30. Epidemiology and prevention of viral hepatitides

From greek.doctor

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
  • 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
  • No vaccine available (only in China)