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Definitions The Epidemiology of Hepatitis A, B, and C Epidemiology: Jamie Berkes M.D. University of Illinois at Chicago [email protected] Definitions A microscopic particle that can infect the cells of biological organisms. Viruses can replicate themselves only by infecting a host cell. Consist of genetic material contained within a protective protein coat. Hepatotropic viruses: Incidence: The number of new cases of a disease during a given time interval, usually one year. Prevalence: The total number of cases of a disease in the population at a given time. Viral Hepatitis in the US Virus:: The study of the incidence and prevalence of diseases in large populations and the detection of the source and cause of epidemics of infectious disease. The study of the relationships between exposures such as nutrition, biological agents, stress, or chemicals to outcomes such as disease, wellness, and health indicators. Predominantly infect the liver. Hepatitis A, B, C, D, and E. AKA; HAV, HBV, HCV, HDV, and HEV. Incubation period: The time between exposure to an infection and when symptoms and signs first occur. Acute infections Acute liver failure deaths/year Chronic infections Chronic liver disease deaths/year HAV HBV HCV 930K 780K 28K 50 100 Rare 0 1-1.25 million 5,000 2.82.8-4 million 0 8,0008,000-10,000 CDC estimates, 2001. 1 REPORTED CASES OF SELECTED NOTIFIABLE DISEASES PREVENTABLE BY VACCINATION, UNITED STATES, 2001 Hepatitis A Hepatitis B Pertussis Meningococcal disease H. influenzae, invasive Mumps Measles Geographic Distribution of Hepatitis A Virus Infection 10,609 7,843 7,580 2,333 1,597 266 116 Source: NNDSS, CDC Hepatitis A: Clinical Features Transmission: 2 to 6 weeks (average 25 days). Infectivity: 2 to 3 weeks. > 1 week prior to the onset of symptoms. Prevalence: > 40% in U.S. have had previous infection. ~ 100% in developing countries. Accounts for 40% of all cases of acute viral hepatitis. Fecal-oral, unsanitary conditions, contaminated food/water, rarely blood. Incubation: Hepatitis A: Epidemiology Groups at risk: Children/workers in day-care Homosexual men Residents and traveler in underdeveloped countries No risk factor identified for 40%-50% of cases. 2 Hepatitis A: Clinical Course Symptoms: Early: fever, nausea and vomiting, fatigue, diarrhea, anorexia. Late: right-upper abdominal pain, dark urine, and jaundice. Severity/Natural history: Age dependant. Jaundice by age group: <6 yrs <10% 6-14 yrs 40%-50% >14 yrs 70%-80% Recover is the rule: provides life long immunity from future infections. Never causes chronic disease. Rarely may lead to fulminant liver failure (<1:3000). 45 40 Rate per 100,000 Reported Cases of Hepatitis A, United States, 19521952-2002 35 30 25 20 15 10 5 0 52 Prevention, prevention, prevention. No effective treatment exists: Liver transplantation. Immune globulin, (IG): For unvaccinated persons, who have recently been exposed to HAV. Must be given within two weeks of exposure to HAV in order to work. 64 68 72 76 80 84 88 92 96 2002 Source: NNDSS, CDC Hepatitis A: Prevention Supportive care. Fulminant Liver Failure: 60 Year Hepatitis A: Treatment 56 Wash hands after using the bathroom, changing a diaper, or before preparing or eating food. Hepatitis A vaccines: Provide long-term protection against hepatitis A. HighHigh-risk persons (IV drug users, homosexual men, travelers to endemic areas). Chronic liver disease. Transplant recipients. Success rate: >95%. 3 Geographic Distribution of Hepatitis B Virus Infection Hepatitis B: Epidemiology 30% of acute viral hepatitis and 15% of chronic viral hepatitis in the US Globally HBsAg Prevalence United States ≥8% - High 2-7% - Intermediate <2% - Low Modes of Transmission Blood transfusion Unknown Household contact Sexual contact Hemodialysis Hepatitis B Occupational exposure Injection drug use Mother-toinfant 350 million persons infected 75% in Asia >500,000 deaths per year 1.25 million persons infected (0.3%) 5-15% of Asian Americans 4-5,000 deaths per year 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 from chronic liver disease: 15%-25% 4 Clinical Features & Natural History 95% clear infection and develop lifelong immunity (HBsAg negative, IgG HBc Ab positive). 