Who’s at Risk?
Behavioral/Lifestyle/Medical Risks |
Travelers to areas of high or intermediate endemicity for HAV* and HBV† |
Men who have sex with men |
Persons at increased risk of disease due to sexual practices |
Patients with chronic liver disease, including
— Alcoholic cirrhosis
— Chronic hepatitis C
— Autoimmune hepatitis
— Primary biliary cirrhosis |
Inhabitants of areas of high or intermediate endemicity of HAV with risk factors for HBV |
Patients frequently receiving blood products |
Users of injectable illicit drugs |
Viral hepatitis is known to be caused by at least five different viruses: hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D (HDV) and hepatitis E (HEV). The discovery of a hepatitis G virus has been reported, but its association with liver disease has not been established. The hepatitis A and hepatitis B viruses are the most common causes of acute hepatitis in the United States & Canada.
The hepatitis A virus belongs to the picornavirus family. The viral particle is a nonenveloped RNA virus that usually causes acute, self-limiting disease. However, acute infection can progress to fulminant hepatitis, which causes about 100 deaths per year in the United States.
The hepatitis B virus is an enveloped DNA virus belonging to the family called hepadnavirus. In about 10% of cases, hepatitis B infection leads to a chronic infection, which may be asymptomatic, but can progress to cirrhosis, liver failure, or hepatocellular carcinoma. Each year, more than 250,000 people die worldwide from hepatitis B-associated acute and chronic liver disease. Approximately 1 to 1.25 million Americans are chronic carriers of the hepatitis B virus and an estimated 4,200 to 5,800 Americans die each year from this infection, some due to fulminant hepatitis and others due to cirrhosis or hepatitis B-related hepatocellular carcinoma. Patients with chronic hepatitis B may also serve as a viral reservoir for new infections.
Therefore, both hepatitis A and hepatitis B viruses are significant, both in the United States and abroad. Both infections are associated with morbidity resulting in absenteeism from work and increased health-care expenditures. Also, many people who are at risk for hepatitis A may also be at risk for hepatitis B by virtue of lifestyle or occupational factors.
Currently available monovalent vaccines effectively prevent hepatitis A and hepatitis B but require a total of five injections over a 6-month period to complete a course of immunization (2 doses for hepatitis A vaccine and 3 doses for hepatitis B vaccine).
Hepatitis A Inactivated & Hepatitis B (Recombinant) Vaccine] is the world’s only combination vaccine against both hepatitis A and hepatitis B. It contains both inactivated hepatitis A antigen and recombinant hepatitis B surface antigen (HBsAg). Like the monovalent vaccines, Twinrixis highly immunogenicand causes similarly low rates of local and generalized adverse events. Twinrix is to be given as three doses over a 6-month period and is indicated for persons 18 years of age or older. Twinrix offers more convenience than monovalent hepatitis A and hepatitis B vaccines because patients need fewer injections than if receiving full courses of each monovalent vaccine. Therefore, Twinrix has the potential to improve compliance. Additionally, it could also reduce administrative costs and save vaccine storage space.
For more information on the benefits of Twinrix go to http://www.twinrix.com/
Copyright Pink Triangle Press, 1999
