30. Epidemiology and prevention of viral hepatitides
Risk factors for hepatitis viruses
- Low socioeconomic status
- Crowding
- Poor sanitation
- Lack of safe water
- IV drug users
- People with many sexual partners
- People who receive regular blood transfusions
Prevention
- Primary
- Hygiene
- Safe handling and disposal of needles
- Provide sterile injection equipment to IV drug users
- Testing donated blood
- Promote safe sex
- Secondary
- Screening high-risk people for cirrhosis, HCC
- Tertiary
- Early and appropriate treatment
Hepatitis A
- Epidemiology
- Especially in tropical countries
- In developing countries most children < 10 have been infected
- Common in those who travel abroad
- Transmission
- Faecal-oral transmission
- Direct contact
- Clinical features
- Young children are asymptomatic
- In developing countries most children are affected before age of 10
- Adults are commonly symptomatic
- Self-limiting, low mortality
- Cannot progress to chronic hepatitis
- Young children are asymptomatic
- Vaccine
- For travellers to endemic areas
- For men who have sex with men
- People with underlying liver disease
Hepatitis B
- Epidemiology
- Causes many deaths worldwide
- Vaccine-preventable disease
- Low prevalence in Europe
- 90% of infected infants develop chronic infection
- 25% of infected infants die
- Transmission
- Vertical
- Blood transfusion
- Sexually
- Between IV drug users
- Clinical features
- Acute infection
- 5 – 10% become chronic
- Diagnosis
- Serology – HBsAg, antibodies
- Prevention
- Promote safe sex
- Needle exchange programmes for IV drug users
- Screening in high-risk groups
- Subunit vaccine
- HBsAg antigen
- Post-exposure chemoprophylaxis
- Passive immunization (immunoglobulins)
Hepatitis C
- Epidemiology
- Mostly found in Africa, East Asia
- Transmission
- Same as Hep B
- Commonly progresses into chronic hepatitis, cirrhosis and HCC
- Screening
- IV drug users
- Patients with HIV
- Health care workers after needlestick injury
- Children of HCV-infected mothers
- Sexual partners of HCV-infected persons
- Treatment
- Antiviral medication can cure 95% of infected people
- Prevention
- No vaccine
- No postexposure prophylaxis
Hepatitis D
- Requires hepatitis B for expression and replication
- Superinfection of Hep D on hep B causes more severe acute illness and more often chronic hepatitis
- Can be prevented with hepatitis B vaccination
Hepatitis E
- Epidemiology
- Common in tropical countries
- Very similar to hep A
- Clinical features
- Cannot progress to chronic hepatitis
- Except serotype 3
- Can cause fulminant hepatitis in people with liver disease or pregnant women
- Cannot progress to chronic hepatitis
- No vaccine available (only in China)