Primary outcome
The primary outcome was the duration until conversion, which is defined
as the time between the appearance of symptoms or the initial positive
RT-PCR test and the second negative RT-PCR test outcome. From the second
day of hospitalization onwards, all patients underwent daily RT-PCR
testing using nasopharyngeal swabs
until two consecutive negative results were obtained. According to
China’s COVID-19 diagnosis and treatment guideline Trial Version 9,
criteria for ending isolation and discharge involve obtaining two
consecutive tests result with Ct values of ≥35 for ORF, N, and E genes
with an interval of more than 24 hours[12, 18].