ABSTRACT
Background: The pandemics of coronavirus disease 2019 (COVID-19) threatens both human lives and health care system. COVID-19 patients may differ in their capability in spreading the causative virus, the severe acute respiratory syndrome-corona virus 2 (SARS-CoV-2). Methods: In this study, oropharyngeal swabs specimens from 43 patients admitted to our hospital during the COVID-19 peak time in Wuhan, China were obtained to survey temporal profiles of the viral loads in their upper respiratory tract. An internal and an absolute mRNA control were included in the real-time RT-PCR analysis and RNA extraction step to remove the potential influence of experimental variations on the result interpretation. Results: We found about one third of the hospitalized COVID-19 patients were never tested as SARS-CoV-2 positive during the course of this study. One patient with mild symptoms displayed constant high levels of viral loads after hospitalization, which were orders of magnitude higher than all other positive patients. Conclusions: We propose that if pharyngeal viral loads in a patient could indicate its ability in spreading the virus to others, then identification and strict separation of the high viral load patients should provide an effective mean in restricting viral spreading and protect health care workers from infection.