Nancy H. Nielsen, MD, PhD, senior associate dean for health policy, has been answering questions about COVID-19 in a weekly appearance on WBFO since the pandemic began. She explained that symptoms can linger for months and discussed possible re-infection. She noted that a Hong Kong man was hospitalized for COVID-19 in March, then tested negative twice, and then tested positive again five months later. In South Korea, 285 people were studied who had positive tests months after getting the infection originally. “The theory is that these were likely dead viral particles that were being picked up by testing.” Nielsen said it’s remotely possible to get infected again with a related strain of coronavirus, but “you'll probably be protected anyway.”