How common is this? Aside from the initial news that this happened I haven't heard much. Any studies looking at a larger scale? Friend of mine got COVID, the h

How common is this? Aside from the initial news that this happened I haven't heard much. Any studies looking at a larger scale? Friend of mine got COVID, the health department told him he could get reinfected and to continue taking percautions. He was sick enough with it that he's taking the threat of reinfection seriously.