Clinical predictors and timing of cessation of viral RNA shedding in patients with COVID-19

Background: Molecular detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is key in the diagnosis of coronavirus disease 2019 (COVID-19) and has been widely used for followup of cases as a proxy for contagiousness. The persistence of SARS-CoV-2 RNA shedding in the context of clinical features and comorbidities is understudied. Methods: We retrospectively reviewed laboratory-confirmed COVID-19 adult symptomatic cases at Mayo Clinic, eventually achieving cessation of viral RNA shedding (CVS), defined as two consecutive negative SARS-CoV-2 PCR results on nasopharyngeal swabs collected at least 24 h apart. Results: A total of 251 patients were included, median age was 53 years and 59 % female. The most common symptoms at diagnosis were cough, myalgia, dyspnea, fever and chills. Myalgia, cough, anosmia, ageusia and sore throat were common at CVS, but fever and dyspnea were not observed. The median time from symptom onset to CVS was 23 days, and did not differ by symptoms. The weekly cumulative CVS rate was 2, 14, 44, 73, 91 and 95 % at 1–6 weeks from symptom onset, respectively. Cough and fever were associated with a positive PCR test if tested within 2 weeks of symptoms (P < 0.05). Patients with asthma or immunosuppression were less likely to achieve CVS if tested 3 weeks into symptoms (P < 0.04). Conclusions: The cumulative CVS rate at 3 weeks from symptom-onset is 44 % in our entire cohort. The findings of our study highlight the low yield of repeating a SARS-CoV-2 NP PCR test within 21 days of a laboratoryconfirmed COVID-19 diagnosis.