Factors associated with a prolonged negative conversion of viral RNA in patients with COVID-19

OBJECTIVES: The aim of this study was to identify the factors influencing the delay in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA negative conversion. METHODS: A cohort study was conducted that included patients with coronavirus disease 2019 (COVID-19) admitted to the Tunisian national containment center. Follow-up consisted of a weekly RT-PCR test. Multivariate Cox regression analysis was performed to determine independent predictors associated with negative RNA conversion. RESULTS: Among the 264 patients included, the median duration of viral clearance was 20 days (interquartile range (IQR) 17–32 days). The shortest duration was 9 days and the longest was 58 days. Factors associated with negative conversion of viral RNA were symptoms such as fatigue, fever, and shortness of breath (hazard ratio (HR) 0.600, 95% confidence interval (CI) 0.401–0.897) and face mask use when exposed to COVID-19 cases (HR 2.006, 95% CI 1.247–3.228). The median time to RNA viral conversion was 18 days (IQR 16–21 days) when using masks versus 23 days (IQR 17–36 days) without wearing masks, and 24 days (IQR 18–36 days) for symptomatic patients versus 20 days (IQR 16–30 days) for asymptomatic patients. CONCLUSIONS: The results of this study revealed that during SARS-CoV-2 infection, having symptoms delayed viral clearance, while wearing masks accelerated this conversion. These factors should be taken into consideration for the strategy of isolating infected patients.