150 likes | 429 Views
Hepatitis B Virus. Hepatitis B - Clinical Features. Incubation period: Average 60-90 days Range 45-180 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%
E N D
Hepatitis B - Clinical Features • Incubation period: Average 60-90 days • Range 45-180 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 fromchronic liver disease: 15%-25%
Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Symptoms anti-HBe HBeAg Total anti-HBc Titer anti-HBs IgM anti-HBc HBsAg 0 4 8 12 16 24 28 32 52 100 20 36 Weeks after Exposure
Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course Acute (6 months) Chronic (Years) HBeAg anti-HBe HBsAg Total anti-HBc Titer IgM anti-HBc Years 0 4 8 16 20 24 28 36 12 32 52 Weeks after Exposure
Rate of Reported Hepatitis B by Age Group United States, 1990 25 20 15 Rate (per 100,000) 10 5 0 0-14 15-19 20-29 30-39 40+ Age Group (Years) Source: CDC Viral Hepatitis Surveillance Program
Age at Aquisition of Acute and Chronic HBV Infection United States, 1989 Estimates (4% ) Perinatal (24%) (4%) Children (12%) (1-10 yrs) (8%) Adolescent (6%) Adult (59%) Adult (83%) Acute HBV Infections Chronic HBV Infections
Outcome of Hepatitis B Virus Infection by Age at Infection 100 100 80 80 60 60 Chronic Infection Chronic Infection (%) Symptomatic Infection (%) 40 40 20 20 Symptomatic Infection 0 0 1-6 months 7-12 months Older Children and Adults Birth 1-4 years Age at Infection
Global Patterns of Chronic HBV Infection • 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
Geographic Distribution of Chronic HBV Infection HBsAg Prevalence 8% - High 2-7% - Intermediate <2% - Low
Concentration of Hepatitis B Virus in Various Body Fluids Low/Not High Moderate Detectable blood semen urine serum vaginal fluid feces wound exudates saliva sweat tears breastmilk
Hepatitis B Virus Modes of Transmission • Sexual • Parenteral • Perinatal
Risk Factors for Acute Hepatitis B United States, 1992-1993 Heterosexual* (41%) Injecting Drug Use (15%) Homosexual Activity (9%) Household Contact (2%) Health Care Employment (1%) Unknown (31%) Other (1%) * Includes sexual contact with acute cases, carriers, and multiple partners. Source: CDC Sentinel Counties Study of Viral Hepatitis
Elimination of Hepatitis B Virus Transmission United States Objectives • 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 Strategy • Prevent perinatal HBV transmission • Routine vaccination of all infants • Vaccination of children in high-risk groups • Vaccination of adolescents • all unvaccinated children at 11-12 years of age • “high-risk” adolescents at all ages • Vaccination of adults in high-risk groups
Estimated Incidence of Acute Hepatitis B United States, 1978-1995 HBsAg screening of pregnant women recommended 80 Infant immunization recommended Vaccine licensed 70 60 OSHA Rule enacted 50 Cases per 100,000 Population Adolescent immunization recommended 40 30 20 * Decline among homosexual men & HCWs Decline among injecting drug users 10 0 78 79 81 82 83 84 85 87 88 89 90 91 92 93 94 95 80 86 Year * Provisional date