As Covid-19 began spreading in early 2020, one of Linfa Wang’s first ideas was to test the blood of people who’d survived a previous coronavirus outbreak. The virologist, who works out of Duke-NUS Medical School, a collaboration between Duke and the National University of Singapore, has been studying bat-borne viruses for decades. He’d helped show that SARS-CoV-1, which killed almost 800 people in 2003, likely jumped to humans from horseshoe bats. Wang’s new theory was that people who’d recovered from the original SARS might harbor antibodies that could help fight the new one, SARS-CoV-2.