COVID-19(9) SARS-CoV-2(6) material(5) patients(5) Contamination(4) evaluate(4) France(4) performed(4) Infection(4) head and neck cancer(3) Follow-up(3) Patient(3) retrospective(3) Symptom(3) multicentre(2) International(2) tracheostomy(2) head(2) respiratory infection(2) university hospital(2) Univariate analysis(2) recommendation(2) Occurrence(2) carried(2) condition(2) surgical(2) death(2) COVID(2) Postoperative complication(2) ENT(2)