus. In other words, they looked for parts of the genetic material or RNA of the virus. The first woman's collected samples had no traces of the virus when tested on the 12th, 13th and 14th days of her hospital admission, the study found.
But samples from the second woman who had mild Covid-19 symptoms returned positive. The team detected traces of the virus on days 10, 12, and 13.
Her baby tested positive too, even after the mother followed all the necessary precautions. This includes wearing masks, proper hand and breast disinfection, strict washing, and sterilization of milk pumps and tubes. The researchers are not sure how the newborn caught the disease. "Whether newborn was infected by breastfeeding or other modes of transmission remains unclear," they wrote in their study.
The findings are anecdotal as the team only found the viral RNA in samples from one woman, the co-author Jan Munch, professor at the Institute of Molecular Virology at Ulm University, Germany, told Newsweek. Munch and team call for additional research on milk samples from lactating women to gain more insights. Understanding this can help experts develop recommendations on whether mothers with Covid-19 should feed, according to the researchers. Further, research suggests that breastmilk is protective: mothers pass on antibodies to the babies through the fluid.
In light of the limited evidence on the risks of breastfeeding, the CDC leaves the decision to mothers and physicians. They, however, recommend using cloth face covering while feeding the child and washing hands before each feeding and sterilizing breast pumps for those using it.
"A mother with confirmed Covid-19 should be counseled to take all possible precautions to avoid spreading the virus to her infant, including hand hygiene and wearing a cloth face covering," the CDC said.
"For symptomatic mothers one could think about collecting milk and testing it for the presence of SARS-CoV-2 before feeding. An alternative could be pasteurization, however, it has not yet been demonstrated that this procedure inactivates the virus," Munch told Newsweek.