Temporal Change of SARS-CoV-2 in Clinical Specimens of COVID-19 Pneumonia Patients

Luvira, Viravarn; Jittmittraphap, Akanitt; Muangnoicharoen, Sant; Chantawat, Nantarat; Janwitthayanan, Weena; Leaungwutiwong, Pornsawan

The quality and type of specimen collection affect the sensitivity of real-time reverse transcriptase–PCR (rRT-PCR) for the diagnosis of SARS-CoV-2. In this report, the course over time of rRT-PCR for SARS-CoV-2 in 26 clinical specimens collected from the upper (nasopharyngeal and throat swabs) and lower (sputum) respiratory tracts of COVID-19 cases with pneumonia was investigated along with the clinical course. The preliminary results revealed that higher SARS-CoV-2 RNA concentration and longer time for detection make self-collected sputum a preferable specimen for the diagnosis and follow-up of COVID-19 pneumonia. Self-collection of sputum can minimize the risk of unnecessary exposure to healthcare workers, preserve the shortage of personal protective equipment, and limit viral transmission to the environment.