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EPIDEMIOLOGY AND WHO POSITION ON VACCINE VIKASH KESHRI MODERATOR : DR. ABHISHEK RAUT

HEPATITIS B. EPIDEMIOLOGY AND WHO POSITION ON VACCINE VIKASH KESHRI MODERATOR : DR. ABHISHEK RAUT. INTRODUCTION PROBLEM STATEMENT EPIDEMIOLOGY PREVENTION AND CONTROL HEPATITIS B VACCINE WHO POSITION ON HEPATITIS B VACCINE. INTRODUTION.

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EPIDEMIOLOGY AND WHO POSITION ON VACCINE VIKASH KESHRI MODERATOR : DR. ABHISHEK RAUT

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  1. HEPATITIS B EPIDEMIOLOGY AND WHO POSITION ON VACCINE VIKASH KESHRI MODERATOR : DR. ABHISHEK RAUT

  2. INTRODUCTION • PROBLEM STATEMENT • EPIDEMIOLOGY • PREVENTION AND CONTROL • HEPATITIS B VACCINE • WHO POSITION ON HEPATITIS B VACCINE

  3. INTRODUTION • Hepatitis b initially called as serum hepatits is an acute systemic illness with major pathology in liver. • Besides 2 billion infected cases world wide approximately 36 millions live with chronic infection. • These chronically infected people are at increased risk of death from cirrhosis of liver or hepatocellular carcinoma.

  4. PROBLEM STATEMENT WORLD: • Hepatitis B is endemic in almost all part of world • 60% of world population live in endemic area • Estimated 2 billion people infected • 360 million live with chronic infection • 600,000 person dies annually as result of consequence of hepatitis B every year • Estimated 25% child dies in later life as a consequence of hepatitis B infection. • Vaccine coverage estimated is 69%

  5. Problem statement cont….. SEAR: • Estimated one third population in the region infected • 80 million carrier • Estimated 200,000 death occur annually • vaccine coverage 41% according to 2008 WHO-UNICEF antigen study INDIA: • fall in intermediate endemicity group • HBsAg prevalence between 2% to 7%. • Estimated 43-45 million cases per year. • 40 million carriers. • 100,000 death annually by disease related to HBV infection. • Of 25 million newborn annually, 1 milion runs lifetime risk of HBV infection

  6. EPIDEMIOLOGY • AGENT FACTOR: Agent : • Hepatitis B virus belongs to hepadenavirdae family. • Complex 42 nm. Double stranded enveloped DNA virus. • Also known as “Dane” particle. • Has affinity for liver and hepatocytes

  7. Reservoir of infection • Human being only reservoir • Infection spread by cases and carrier • Carrier defined as persistence of HBsAg > 6 months Resistance of virus: • quite stable , can survive for days in environmental condition. • Can be destroyed by sodium hypochlorite • Also by autoclaving for 30 to 60 minutes. Period of communicability: • from incubation period upto disappearnce of HBsAg and upto appearance of antibody. • But can be years.

  8. HOST FACTOR AGE: • outcome age independent • For acute Hepatitis B occurs in 1% perinatal, 10% early childhood (1-5 yrs.) and 30% in older children (>5 yrs. Age) • Development of Chronic hepatitis is inversely proportional to age

  9. HIGH RISK GROUPS • Health care workers • High risk sexual behavior • Commercial sex worker • Frequent blood transfusion reciepient • Injectable drug users • Immunocompromised individuals • Infant of HBV carrier

  10. Modes of transmission Infective materials: • Blood and blood products, serous exudates, saliva, seminal and vaginal fluids, etc. Routes of transmission: 1. Percutaneous 2. sexual 3. perinatal 4. Others routes

  11. Percutaneous routes • injectable drug users • Nonsexual contacts between individuals • Contact with intimate objects • Contact of open skin or mucous membrane with infected materials. • Occupational exposure: needlestick injury, surgical procedure, handling infected materials. • Rituals: circumcision, tatooing, nose and ear piercing.

  12. Sexual routes • Sexual contact with infected person • Favourable factors: -Contact with a person during active infection - H/O sexually transmitted disease - promiscuosity - Male homosexuals perinatal route: • important contributor of high prevalence of infection • Mostly around perinatal period.

  13. Acute infection during third trimester increases risk. • In utero transmission very rare • No evidence of transmission via breast feeding Other routes: • Interpersonal contact specially childhood. May be because of skin to skin contact. INCUBATION PERIOD: • Varies from 30 to 180 days • Average 75 days • HBsAg can be detected as early as 30 days and may persist for several months to years.

  14. Clinical features • Insidious onset • Early symptom : malaise, weakness , anorexia • Ranges from mild asymptomatic infection to fulminant hepatitis to hepatocellular carcinoma to death.

