1. Health Intervention and Technology Assessment Program (HITAP), 6th floor, 6th building, Department of Health, Ministry of Public Health, Tiwanon Rd, Taladkhwan, Mueang Nonthaburi, Nonthaburi 11000, Thailand.
2. University of York, Centre for Health Economics, York, England.
3. MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, England.