The Persistence Time of SARS-CoV-2 RNA in Hospitalized COVID-19 Patients: A Prospective Study

In late December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), the causative agent of coronavirus disease 2019 (COVID-19), spread to almost all countries worldwide. The outbreak of this virus has been confirmed on 19th February, 2020, in Iran.

The aim of this study was to investigate the time of viral RNA clearance in swab and serum samples of COVID-19 patients having received different medications. We also evaluated different factors that may affect viral RNA persistence in patients infected by SARS-CoV-2.

In March 2020, twenty-one hospitalized COVID-19 patients participated in this prospective study. All patients received antiviral agents in their routine care. Throat swabs and blood samples were obtained from all patients in different intervals, including day 3 or 5, day 7, day 10, and finally, 14 days after the first positive real-time RT-PCR (rRT-PCT) test.

The median time from the symptom onset (SO) to the first negative rRT-PCR results for throat swabs and serum samples of COVID-19 patients was 18 and 14 days, respectively. These times were more significant in patients with lymphopenia, oxygen saturation ≤ 90%, and comorbidity.

This preliminary study highlights that SASR-CoV-2 RNA was not detectable in the upper respiratory tract for longer than three weeks. In addition, SARS-CoV-2 may persist for a long period of time in the respiratory than in the serum samples. This study supports the idea that in limited resource settings, the patients should be tested earlier than three weeks for discharge management.