[1] Burnet Inst, Ctr Populat Hlth, Melbourne, Vic, Australia
[2] Monash Univ, Sch Publ Hlth & Prevent Med, Melbourne, Vic 3004, Australia
[3] Alfred Hosp, Dept Infect Dis, Melbourne, Vic, Australia
[4] Univ Melbourne, Dept Med, Melbourne, Vic, Australia