1. Division of AIDS and STIs, Department of Disease Control, Ministry of Public Health, 88/21 Tiwanon Rd., Nonthaburi 11000, Thailand
2. Department of Global Public Health, Karolinska Institutet, Widerströmska huset Tomtebodavägen 18 A, Plan 3, 17165 Stockholm, Sweden
3. Division of Epidemiology, Department of Disease Control, Ministry of Public Health, 88/21 Tiwanon Rd., Nonthaburi 11000, Thailand