Resumen:
BACKGROUND: SARS-CoV-2, the COVID-19 causative agent, has infected millions of people and killed over 1.6 million worldwide. A small percentage of cases persist with prolonged positive RT-PCR on nasopharyngeal swabs. The aim of this study was to determine risk factors for prolonged viral shedding among patient's basal clinical conditions. METHODS: We have evaluated all 513 patients attended in our hospital between March 1 and July 1. We have selected all 18 patients with prolonged viral shedding, and compared them with 36 sex-matched randomly selected controls. Demographic, treatment and clinical data were systematically collected. RESULTS: Global median duration of viral clearance was 25.5 days (n=54; IQR, 22-39.3 days), 48.5 days in cases (IQR 38.7-54.9 days) and 23 days in controls (IQR 20.2-25.7), respectively. There were not observed differences in demographic, symptoms or treatment data between groups. Chronic rhino-sinusitis and atopy were more common in patients with prolonged viral shedding (67%) compared with controls (11% and 25% respectively) (p<0.001 and p=0,003). The use of inhaled corticosteroids was also more frequent in case group (p=0.007). Multivariate analysis indicated that CRS (odds ratio [OR], 18.78; 95% confidence interval [95%CI],3.89 - 90.59; p<0.001) was independently associated with prolonged SARS-CoV-2 RNA shedding in URT samples, after adjusting for initial PCR Ct values. CONCLUSION: We found that chronic rhino-sinusitis and atopy might be ass