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Hepatitis B: Disease and prevention

Hepatitis B: Disease and prevention. 3rd June , 2011. LAYOUT OF PRESENTATION. The virus/ es Epidemiology/Statistics HBV disease complications and Transmission Risk groups Prevention, Vaccination. Hepatitis A and B: overview. Hepatitis A and B are inflammatory diseases of the liver 1

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Hepatitis B: Disease and prevention

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  1. Hepatitis B:Disease and prevention 3rd June, 2011

  2. LAYOUT OF PRESENTATION • The virus/es • Epidemiology/Statistics • HBV disease complications and Transmission • Risk groups • Prevention, Vaccination

  3. Hepatitis A and B: overview Hepatitis A and B are inflammatory diseases of the liver1 Caused by different viruses with different modes of transmission1,2 Both HAV and HBV provoke liver damage1,3 Both diseases have similar signs and symptoms1,3 A chronic carrier state may develop only after hepatitis B2 HAV HBV 1. WHO, Hepatitis A, WHO/CDS/CSR/EDC/2000.7 2. CDC, Hepatitis B, Pink book, 2007 3. WHO, WHO/CS/CSR/LYO/2002.2: Hepatitis B

  4. Epidemiology Despite the differences in their modes of transmission and clinical outcome, the geographical distribution of HAV and HBV are similar

  5. Geographical distribution of hepatitis A, 2005 Anti-hepatitis A virus prevalence High Intermediate Low 1.5 million cases per yr CDC, Travelers’ health: yellow book, 2007

  6. Geographical distribution of hepatitis B Hepatitis B surfaceantigen (HBsAg)prevalence High Intermediate Low Mast, et al. MMWR Recomm Rep 2006; 55 (RR16): 1–25

  7. HBV Statistics in Kenya • Prevalence in General Population – 7-10% • Prevalence in Pregnant Women – 9.3% (2001 KPA study) and HBeAg - 8.8% • HBV Markers of Kenyans by early teens – 70%-90% • Prevalence in Blood Donors 5 – 7% • HBeAg in child bearing age women +ve for HBsAg –8 -23.6% • HBeAg higher in children – 60% Wankya et al EAMJ 1979 Okoth et al 1990 EAMJ Sept. 2006 KPA study

  8. What does Hepatitis B cause? • Acute infection with jaundice • Acute infection, (can last for long) asymptomatic or subclinical • Chronic infection - Chronic Liver Disease - Liver cirrhosis - HCC

  9. Typical serological course:acute hepatitis B Symptoms HBeAg anti-HBe Total anti-HBc Antibody titre IgM anti-HBc anti-HBs HBsAg 0 4 8 12 16 24 28 32 52 100 20 36 Weeks after exposure CDC, Hepatitis B slide set, 2007

  10. Typical serological course:chronic hepatitis B Antibody titre 0 4 8 12 16 24 28 32 52 20 36 Weeks after exposure Acute (6 months) Chronic (years) anti-HBe HBeAg HBsAg Total anti-HBc IgM anti-HBc CDC, Hepatitis B slide set, 2007

  11. Hepatitis B: outcome according to age at infection 100 100 80 80 60 60 Chronic infection Symptomatic infection (%) Chronic 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 CDC, Hepatitis B slide set, 2007

  12. Concentration of hepatitis B virus in body fluids CDC, Hepatitis B slide set, 2007

  13. HBV transmission 100-times more infectious than the human immunodeficiency virus (HIV) Transmitted by exposure to infected body fluids (e.g. blood, semen, vaginal secretions): WHO, WHO/CS/CSR/LYO/2002.2: Hepatitis B

  14. Transmission of HBV in Kenya • Horizontal - Most important than vertical - Intrafamilial spread important, (between siblings and btw spouses) - Intrafamilial more important than school spread - high infection rate in infants & children with highest prevalence reached by age ten (may be due to higher HBeAg rate) (Greenfield1986 & Wankya 1979) (Okoth et al 1983 &1990) (Bowry 1983)

  15. Hepatitis B Perinatal Transmission • If mother positive for HBsAg and HBeAg • 70%-90% of infants infected • 90% of infected infants become chronically infected • If positive for HBsAg only • 5%-20% of infants infected • 90% of infected infants become chronically infected

  16. Perinatal Transmission In Asia the rate of HBeAg is highest at 40% hence high PT PT is present in Kenya but less common than horizontal Sexual transmission exists but no studies yet Parenteral transmission less

  17. Hepatitis B Prevention and Vaccination

  18. Hepatitis A & B Hepatitis A Hepatitis B Isolation of Pathogen 1973 1965 FDA vaccine Licensure 1995 1981 Efficacy 94-100% 80-100%

  19. PREVENTION OF HAV & HBV • NO SPECIFIC ANTIVIRAL TREATMENT AVAILABLE FOR BOTH • Improved Sanitation and Hygiene • Safe Sex • Screening of pregnant mothers • Vaccination for all, newborns, children, travellers

  20. HBV IMMUNIZATION • Two types of HBV immunization: - HBV specific immunoglobulin injection - Short term protection - Cab be used at birth to reduce perinatal transmission in HBsAg + mothers • Active Immunization: - Current HBV vaccines are based on synthetically Recombinant HBsA - Contain sections of HBV protein to stimulate a natural immune response - available locally: Euvax B and Engerix B • ;

