Nearly a year and a half into the COVID-19 pandemic, there are still so many unanswered questions. Interview by Lindsay Smith Rogers | June 8, 2021 What do we know, at this point, about who is at risk of long-COVID? How much immunity is enough immunity to COVID and can we measure this? At this point, what do we know for sure about the origin of SARS-CoV-2? In a Q&A, virologist Gigi Gronvall, PhD, from The Center for Health Security talks about what we know, what we don’t know and what research is underway to answer these and more of some of the biggest lingering questions about COVID-19.