  15. EXPOSURE Clinical infection -jaundice -flu like symptom Asymptomatic Or Subclinical infection Acute hepatitis B infection Recovery Or Immunity Fulminant hepatitis Chronic Carrier Minimal liver Disease Chronic Hepatitis Death Primary hepatocellular carcinoma cirrhosis DEATH

  16. PREVENTION AND CONTROL GOALS OF PREVENTION: • to decrease prevalence of chronic carrier and chronic liver disease • prevention of acute hepatitis B infection Strategies: • Hepatitis B vaccination. • Screening of blood, plasma, organ and semen donor. • Universal precautions.

  17. HEPATITIS B VACCINATION • Active immunization • Passive immunization ACTIVE IMMUNIZATION • Two types of vaccine available 1. Plasma derived vaccine 2. Recombinant DNA vaccine PLASMA DERIVED VACCINE: • Based on HBsAg derived from plasma of human carrier. • Formalin inactivated • Intramuscularly administered • Dose = 1 ml. (contains > 20 mcg. HBsAg.) • costlier

  18. Recombinant DNA vaccine • Introduced in 1987 in USA. • Has replaced plasma derived vaccine. • Cost effective and equally effective • Available as monovalent or combined vaccine Active substance: -HBsAg derived from culture of yeast or mammalian cells Adjuvant: - Alum or thiomersal Storage: -2 to 8°c - freezing avoided -vaccine survive for 7 day at 45°C and for 1 month at 37°c

  19. Administration Age : • Ideal first dose at birth ( within 24 hours) • Next 2 or 3 dose according to immunization schedule • Can be given at any age No. Of doses: • 3 or 4 • First at birth , second and third with DPT1 and DPT3. • First at birth, second, third and fourth with DPT and OPV routine • Older child and adults 3 doses at day o, 1 month, 2 month • no need of booster dose.

  20. Dose : - 0.5 ml. for child < 10 years - 1 ml. For adults Route : - intramuscularly Site : - left upper arm for adults - anterolateral thigh for young infants Hepatitis B vaccine in immunocompromised state: - not contraindicated but special attention required

  21. Immunogenicity and Duration of protection • Usually life long immunity • Hepatitis B or even chronic carrier stage rarely occur. • Role of natural booster by sub- clinical infection is yet to be proved Adverse reaction: • infrequent and rare • Myalgia , transient fever , local pain • No serious adverse effect • Very rarely anaphylactic reaction • No relation with G.B. syndrome or multiple myeloma • GACVS recommends excellent safety profile

  22. Contraindications: • H/O allergic reaction to component of vaccine. • Pregnancy and lactation no contraindication. • HIV positive individual and premature babies can be given vaccine CATCH UP STRATEGY: • Vaccinate older children and adults in low and intermediate endemicity area for population immunity • Target age specific cohort and high risk individual • Strategy may be mandatory vaccination at school and college entry and before joining job. • Target strategic point i.e. STD clinics, centre for IDUs. • Continuous surveillance.

  23. PASSIVE IMMUNIZATION • Hepatitis B immunoglobulin used for temporary post-exposure prophylaxis. • Combined active and passive vaccination better in following cases: - Newborn of HBsAg +ve mother specially if baby +ve - Percutaneous exposure -Sexual exposure - After liver transplant in case of recurrent HBV infection • Time : within 6 hours of exposure and maximum upto 48 hours. • Dose: 0.05 to 0.07 ml. / kg. body weight. • Provides short term passive immunity for 3 months.

  24. WHO POSITION • All newborn should receive birth dose of hepatitis B within 24 hours of birth, in all countries irrespective of their immunity status. • Immunization programme must include HBV. • Proper Reporting and monitoring • MCH care needs to be strenghthened • Schedule include : - First birth dose within 24 hours of birth , followed by either -2 dose schedule with 2 nd and 3rd dose with -DPT 1 and DPT3 -Or 3 dose schedule with routine DPT 1 , 2 and 3.

  25. No need of booster dose • Catch up compaign for older age group is important in intermediate and low endemicity area. • Catch up compaign for infants and young children is important in high endemicity area. • Other target group for catch up strategy can be high risk group. • GACVs confirms excellent safety profile. • WHO recommends all countries should develop goal for HBV control according to their epidemiological situation

  26. References • Park k., text book of preventive and social medicine, 20th edition page no. 186 - 189 • Manson’ text book tropical disease • Maxcy- rosaneu- last text book of public health • heahttp://www.who.int/immunization/topics/hepatitis_b/en/index.htmllth • http://www.who.int/immunization/topics/hepatitis_b/en/index.html

  27. thank you

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