Introduction: Many individuals test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA after recovering from the coronavirus disease (COVID-19), but the incidence of reactivation is unknown . We, therefore, estimated the incidence of reactivation among individuals who had recovered from COVID-19 and determined its predictors .

Methods: In this retrospective cohort study, patients with COVID-19 were followed up for at least 14 days after two consecutive negative SARS-CoV-2 polymerase chain reaction test results obtained ≥24 hours apart, and the frequency of SARS-CoV-2 reactivation was assessed .

Results: Of the 109 patients , 29 (27 %) experienced reactivation, and seven (24 %) of these were symptomatic . The mean period for the real-time PCR tests for SARS-CoV-2 from negative to positive results was 17 days . Compared with patients without reactivation, those with reactivation were significantly younger and more likely to have a lymphocyte count of <1500/µL (odds ratio [OR]: 0.34 , 95% confidence interval [CI]: 0.12–0.94) and two or fewer symptoms (OR : 0.20 , 95% CI : 0.07–0.55) during the initial episode . Conclusion: Risk-stratified surveillance should be conducted among patients who have recovered from COVID-19.