[1] Tan Tock Seng Hosp, Dept Clin Epidemiol, Off Clin Epidemiol Analyt & Knowledge, 11 Jalan Tan Tock Seng Singapore, Singapore 308433, Singapore
[2] Tan Tock Seng Hosp, Dept Infect Dis, Singapore, Singapore
[3] Tan Tock Seng Hosp, Dept Infect Prevent & Control, Singapore, Singapore
[4] Natl Univ Singapore, Saw Swee Hock Sch Publ Hlth, Singapore, Singapore
[5] Nanyang Technol Univ, Lee Kong Chian Sch Med, Singapore, Singapore