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Hepatitis B Virus. Dr R V S N Sarma., M.D.,. HBsAg Prevalence. ³ 8% - High. 2-7% - Intermediate. <2% - Low. Geographic Distribution of Chronic HBV Infection. Global Patterns of Chronic HBV Infection. High (>8%): 45% of global population lifetime risk of infection >60%
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Hepatitis B Virus Dr R V S N Sarma., M.D.,
HBsAg Prevalence ³8% - High 2-7% - Intermediate <2% - Low Geographic Distribution of Chronic HBV 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
Hepatitis B by Year, United States, 1966 - 2000 HBsAg screening of pregnant women recommended Infant Immunization recommended Vaccine licensed OSHA Rule enacted Adolescent Immunization recommended Decline among injecting drug users Decline among MSM & HCWs Source: NNDSS
Hepatitis B – Clinical Features Incubation periodAverage 60-90 days Range 45-180 days Clinical illness <5 yrs, <10%(jaundice)>5 yrs, 30%-50% Acute case-fatality rate0.5%-1% Chronic infection<5 yrs, 30%-90%>5 yrs, 2%-10% Premature mortality fromchronic liver disease15%-25%
Symptoms HBeAg anti-HBe Total anti-HBc Titer IgM anti-HBc anti-HBs HBsAg 0 4 8 12 16 24 28 32 52 100 20 36 Weeks after Exposure Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course
Acute (6 months) Chronic (Years) HBeAg anti-HBe HBsAg Total anti-HBc Titer IgM anti-HBc 0 4 8 16 20 24 28 36 12 32 52 Weeks after Exposure Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course
HBV Modes of Transmission • Sexual • Parenteral • Perinatal
Low / not High Moderate Detectable Blood Semen Urine Serum Vaginal fluid Feces Wound exudates Saliva Sweat Tears Breast milk Concentration of HBV in Various Body Fluids
Risk Factors Associated with Reported Hepatitis B, 1990-2000 *Other: Surgery, dental surgery, acupuncture, tattoo, other percutaneous injury Source: NNDSS/VHSP
Elimination of HBV Transmission Strategy • Prevent perinatal HBV transmission • Routine vaccination of all infants • Vaccination of children in high-risk groups • Vaccination of adolescents • all children up through age 18 • Vaccination of adults in high-risk groups
Hepatitis B Vaccine • Licensed in 1982; currently recombinant • 3 dose series, typical schedule 0, 1-2, 4-6 months - no maximum time between doses (no need to repeat missed doses or restart) • 2 dose series (adult dose) licensed by FDA for 11-15 year olds (Merck) • Protection ~30-50% dose 1; 75% - 2; 96% - 3; lower in older, immunosuppressive illnesses (e.g., HIV, chronic liver diseases, diabetes), obese, smokers
Hepatitis B Vaccine Safety • Administered to over 12 million infants and children in the United States • – side effects rare • Anaphylaxis estimated to occur in 1/600,000 doses given • No scientific data to link hepatitis B vaccine with multiple sclerosis (MS), other autoimmune diseases, autism
Hepatitis B Vaccination ACIP Recommendations • Routine infant • Ages 11-15 “catch up”, and through age 18(VFC eligible) • Over 18 – high risk • Occupational risk (HCWs) • Hemodyalisis patients • All STD clinic clients • Multiple sex partners or prior STD • Inmates in Correctional settings • MSM • IDU • Institution for developmental disability • Pre-vaccination testing – if cost effective • Post-vaccination testing – 1-2 months after last shot, if establishing response critical (HCW)