1. The virus that does not cause chronic liver disease
Hepatitis A
The virus that does not cause chronic liver disease

2. Hepatitis A “Infectious Hepatitis” First characterized in 1973
Detected in human feces
Hepatovirus genus
A reportable infectious disease
U.S. rate of infection 4/100,000
Highest among children

3. Risk Factors Sexual or household contact International travel
Men who have sex w/ men (MSM)
Intravenous drug abuse (IVDA)
Daycare

4. Transmission Unwitting contact w/ infected person Most cases unknown
Primary route is fecal oral either by person to person contact or ingestion of contaminated food or water

5. Pathogenesis
After ingestion, the HAV survives gastric acid, moves to the small intestine and reaches the liver via the portal vein
Replicates in hepatocyte cytoplasm
Not a cytopathic virus
Immune mediated cell damage more likely
Once mature the HAV travels through sinusoids and enters bile canaliculi, released into the small intestine and systemic circulation, excreted in feces

6. Clinical Features Incubation is usually 2 to 4 weeks, rarely 6 weeks
Complete recovery within 2 months for > 50%
Within 6 months for almost all others

7. Clinical Features Low mortality in healthy people High morbidity
High mortality when older than age 60
High in presence of chronic liver disease
High morbidity
Around 20% need hospitalization
Lost work days
Most become jaundiced

8. Clinical Features Asymptomatic < 2 year old
Symptomatic – 5 and older ill about 8 weeks
Cholestatic – jaundice lasts > 10 weeks
Relapsing w/ 2 or more bouts acute HAV over a 6 to 10 week period
Acute liver failure – rare in young. When it occurs, is rapid i.e., within 4 weeks

9. Signs and Symptoms
Prodrome lasts 1-2 weeks: fatigue, asthenia, anorexia, nausea, vomiting, and abdominal pain
Less common: fever, cephalgia, arthralgia, myalgia, and diarrhea
Dark urine is followed by jaundice and hepatomegaly
Less common: splenomegaly, cervical lymphadenopathy

10. Diagnosis During acute infection, anti HAV IgM appears first
HAV IgG antibody appears early in the course of infection and remains detectable for life, providing lifelong immunity

11. Prevention Immunization
All children 12 – 24 months
Travelers, occupational exposure risk
All patients w/ hepatitis B or C or those awaiting liver transplantation
HIV positive patients
MSM
IVD users

12. Immunize People w/ clotting factor deficiencies
Lab workers handling live hepatitis A vaccine
Need for post exposure prophylaxis uncommon. Administration of the vaccine is effective. If needed, administer immune serum globulin within 2 weeks 0.02 ml/Kg IM

13. Hepatitis A Vaccine The vaccine is inactivated HAV
Schedule for 2 – 18 years depends upon the manufacturer:
Havirx: 720 EL 0, 6-12 mo
Vaqta: 25 0, 6-18 mo

14. Hepatitis A Vaccine For those over age 18:
Havirx: 1440 EL 0, 6-12 mo
Vaqta: 50 0, 6-18 mo
Adverse effects: rarely anaphylaxis, injection site induration, erythema, edema, fatigue, mild fever, malaise, anorexia, nausea
Twinrix:
720 El U/1mL 0, 1, 6 mo plus
20 mcg HBV