Differentials of SARS-CoV-2 Viral RNA Re-positivity in Discharged COVID-19 Patients.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious RNA coronavirus responsible for the pandemic of the coronavirus disease 2019 (COVID-19). Recent advances in virology, epidemiology, diagnosis, and clinical management of COVID-19 have contributed to the control and prevention of this disease, but re-positivity of SARS-CoV-2 in recovered COVID-19 patients has brought a new challenge for this worldwide anti-viral battle. Reverse transcription polymerase chain reaction (RT-PCR) tests of the SARS-CoV-2 pathogen is widely used in clinical diagnosis, but a positive RT-PCR result may be multifactorial, including false positive, SARS-CoV-2 RNA fragment shedding, reinfection of SARS-CoV-2, or re-activation of COVID-19. Re-infection of SARS-CoV-2 or re-activation of COVID-19 is an indicator of live viral carriers and isolation/treatment is needed, but SARS-CoV-2 RNA fragment shedding is not. SARS-CoV-2 RNA is recently reported to integrate into the host genome, but the far-reaching outcome is currently unclear. Therefore, it is critical for appropriate manipulation and prevention of COVID-19 to distinguish these causal factors of SARS-CoV-2 re-positivity. In this review article, we updated the current knowledge of SARS-CoV-2 re-positivity in discharged COVID-19 patients with a focus on re-infection and re-activation. We proposed a hypothetical flowchart for handling of the SARS-CoV-2 re-positive cases.