[1] Fudan Univ, Sch Publ & Hlth, Shanghai 200032, Peoples R China
[2] London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, London WC1E 7HT, England
[3] Fudan Univ, NHC Key Lab Hlth Technol Assessment, Shanghai 200032, Peoples R China
[4] London Sch Hyg & Trop Med, Dept Global Hlth & Dev, London WC1E 7HT, England
[5] Univ Washington, Dept Hlth Metr Sci, Seattle, WA 98195 USA