The prevalence of hepatitis B vaccine has decreased slightly from year-to-year and from one province to another depending on different factors (Graph 1). The prevalence was 3.5% (2.40-4.80%) in 2001 and 3.40% (2.50-4.30%) in 2006 and 1.41% in the Kratie province in 2011 (3.45% in Rattanakiri province and 0.33% in Phnom Penh). The seroprevalence survey 2016 will be conducted in early 2017.12-14