Naturally immune people will be at little risk of being infected again. Reinfection was counted if a person tested positive at least 90 days after their initial infection. The study was published in the New England Journal of Medicine. After excluding approximately 87,500 people with a vaccination record, researchers found those with immunity from having recovered from Covid-19 had little risk of reinfection and severe cases of the disease. 0.4% of people with natural immunity and without vaccination got Covid-19 a second time. The odds of severe disease were 0.1%. No deaths were reported among those who got infected the second time.