2 6 Sweden 2 7 2 8 Abstract = 186 words, Main text = 1722 words, Figures =2. Abstract 3 0 Objectives: Comorbidities have significant indications for the disease outcome of COVID-19, 3 1 however which underlying diseases that contribute the most to aggravate the conditions of 3 2 COVID-19 patients is still largely unknown. SARS-CoV-2 viral clearance is a golden standard 3 3 for defining the recovery of COVID-19 infections. To dissect the underlying diseases that 3 4 could impact on viral clearance, we enrolled 106 COVID-19 patients who were hospitalized in 3 5 Methodology: We comprehensively analyzed demographic, clinical and laboratory data, as 3 8 well as patient treatment records. Survival analyses with Kaplan-Meier and Cox regression 3 9 modelling were employed to identify factors influencing the viral clearance negatively. 4 0 Results: We found that increasing age, male gender, and angiotensin-converting enzyme 2 4 1 (ACE2) associated factors (including hypertension, diabetes, and cardiovascular diseases) 4 2 adversely affected the viral clearance. Furthermore, analysis by a random forest survival 4 3 model pointed out hypertension, cortisone treatment, gender, and age as the four most 4 4 important variables. 4 5 Conclusions: We conclude that patients at old age, males, and/or having diseases 4 6 associated with high expression of ACE2 will have worse prognosis during a COVID-19 4 7 infections. 4 8 4 9