[1] Univ Milan, Dept Hlth Sci, Milan, Italy
[2] ASST Papa Giovanni XXIII, Resp Unit, Bergamo, Italy
[3] San Gerardo Hosp, ASST Monza, Monza, Italy
[4] Univ Milano Bicocca, Dept Med & Surg, Monza, Italy
[5] IRCCS Policlin San Matteo Fdn, Dept Med Sci & Infect Dis, Pavia, Italy
[6] Univ Pavia, Med Sch, Pavia, Italy