An emergency-room doctor tested positive for coronavirus 9 days after getting vaccinated. That's not a sign the vaccine didn't work. Aria Bendix A nurse receiving the Moderna COVID-19 vaccine at Northwell Health's Long Island Jewish Valley Stream hospital on December 21 in Valley Stream, New York. Josh Mugele, an emergency-room doctor in Georgia, tested positive for the novel coronavirus on Tuesday. Mugele received his first dose of Pfizer and BioNTech's coronavirus vaccine nine days earlier. Mugele's COVID-19 infection isn't a sign the shot didn't work. The vaccine requires two shots to be fully effective. It can also take up to a few weeks for vaccinated people to develop immunity, so it's important to continue to wear masks and maintain social distancing after getting the shots.