5% HBsAg positive for > 6 month = chronic infection Hepatitis B Prevention and Vaccination Chronicity: Chronicity: 90% in neonates, 2525-50% of children <6 years old Inactive carrier state (low viral level, normal LFT’ LFT’s and biopsy) Chronic active hepatitis (elevated LFT’ LFT’s, necrosis and inflammation on liver biopsy) Geographic Distribution of Hepatitis C Virus Infection Prevent perinatal HBV transmission Vaccination is routine for infants Ages 11-15 “catch up”, and through age 18 Over 18 – high risk groups: Occupational risk (Health care workers) Hemodyalisis patients All STD clinic clients Multiple sex partners or prior STD Inmates in Correctional settings MSM IDU Household contacts/sex partners of persons with chronic HBV. Post-vaccination testing: 1-2 months after last shot, if establishing response is critical (HCW). Hepatitis C (HCV) Hepatitis C is a hepatotropic viral that causes chronic inflammation of the liver. Parenteral transmission. 20% of persons infected with HCV develop cirrhosis over a 40-50 year period. Acute and chronic infection is typically asymptomatic until overt liver failure develops (AKA the “silent killer”) HCV has replaced alcoholic liver disease as the leading indication for liver transplantation in the US. 5 Prevalence by Risk Factors Sexual contact Blood transfusion prior to 1992 Tattoos, body piercing Intranasal drug use Organ and tissue transplantation Hepatitis C Injection drug use Percent US population Modes of Transmission 60 50 58% 40 30 20 3.5% 10 0.7% 0 Noscomial Occupational exposure IDU Mother-toinfant Non-IDU No drugs Prevalence of HCV NIH Consensus Development Conference Statement. 2002. Percent US population Sexual Transmission 12 Hepatitis C: Clinical Features Incubation: 2 to 22 weeks Symptoms 10 8 6 4 2 75% asymptomatic, jaundice uncommon Fatigue, right upper quadrant abdominal pain most common symptoms Chronic infection occurs in 6060-85% 85% 30% have normal liver enzymes 0 0-1 2 to 9 10 to 49 # Lifetime Sexual Partners > 50 “silent killer” killer” 6 NHANES III (Third National Health and Nutrition Examination Survey) HCV seropositivity: (1.8%) 3.9 million (3.1-4.8) HCV viremia: (0.96%) 2.7 million (2.4-3.0) Highest observed prevalence: (9.8%) black men 40 to 49 years old. Incidence: 28,000 new infections annually Mortality: 8-10,000 deaths annually NHANES III 1988 - 1994 4.5 Anti-HCV positive (%) Age Specific Prevalence 4 3.5 3 2.5 2 1.5 1 0.5 0 6-11 12-19 20-29 30-39 40-49 Alter MJ, et. al. N Engl J Med 1999 Prevalence (%) 6.0 3.4 2.9 3.0 2.0 1.0 2.9 2.4 2.0 1.8 1.6 0.2 0.4 0.7 0.7 0.0 <20 20-29 30-49 >49 Age Group Alter MJ, et. al. N Engl J Med 1999 P e r c e n t A n ti-H C V P o sitiv e 6.1 4.0 70-79 80+ Prevalence of HCV Infection by Age, Ethnicity, and Gender, 198819881994 7.0 Caucasian Mexican Black 60-69 Alter MJ, et. al. N Engl J Med 1999 HCV Prevalence by Age & Ethnicity 5.0 50-59 Age (Years) 10 9 8 7 6 5 4 3 2 1 0 Black females Black males White males White females 6-11 12-19 20-29 30-39 40-49 50-59 60-69 70+ Age in Years Source: NHANES III 7 Estimated Incidence of Acute Hepatitis C United States, 19821982-2000 Natural History of HCV Infection 100 People Surrogate testing of blood donors 85% Resolve (15) Anti-HCV test (1st generation) licensed Chronic (85) 80% 25% Stable (13) 99 20 00 97 98 96 94 95 92 93 91 89 90 87 88 86 84 85 Mortality (4) Leading Indication for Liver Transplant Source: Sentinel Counties Hepatitis C : Clinical Course 50 Progression Depends on Histologic Activity 100 40 Percent Cirrhosis (17) 75% Decline among injection drug users Decline among transfusion recipients 20% Stable (68) Anti-HCV test (2ndgeneration) licensed 82 83 Cases per 100,000 20 18 16 14 12 10 8 6 4 2 0 Time 15% 30 Predictors Age > 40 > 50 g ETOH Male Fatty liver HIV HBV 20 10 0 < 20 30 Cirrhosis (%) Severe Inflammation Moderate Inflammation 50 Mild Inflammation > 50 Time to Cirrhosis (years) 0 Poynard, Lancet 1997;349:825-832 5 10 Years 15 20 Yano, Hepatology 1996;23:1334-1340 8 Hepatitis C: Indications for Testing Transfusion prior to 1992 Hemodialysis Multiple sexual partners Spouses/partners Injection drug use Intranasal cocaine use Hepatitis C : Prevention No vaccine available Screening and testing donors of blood, organs, and tissues RiskRisk-reduction counseling and services Latex condoms if multiple partners Avoid sharing toothbrushes, razors, combs Cover open wounds Infection control practices Blood and body fluid precautions NIH Consensus Statement, 1997 9