  21. Hepatitis B risk groups in general Babies born to infected mothers1 Persons living in countries where hepatitis B is endemic1 Family members and sexual contacts of a person infected with hepatitis B1 Healthcare workers (e.g. surgeons, dentists)1 Institutionalised people (developmentally disabled)2 Public safety workers (e.g. police force, fire service, prison service)3 Travellers1 People who have multiple sex partners and men who have sex with men3 Patients on haemodialysis3 Injecting drug users1 Patients with chronic liver disease4 1. WHO, WHO/CS/CSR/LYO/2002.2: Hepatitis B2. Mast, et al. MMWR Recomm Rep 2006; 55 (RR16): 1–253. CDC, Viral hepatitis B fact sheet, 20074. Oldfield & Keefe, Rev Gastroenterol Disord 2007; 7: 1–21

  22. At-risk groups requiring dual protection against hepatitis A and B Travellers to areas endemic for both hepatitis A and B People at occupational risk Institutionalised individuals Sexually active homosexual men Patients with chronic liver disease Van Damme & Van Herck, Expert Rev Vaccines 2004;3: 249–67

  23. Hepatitis B Vaccination Hepatitis B is the most important Vaccine-preventable communicable disease Vaccine: One of the most widely used vaccine in the world Safe, used for >25 yrs 95% effective in preventing children and adults from developing chronic infection Reports of success in reducing carrier rates in children generally from 8-15% to <1% Effective 70-90% in preventing PT given alone within 12 hrs of birth or with Immunoglobulins Co administration with other vaccines together or separatelyVaccines: targeting 2000, 2nd WSIPD Advances in Vaccinology, (1)2007 CKiire Gutt 1996; 38: S5-S12

  24. Cont…. • Taiwan: seroprevalence decreased from 9.8% in 1984 to 0.7% in 1999 and incidence decreased from 0.7:100,000 in 1981/1986 to 0.36:100,000 in 1990-1994 in children. Chan CY. Et al. Legend of hepatitis B vaccination: Taiwan experience. J. Gastroenterol. Hepatol. 2004; 19;: 121-126.

  25. Hepatitis B vaccination • 1992 WHO recommendation for universal Hep B vaccination in all highly endemic (HBsAg carriage rate>8%)countries by 1995 and all other countries by 1997 • Min age of vaccination - birth (monovalent)Schedules – 0,1, 6-12 months - 0,1,2 months for rapid schedule No need for a booster dose in routine vaccination SAGE Recommendation: - In all regions of the world, Perinatal transmission is responsible for a sizable proportion of CHB infections. Hence all infants should receive the first dose of Hep B vaccine as soon as possible after birth.

  26. Hepatitis A vaccination recommendations World Health Organization:1 consider in areas of intermediate endemicity supplements health education and improved sanitation persons at increased risk of hepatitis A virus infection should also be vaccinated Schedule: First dose: 12–23 months: a booster 6- 12m later 1. WHO, Wkly Epidemiol Rec 2000; 5: 38–44 2. Fiore, et al. MMWR Recomm Rep 2006; 55 (RR07: 1–23

  27. HIB Vaccination • Mass vaccination has dramatically reduced the incidence of Hib infections in children under the age of 5 • Vaccine in now used in routine immunization schedule in more than 100 countries worldwide • Vaccines available in Combination with DPT - Pentavalent, Pentaxim, and with HepB - Titanrix www.paho.org/English/HVP/hvp_hib_text.htm

  28. Schedules • Options: I. Birth, 6 wks, 6m II. Birth, 6wks, 6-9m III. 6wks, 10w, 6-9m IV. 6wks, 10wk, 14wk • For HBsAg mothers use the Birth, 6wk, 6mo schedule (birth dose given within 4-12hrs)

  29. KEPI VACCINATION SCHEDULE • Birth • 6 Wks • 1O Wks • 14 Wks • 9 Months • BCG, OPV • OPV, DPT/Hib/HepB • OPV/DPT/Hib/HepB • OPV/DPT/Hib/HepB • Measles, Yellow Fever Mother & Child Health Booklet MOH 216

  30. Efficacy of Hepatitis B vaccination in Kenya 1988/89 • Maragua study, high risk group • Plasma derived HB vaccine – 90.2% • Recombinant HB vaccine – 99.1% • Difference significant • Presently vaccine in use is Recombinant Okoth et al 1990

  31. HBV vaccination studies in Sub-Sahara Africa • Senegal - 93% - 95% seroconversion, - no effect on age, maternal Ab, pregnancy, • SA, Good seroconversion in babies- 93% • Im administration not sc • Booster doses at 5-10 yrs • Mass hepatitis B Vaccination programmes: Kenya, Gambia, Cameroon CKiireGutt 1996; 38: S5-S12

  32. Hepatitis vaccine and HIV • The serological response to hepatitis B vaccines is lower for HIV-infected children and adults than for uninfected persons of similar age. Serological response rates have varied, but most studies have reported that only 25–50% of HIV-infected children have developed protective antibodies.

  33. GAVIHas helped to increase significantly the number of children who have access to immunization worldwide By 2006: • 126M – Hep B • 20M- Hib • 17m – Yellow fever • 1.2 B single use syringes distributed for safe vaccination http://www.gavialliance.org

  34. SUMMARY • Hepatitis B is a serious disease with serious complications and Chronicity • Its a major contributing factor to HCC • Has a variable prevalence with high endemicity in the developing world • It is effectively preventable by the use of Vaccination

  35. THANK YOU

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