The diagnosis of acute hepatitis B was based on recent onset acute illness including prodromal symptoms, jaundice and other typical symptoms. The laboratory investigations supporting the diagnosis of acute hepatitis included the presence of >2.5 times the upper limit of serum alanine aminotransferase (ALT) and serum bilirubin, and positive IgM anti-HBc test. Ultrasound, and esophagogastroduodenoscopy was done to look for any evidence of chronic liver disease. All patients had normal alpha-fetoprotein levels.