The highest rates of hepatitis B virus (HBV) infection are among intravenous drug users and homosexual men.
+Hepatitis B surface antigen (HBsAg) has been detected in saliva, semen, stool, and urine, but not in tears or vaginal secretions.
+The typical interval between exposure and onset of clinical illness is between 1 and 3 weeks.
+Approximately 25% of adults infected with HBV become chronic carriers of HBsAg.
+Health care workers who routinely come in contact with blood have a prevalence of HBsAg of more than 5%.
Hepatitis B virus (HBV) is principally transmitted by parenteral exposure but can also be transmitted by intimate contact, with highest rates of infection among IV drug users and men who have sex with men. HBsAg has been detected in saliva, semen, stool, tears, urine, and vaginal secretions. The typical interval between exposure and onset of clinical illness is between 60 and 90 days, but serologic markers of infection generally appear within 1–3 weeks. Approximately 10% of adults and 90% of neonates who are infected with HBV become chronic HBsAg carriers. Health care workers who routinely come in contact with blood have a prevalence of HBsAg of 1–2%.