South-East Asia is a high-prevalence area for hepatitis B, and the World Health Organization (WHO) estimates that the largest proportion -almost 50 per cent - or about 340 million of new STI infections occurring each year happen in South and South-East Asia, especially among the youth (WHO 2007, p. 3). The regional estimate of HIV prevalence among adults aged 15-49 years old is relatively low, in the range of 0.2-0.4 per cent, but the absolute numbers are significant with about 1.7 million people in 2007 living with HIV/ AIDS in South-East Asia (UNAIDS 2008). Thailand, Cambodia, Viet Nam, Myanmar and Indonesia are among the top six countries in Asia in terms of adult cases per 1,000 of population (ADB 2010, p. 96).