"The HAVRIX vaccine provides protection against hepatitis A infections (Innis 1994). However, hepatitis A is not endemic in the United States. Hepatitis A is also spread by the fecal-oral route; therefore, improvements in hygiene and sanitation significantly reduce infection (CDC 2006). Nevertheless, some individuals are at risk for hepatitis A infections, which can cause severe liver disease, presenting a grave inconvenience imposing vaccination. These include those traveling to areas where hepatitis A virus is endemic, men who have sex with men, intravenous drug users, those with clotting disorders, those working with nonhuman primates, and those having sexual intercourse with someone who has hepatitis A (CDC 2006)"