Hepatitis B InfectionHepatitis B Infection

Rob HeydermanRob Heyderman

EpidemiologyEpidemiology• One third of the world’s population

(2 billion) people have been infected• 5% chronically infected• China and sub-Saharan Africa 10-20%

seroprevelence• Europe and north America 0.2-0.5%• 500,000 deaths

TransmissionTransmission• Congenital• Childhood• Sexual• Blood transfusion• Needles, acupuncture, IVDU etc• Health workers

ProgressionProgression• Immune response to viral antigens

displayed on the hepatocyte surface determines hepatocellular injury

• Non-cytolytic clearance

• Patients with immune defects have mild liver injury but high rates of carriage

ProgressionProgression• Usually asymptomatic

• Children < 1yr – 90% become chronic• Children 1-5 years – 30% become chronic• Children >5 years – 2% become chronic and

adults

• Yearly frequency for clearance 0.1-0.8%

ProgressionProgression

*DNA may be detectable at low

levels

DNA DNA

* ? Infectious

ProgressionProgression

Chronic Carriage Cirrhosis

Liver failure

Hepatoma

20%

X100 risk

fpU/S screening

15-40%

DiagnosisDiagnosis• Hepatitis B surface antigen• HBeAg• HBeAb• PCR

• Liver biopsy

TreatmentTreatment• ALT 1.5X normal• HBV detectable• Interferon = immunomodulation

Lamivudine and adefovir = viral suppression• Liver transplantation• Endpoints (controversial)

– ALT– Loss of HBeAg– ?anti-HBeAb– Undetectable HBV DNA– Histology (?tissue PCR)

PreventionPrevention• General measures

– Universal precautions– Blood screening– Maternal screening

• Hepatitis B vaccination– 3 doses– ? Life-long immunity– ? Side effects– Escape mutants

• Immunoprophylaxis