COVID-19(14) Patient(8) Treatment(8) SARS-CoV-2(6) Infection(6) COVID-19 patient(5) severity(5) association(5) age(5) coronavirus(4) Hospital stay(3) COVID 19(3) 95% confidence interval(3) Transmission(3) significant difference(3) Linear regression model(3) COVID(3) functional(3) reached(3) humans(3) prolonged viral shedding(3) COVID-19 patients(3) retrospective cohort study(3) viral shedding(3) Botulinum toxin(3) Multiple(3) outcome(3) subsequent(3) multiple linear regression models(3) Asymptomatic(3)