[1] Minist Hlth, Communicable Dis Div, Singapore, Singapore
[2] Natl Ctr Infect Dis, Singapore, Singapore
[3] Natl Univ Singapore, Saw Swee Hock Sch Publ Hlth, Singapore, Singapore
[4] Natl Univ Singapore, Yong Loo Lin Sch Med, Singapore, Singapore
[5] Duke NUS Med Sch, Programme Emerging Infect Dis, Singapore, Singapore
[6] Singapore Immunol Network, Agcy Sci Technol & Res, Singapore, Singapore
[7] Nanyang Technol Univ, Lee Kong Chian Sch Med, Singapore, Singapore
[8] Tan Tock Seng Hosp, Dept Infect Dis, Singapore, Singapore
[9] Minist Hlth, Communicable Dis Div, Singapore 169852, Singapore