Current estimates put the prevalence of hepatitis B virus (HBV) infection in Kenya at 5–8%. We determined
the HBV infection prevalence in the human immunodeficiency virus (HIV)–negative Kenyan adult and adolescent
population based on samples collected from a national survey. We analyzed data from HIV-negative participants
in the 2007 Kenya AIDS Indicator Survey to estimate the HBV infection prevalence. We defined past or present HBV
infection as presence of total hepatitis B core antibody (HBcAb), and chronic HBV infection (CHBI) as presence of
both total HBcAb and hepatitis B surface antigen (HBsAg). We calculated crude and adjusted odds of HBV infection
by demographic characteristics and risk factors using logistic regression analyses. Of 1,091 participants aged 15–64 years,
approximately 31.5% (95% confidence interval [CI] = 28.0–35.3%) had exposure to HBV, corresponding to approximately
6.1 million (CI = 5.4–6.8 million) with past or present HBV infection. The estimated prevalence of CHBI was
2.1% (95% CI = 1.4–3.1%), corresponding to approximately 398,000 (CI = 261,000–602,000) with CHBI. CHBI is a
major public health problem in Kenya, affecting approximately 400,000 persons. Knowing the HBV infection prevalence
at baseline is important for planning and public health policy decision making and for monitoring the impact of
viral hepatitis prevention programs.