Factors associated with prolonged viral detection in asymptomatic and mildly symptomatic patients with SARS-CoV-2 infection

Introduction: Data on the clinical course and duration of viral RNA detection in patients with mild or asymptomatic coronavirus disease 2019 are limited. Methodology: In this retrospective analysis, clinical characteristics and serial real-time reverse transcriptase-polymerase chain reaction (RT-PCR) results were reviewed in a cohort of 1186 asymptomatic and mildly symptomatic coronavirus disease 2019 patients in South Korea. Factors associated with prolonged duration of RT-PCR positivity for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) were also evaluated. Patients with two consecutive negative RT-PCR tests ≥ 24 hours apart were considered to be in virologic remission and discharged. Results: The average virologic remission period, defined as the number of days from diagnosis to virologic remission, was 22.0 ± 9.7 days; patients with longer than 30 days accounted for 21.2% (251/1186) of the population. Patients who took longer than 30 days to achieve virologic remission had a higher frequency of overall symptoms (p < 0.001) and respiratory symptoms (p < 0.001). In multivariate analysis using Cox-proportional hazard regression, it was confirmed that respiratory symptoms (hazard ratio [HR], 0.7372; 95% confidence interval [CI], 0.6540-0.8311) and gastrointestinal symptoms (HR, 0.8213; 95% CI, 0.6970-0.9679) were independent factors associated with prolonged virologic remission. Age and co-morbidity such as diabetes and hypertension were not associated with the prolonged RT-PCR positivity. Conclusions: A considerable percentage of asymptomatic and mildly symptomatic patients with coronavirus disease 2019 showed prolonged RT-PCR positivity for SARS-CoV-2; which was independently associated with the presence of symptoms, but not with age and co-morbidity.