[1] Beijing Ctr Dis Prevent & Control, Beijing 100013, Peoples R China
[2] Chinese Ctr Dis Control & Prevent China CDC, State Key Lab Infect Dis Prevent & Control, Beijing 102206, Peoples R China
[3] Chinese Ctr Dis Control & Prevent China CDC, Natl Ctr AIDS STD Control & Prevent NCAIDS, Beijing 102206, Peoples R China
[4] Collaborat Innovat Ctr Diag & Treatment Infect Di, Hangzhou 310003, Zhejiang, Peoples R China
[5] San Francisco Dept Publ Hlth, San Francisco, CA 94102 USA
[6] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94105 USA