Reinfections with SARS-CoV-2, the virus that causes the disease, are on the rise, dashing hopes that vaccination or prior disease confers long-lasting immunity to infection. As more people get reinfected, they may be wondering: Do repeat infections lead to more severe COVID symptoms?

Evidence is still limited, but the available data show that while most reinfected people recover within a few days, “others are having a much rougher time,” says Josh Fessel, a pulmonologist at the National Center for Advancing Translational Sciences, in Bethesda, Md. Evaluating the impacts of reinfection—especially with new viral variants arising that are successively more contagious—is an urgent priority, Fessel and other experts say.