1. From the Saw Swee Hock School of Public Health (S.H.X.T., A.R.C., D.H., K.B.T.) and the Yong Loo Lin School of Medicine (D.C.L.), National University of Singapore, the Ministry of Health (D.H., B.O., K.B.T.), the National Centre for Infectious Diseases (D.C.L.), Tan Tock Seng Hospital (D.C.L.), the Lee Kong Chian School of Medicine, Nanyang Technological University (D.C.L.), and the Centre of Regulatory Excellence, Duke–National University of Singapore Medical School (K.B.T.) — all in Singapore.