Healthcare personnel who have received hepatitis B vaccine and developed immunity to the virus are at virtually no risk for infection. For a susceptible person, the risk from a single needlestick or cut exposure to hepatitis B virus (HBV)–infected blood ranges from 6% to 30% and depends on the hepatitis B e antigen (HBeAg; this is an extracellular form of the core antigen) status of the source individual. Hepatitis B surface antigen–positive individuals who are HBeAg positive have more virus in their blood and are more likely to transmit HBV than those who are HBeAg negative. Although there is a risk for HBV infection from exposures of mucous membranes or nonintact skin, there is no known risk for HBV infection from exposure to intact skin.