[1] Univ Hosp Geneva, Cent Lab Virol, Div Infect Dis, Dept Internal Med, CH-1211 Geneva 14, Switzerland
[2] Univ Hosp Geneva, Clin Thorac Surg, Dept Surg, CH-1211 Geneva, Switzerland
[3] Univ Hosp Geneva, Dept Internal Med, Div Pulm Med, CH-1211 Geneva 14, Switzerland
[4] Univ Lausanne Hosp, Dept Med, Div Pulm Med, Lausanne, Switzerland
[5] Univ Lausanne Hosp, Inst Microbiol, Lausanne, Switzerland
[6] Univ Lausanne Hosp, Dept Pathol, Div Infect Dis, Lausanne, Switzerland
[7] Univ Hosp Bern, Div Pulm Med, CH-3010 Bern, Switzerland