Hepatitis B Virus

Hepatitis B - Clinical Features Incubation period:Average days Range days Clinical illness (jaundice):<5 yrs, <10%  5 yrs, 30%-50% Acute case-fatality rate:0.5%-1% Chronic infection:<5 yrs, 30%-90%  5 yrs, 2%-10% Premature mortality from chronic liver disease:15%-25%

Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Weeks after Exposure Titer Symptoms HBeAg anti-HBe Total anti-HBc IgM anti-HBc anti-HBs HBsAg

Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course Weeks after Exposure Titer IgM anti-HBc Total anti-HBc HBsAg Acute (6 months) HBeAg Chronic (Years) anti-HBe Years

Rate of Reported Hepatitis B by Age Group United States, 1990 Rate of Reported Hepatitis B by Age Group United States, 1990 Age Group (Years) Rate (per 100,000) Source: CDC Viral Hepatitis Surveillance Program

Age at Aquisition of Acute and Chronic HBV Infection United States, 1989 Estimates Age at Aquisition of Acute and Chronic HBV Infection United States, 1989 Estimates Acute HBV Infections Chronic HBV Infections (4% ) Perinatal (24%) (4%) Children (12%) (1-10 yrs) (8%) Adolescent (6%) Adult (83%) Adult (59%)

Outcome of Hepatitis B Virus Infection by Age at Infection Outcome of Hepatitis B Virus Infection by Age at Infection Symptomatic Infection Chronic Infection Age at Infection Chronic Infection (%) Symptomatic Infection (%) Birth 1-6 months7-12 months 1-4 years Older Children and Adults

High (  8%): 45% of global population –lifetime risk of infection >60% –early childhood infections common Intermediate (2%-7%): 43% of global population –lifetime risk of infection 20%-60% –infections occur in all age groups Low (<2%): 12% of global population –lifetime risk of infection <20% –most infections occur in adult risk groups Global Patterns of Chronic HBV Infection

Geographic Distribution of Chronic HBV Infection HBsAg Prevalence  8% - High 2-7% - Intermediate <2% - Low

Concentration of Hepatitis B Virus in Various Body Fluids Concentration of Hepatitis B Virus in Various Body Fluids HighModerate Low/Not Detectable bloodsemenurine serumvaginal fluidfeces wound exudatessalivasweat tears breastmilk

Sexual Parenteral Perinatal Hepatitis B Virus Modes of Transmission Hepatitis B Virus Modes of Transmission

Risk Factors for Acute Hepatitis B United States, Risk Factors for Acute Hepatitis B United States, * Includes sexual contact with acute cases, carriers, and multiple partners. Source: CDC Sentinel Counties Study of Viral Hepatitis Heterosexual* (41%) Homosexual Activity (9%) Household Contact (2%) Health Care Employment (1%) Other (1%) Unknown (31%) Injecting Drug Use (15%)

Prevent chronic HBV Infection Prevent chronic liver disease Prevent primary hepatocellular carcinoma Prevent acute symptomatic HBV infection Elimination of Hepatitis B Virus Transmission United States Objectives

Prevent perinatal HBV transmission Routine vaccination of all infants Vaccination of children in high-risk groups Vaccination of adolescents –all unvaccinated children at years of age –“high-risk” adolescents at all ages Vaccination of adults in high-risk groups Elimination of Hepatitis B Virus Transmission United States Strategy

Estimated Incidence of Acute Hepatitis B United States, Estimated Incidence of Acute Hepatitis B United States, Vaccine licensed HBsAg screening of pregnant women recommended Infant immunization recommended OSHA Rule enacted Adolescent immunization recommended * Decline among homosexual men & HCWs Decline among injecting drug users Year Cases per 100,000 Population * Provisional date