Hepatitis B is a liver disease caused by the hepatitis B virus. As many as 1.25 million people living in the United States have hepatitis B. Not all people who are infected with HBV look or feel sick; they can have the virus and not have symptoms or know they are sick. Hepatitis B can be either "acute" or "chronic."
- Acute hepatitis B virus infection is a short-term illness that occurs within the first 6 months after someone is exposed to the hepatitis B virus. Acute infection can-but does not always lead to chronic infection.
- Chronic hepatitis B virus infection is a long-term illness that occurs when the hepatitis B virus remains in a person's body.
In 2005, the Centers for Disease Control and Prevention (CDC) reported that adults accounted for approximately 95% of the 51,000 new hepatitis B virus (HBV) infections in the U.S., and in 2007 adults accounted for approximately 43,000 new infections with the highest rate reported among at-risk persons ages 25-44 (CDC 2007).
The incidence of HBV infection among adults is attributed largely to risky sexual behaviors and needle-sharing practices (CDC 2006). Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences, including cirrhosis of the liver, liver cancer, liver failure, and death (CDC 2006).
For more information about hepatitis vaccination for children, adolescents or adults, visit our Immunization Division. To find out about clinics providing vaccinations in your area, please call the Adult Viral Hepatitis Prevention Coordinator at 1-866-674-4807 or email the AVHPC program.
Frequently Asked Questions
How likely is it that acute hepatitis B will become chronic?
The likelihood depends upon the age at which someone becomes infected. The younger a person is when infected with hepatitis B virus, the greater his or her chance of developing chronic hepatitis B. Approximately 90% of infected infants will develop chronic infection. The risk goes down as a child gets older. Approximately 25%–50% of children infected between the ages of 1 and 5 years will develop chronic hepatitis. The risk drops to 6%–10% when a person is infected over 5 years of age. Worldwide, most people with chronic hepatitis B were infected at birth or during early childhood.
How common is acute hepatitis B in the United States?
In 2007, there were an estimated 43,000 new hepatitis B virus infections in the United States. However, the official number of reported hepatitis B cases is much lower. Many people don’t know they are infected or may not have symptoms and therefore never seek the attention of medical or public health officials.
Has the number of people in the United States with acute hepatitis B been decreasing?
Yes, rates of acute hepatitis B in the United States have declined by approximately 82% since 1990. At that time, routine hepatitis B vaccination of children was implemented and has dramatically decreased the rates of the disease in the United States, particularly among children.
How common is chronic hepatitis B in the United States?
In the United States, an estimated 800,000 to 1.4 million persons have chronic hepatitis B virus infection.
How common is chronic hepatitis B outside the United States?
Globally, chronic hepatitis B affects approximately 350 million people and contributes to an estimated 620,000 deaths worldwide each year.