View source for 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, <abbr>HCC</abbr>
* 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)

[[Category:Public health 4 - Preventive medicine]]