[1] Vietnam Natl Univ, Fac Infect Dis, Sch Med, Ho Chi Minh City, Vietnam
[2] Hosp Trop Dis, Viet Anh Dept, Ho Chi Minh City, Vietnam
[3] Univ New South Wales, Sch Populat Hlth, Kensington, NSW, Australia
[4] Univ Oxford, Emerging Infect Grp, Clin Res Unit, Ho Chi Minh City, Vietnam
[5] Univ Med & Pharm, Dept Infect Dis, Ho Chi Minh City, Vietnam
[6] Univ New South Wales, Sch Populat Hlth, Samuels Bldg, F25,Samuel Terry Ave, Kensington, NSW 2033, Australia