Hepatitis B epidemiology and demographics
|
Hepatitis B |
|
Diagnosis |
|
Treatment |
|
Case Studies |
|
Hepatitis B epidemiology and demographics On the Web |
|
American Roentgen Ray Society Images of Hepatitis B epidemiology and demographics |
|
Risk calculators and risk factors for Hepatitis B epidemiology and demographics |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
Overview
Chronic Hepatitis B(HBV) is a global public health issue. According to the World Health Organization(WHO), more than 2 billion people have been infected with HBV. It is a major cause of chronic liver disease worldwide, affecting more than 240 million people. Approximately 25% of carriers develop serious liver disease such as chronic hepatitis, cirrhosis, and primary hepatocellular carcinoma.
Incidence and Prevalence
An estimated one third of the global population has been infected with HBV, and more than 780,000 people die every year from related acute and chronic consequences. Regions with the highest prevalence of HBV include sub-Saharan Africa and East Asia. The infection is usually acquired during childhood in these regions. Approximately 5-10% of adults are chronically infected. Higher rates of chronic HBV is also found in southern parts of Eastern and Central Europe, the Amazon, the Middle East, and India. An estimated 2-5% of the population in the Middle East and Indian subcontinent is chronically infected.
![[1]](http://www.cdc.gov/mmwr/preview/mmwrhtml/figures/r708a1f3.gif){kind=link}
In 2009, there were 38,000 acute HBV cases reported in the U.S. This was the lowest incidence ever recorded at 1.5 cases per 100,000 population. Between 1991 and 2010, the incidence of HBV has decreased by approximately 82%. The decrease was greatest among children largely due to implementation of routine vaccination in 1991.
Although the incidence of HBV is declining in the U.S., it is important to note that reported cases underestimate the true incidence of HBV infection due to the asymptomatic nature of early infections and because of underreporting of symptomatic cases.
Chronic HBV affects an estimated 800,000-1.4 million persons in the U.S. and is responsible for approximately 3,000 annual deaths from associated chronic liver disease.
In the United States, Asian and Pacific Islanders (APIs) make up less than 5% of the total population, but account for more than 50% of Americans living with chronic Hepatitis B. Despite the high rates of infection, many APIs are not tested for Hepatitis B and are unaware of their infection. As a result, chronic Hepatitis B and associated liver cancer in APIs is one of the most serious health disparities in the United States.
Modes of Transmission
The primary method of transmission reflects the prevalence of chronic HBV infection in a given area. In low prevalence areas such as the continental United States and Western Europe, where less than 2% of the population is chronically infected, injection drug abuse and unprotected sex are the primary methods, although other factors may be important.[1] In moderate prevalence areas, which include Eastern Europe, Russia, and Japan, where 2-7% of the population is chronically infected, the disease is predominantly spread among children. In high prevalence areas such as China and South East Asia, transmission during childbirth is most common, although in other areas of high endemicity such as Africa, transmission during childhood is also a significant factor.[2] The prevalence of chronic HBV infection in areas of high endemicity is at least 8%.
Roughly 16-40% of unimmunized sexual partners of individuals with hepatitis B will be infected through sexual contact. The risk of transmission is closely related to the rate of viral replication in the infected individual at the time of exposure.
References
- ↑ Redd JT, Baumbach J, Kohn W; et al. (2007). "Patient-to-patient transmission of hepatitis B virus associated with oral surgery" (PDF). J Infect Dis. 195 (9): 1311&ndash, 4.
- ↑ name="pmid12616449">Alter MJ (2003). "Epidemiology and prevention of hepatitis B". Semin. Liver Dis. 23 (1): 39–46. doi:10.1055/s-2003-37583. PMID 12616449.