On April 4, Dr. Rebecca Powell posted in her mom Facebook groups: “Are you a healthy, lactating person in NYC? You may be eligible to participate in a breast milk research study!” This wasn’t out of the ordinary for Dr. Powell, a human milk immunologist at The Icahn School of Medicine at Mount Sinai — and a mother of three — who regularly recruits for studies via “mom” social media. This time however, the stakes were higher: She’s examining COVID-19 antibodies in human milk and whether they can protect against the virus.