1. Presenter ITODO EWAOCHE
Hepatitis B Vaccines
Presenter ITODO EWAOCHE
UNIVERSITY OF CALABAR

2. Prepared by ITODO EWAOCHE
Hepatitis B Vaccines
Prepared by ITODO EWAOCHE
UNIVERSITY OF CALABAR

3. Hepatitis B Vaccines Available since 1981 Composed of HBsAg
Elicits development of neutralizing antibodies to HBsAg
Confers protection from infection
Plasma-derived and recombinant formulations
Hepatitis B Vaccine - Overview
Hepatitis B vaccines have been commercially available since The vaccines are composed of HBsAg conjugated to (an adjunct of) alum. The vaccine elicits the development of neutralizing antibodies to HBsAg, anti-HBs, and these antibodies confer protection from natural HBV infection. Two types of hepatitis B vaccines are available, plasma-derived and recombinant. Plasma-derived vaccines have been available since 1981, and recombinant since 1986.

4. Who should be vaccinated? Adults at Risk for HBV Infection
Sexual exposure
sex partners of HBsAg-positive persons
sexually active persons not in a long-term, mutually monogamous relationship
persons seeking evaluation or treatment for STDs
men who have sex with men

5. Adults at Risk for HBV Infection
Percutaneous or mucosal exposure to blood
Current or recent IDU
Household contacts of HBsAg+ persons
HCWs and public safety workers at risk for exposure to blood or contaminated body fluids
Persons with end-stage renal disease

6. Adults at Risk for HBV Infection
Other groups
International travelers to regions with high or intermediate HBV endemicity
persons with HIV infection

7. Dose schedules Generally, 3 doses recommended
First Injection - At any given time
Time 0
Second Injection - At least one month after the first dose
4 weeks
Third Injection - Six months after the first dose
6 months

8. Childhood vaccination
All children in areas of high endemicity
In Nigeria vaccine introduced in 2004
Pentavalent with DPT
Schedule 6 weeks, 10 weeks, 14 weeks

9. In high endemicity Birth dose vaccine recommended
Not currently in Nigeria due to combination vaccine

10. Immunogenicity and Efficacy of Hepatitis B Vaccines

11. Immunogenicity of Hepatitis B Vaccine
Protective response to vaccine defined as an anti-HBs titer >10 mIU/ml
Seroconversion rates >95% after three doses of vaccine
Immunogenicity of Hepatitis B Vaccine
The protective effect of hepatitis B vaccine is related to the development of neutralizing antibodies to HBsAg, anti-HBs. A protective response to hepatitis B vaccine is defined as the development of an anti-HBs level >10 mIU, measured by enzyme immunoassay. Seroconversion rates of >95% after three doses of vaccine are typically seen in infants and children, with similar rates among recipients of plasma-derived and recombinant vaccines. Concurrent administration of HBIG at birth does not interfere with the antibody response to the vaccine.

12. Factors Associated with Decreased Immunogenicity of Hepatitis B Vaccine
Major Factors
Older age
Immunosuppressive illnesses (HIV
infection, chronic liver disease,
chronic renal failure, diabetes)
Obesity
Smoking
Minor Factors
Factors Associated with Decreased Immunogenicity of Hepatitis B Vaccine
Factors associated with decreased immunogenicity of hepatitis B vaccine include older age, having an immunosuppressive illness such as HIV infection, chronic liver disease, chronic renal failure, and diabetes, and taking immunosuppressive medication such as chemotheraputic agents and steroids (data for these?). Obesity and smoking have also been found to decrease the immunogenicity of vaccine.
Need refs.

13. Efficacy of Hepatitis B Vaccines
Pre-exposure prophylaxis
Efficacy in preventing HBV infection ~95% if vaccinated before exposure
Post-exposure prophylaxis
Efficacy in preventing perinatal infection ~95% if vaccinated within hours of birth
Efficacy of hepatitis B vaccine similar when given with and without HBIG

14. Long-Term Protection with Hepatitis B Vaccine
Vaccine provides long-term protection
Immunity persists despite loss of anti-HBs
Booster doses of hepatitis B vaccine NOT currently recommended
Long-Term Protection of Hepatitis B Vaccine

15. Mechanism of Long-Term Protection with Hepatitis B Vaccine
Primary vaccination series
Immune memory
Anamnestic antibody response
Rapid rise in anti-HBs
Protection from infection
Exposure
to HBV
Long-Term Protection of Hepatitis B Vaccine

16. Effectiveness of Routine Infant Hepatitis B Immunization Programs

17. Effectiveness of Hepatitis B Vaccination Programs
Routine infant hepatitis B immunization
programs decrease:
Incidence of acute hepatitis B
Prevalence of chronic HBV infection
Incidence of hepatocellular carcinoma

18. Prevaccination Serologic Testing
Not indicated before routine vaccination of infants or children
Recommended for
all persons born in Africa, Asia, the Pacific Islands, and other regions with HBsAg prevalence of 8% or higher
household, sex, and needle-sharing contacts of HBsAg-positive persons
HIV-infected persons
Consider for
Groups with high risk of HBV infection (MSM, IDU, incarcerated persons)

19. Postvaccination Serologic Testing
Not routinely recommended following vaccination of infants, children, adolescents, or most adults
Recommended for
Hemodialysis patients
Immunodeficient persons

20. Management of Nonresponse to Hepatitis B Vaccine
Complete a second series of three doses
Should be given on the usual schedule of 0, 1 and 6 months
Retest 1-2 months after completing the second series

21. Prevention of Perinatal Hepatitis B Virus Infection
Begin vaccination within 12 hours of birth
Hepatitis B vaccine (first dose) and HBIG at different sites
Complete vaccination series at 6 months of age
Test for response after completion of at least 3 doses of the HepB series at 9 through 18 months of age

22. Thanks