Hepatitis A

Hepatitis A is a DNA virus and is responsible for common acute hepatitis amongst the young and travellers.

Hepatitis A is a DNA virus and is responsible for common acute hepatitis amongst the young and travellers. Only 30% of patients ever develop frank jaundice. The other 70% often feel like they have a simple severe flu. The height of the ALT is not a marker of severity of hepatitis, only the bilirubin level indicates severity. A particular distaste for meat and cigarettes is a common symptom in prodromal acute hepatitis A. Nearly all patients recover without any significant sequelae. 0.01% of patients develop a fulminant course of hepatitis which may require liver transplantation. An unusual complication is a relapsing jaundice and cholestasis which may rarely follow a seemingly recovered acute hepatitis A infection. This usually requires a short course of steroids otherwise the patient can become extremely debilitated with pruritus and jaundice. Hepatitis A never causes cirrhosis. Infectivity ceases at the onset of jaundice or shortly after the peak ALT liver enzyme response.
Primary prevention is achieved through vaccination. This gives adequate immunity in about 93% of cases for up to 4 years with an inactivated vaccine. The first injection can give adequate antibodies in about 90% of cases from about 4 weeks after vaccination. A booster injection is required 6-12 months later for a more durable response. Secondary prevention is through hyper-immune globulin. It has to be administrated to close contacts within the 14 day incubation period after potential exposure. A natural wild-type Hepatitis A infection gives life long immunity.