SARS-CoV-2 Reinfection within the first 3 months of COVID-19 Recovery in A Referral Hospital, Tehran, Iran

Abstract

ObjectivesPossibility of reinfection with SARS-CoV-2 changes our view on herd immunity and vaccination, and can impact quarantine policies. We performed follow-up studies on recovered patients to assess possible development of reinfections.MethodDuring a 6-month period, 202 PCR-confirmed recovering COVID-19 patients entered this study. Follow-up RT-PCR tests and symptoms assessment were performed one month after the initial Positive results. patients who tested negative were tested again one and three months later. The Serum IgG and IgM levels were measured in the last follow-up session.ResultsIn the first two follow-up sessions, 82 (out of 202) and 44 patients participated with four and three asymptomatic patients testing positive. In the last session, 32 patients were tested and four were positive, three of them were mildly symptomatic and all of them were positive for IgG.ConclusionA positive RT-PCR in a recovering patient may represent reinfection. While we did not have the resources to prove reinfection by genetic sequencing of the infective viruses, we believe presence of mild symptoms in the three patients who tested positive over 100 days after becoming asymptomatic, can be diagnosed as reinfection. The IgG may have abated the symptoms of the reinfection, without providing complete protection.