Office of AIDS Programs and Policy

Burden of Disease

Hepatitis A

Worldwide

Hepatitis A virus (HAV) has a worldwide distribution and is common in many developing countries.
In developing countries with poor sanitary conditions (parts of Africa, Asia and Central and South America), infection is usually acquired during early childhood as an asymptomatic or mild infection.
In developing countries where sanitary conditions are variable (Southern and Eastern Europe, some regions in the Middle East), children escape infection in early childhood.
Paradoxically, these improved economic and sanitary conditions may lead to a higher disease incidence as infections occur in older age groups.
In developed countries (Northern and Western Europe, Japan, Australia, New Zealand, USA, Canada) with good sanitary and hygienic conditions, infection rates are generally low. In countries with very low HAV infection rates, disease may occur among specific risk groups such as travelers.

United States (source: Centers for Disease Control and Prevention)

Hepatitis A rates in the United States have declined by 89% since the hepatitis A vaccine first became available in 1995.
In 2006, 3,579 acute symptomatic cases of hepatitis A were reported; the incidence was 1.2 cases per 100,000, the lowest rate ever recorded. After adjusting for asymptomatic infection and underreporting, the estimated number of new infections was 32,000.

Los Angeles County (source: County of Los Angeles, Department of Public Health)

The incidence rate of acute hepatitis A in Los Angeles County has decreased from 3.77 cases per 100,000 in 2006 to 0.80 cases per 100,000 in 2007.
From August 2005 to July 2006, the County sustained a 12 month community-wide outbreak of acute hepatitis A. In 2007 there were no outbreaks identified.

Hepatitis B

Worldwide (source: World Health Organization)

The vast majority of the burden of chronic disease from hepatitis, including long-term sequelae of liver cirrhosis and/or liver cancer, has been attributed to hepatitis B virus (HBV) and has killed about 1.2 million people worldwide.
Approximately 350 million people have chronic hepatitis B infection, with endemic areas primarily in Africa and Asia.
Fortunately, the global burden of hepatitis B should eventually decrease as affordable recombinant subunit vaccines based on the surface antigen of the virus (HBsAg) and effective control strategies are deployed to control the disease on a global basis.
Infants in developing nations begin their HBV immunization at birth. This has resulted in a dramatic reduction of virus transmission in high-risk populations and a decrease in incidence of liver cancer, as seen in China (Province of Taiwan).

United States (source: Centers for Disease Control and Prevention)

In 2006, 4,758 cases of acute hepatitis B in the United States were reported to CDC; the overall incidence of reported acute hepatitis B was 1.6 cases per 100,000 population, the lowest ever recorded.
However, because many HBV infections are either asymptomatic or never reported, the actual number of new infections is estimated to be approximately tenfold higher.
In 2006, an estimated 46,000 persons in the United States were newly infected with HBV.
Rates are highest among adults, particularly males aged 25–44 years.
The rate of new HBV infections has declined by approximately 80% since 1991, when a national strategy to eliminate HBV infection was implemented in the United States.
The decline has been greatest among children born since 1991, when routine vaccination of children was first recommended.
An estimated 800,000–1.4 million persons in the United States have chronic HBV infection.
HBV kills 4000 to 5000 Americans each year.

Los Angeles County (source: County of Los Angeles, Department of Public Health)

The incidence rate for acute hepititis B was at its lowest recorded rate in 2007 at 0.59 per 100,000 cases.
There is insufficient data available to report on the prevalence of chronic Hepatitis B in Los Angeles County.

Hepatitis C

Worldwide (source: World Health Organization)

Hepatitis C has been compared to a “viral time bomb”. The World Health Organization estimates that about 180 million people, some 3% of the world's population, are infected with hepatitis C virus (HCV) of whom 130 million are chronic HCV carriers at risk of developing liver cirrhosis and/or liver cancer.
It is estimated that three to four million persons are newly infected each year, 70% of whom will develop chronic hepatitis.
HCV is responsible for 50–76% of all liver cancer cases, and two thirds of all liver transplants in the developed world.
Disease prevalence is low (< 1%) in Australia, Canada and northern Europe, about 1% in countries of medium endemicity such as the USA and most of Europe, and high (>2%) in many countries in Africa, Latin America, and Central and South-Eastern Asia.
In these higher prevalence countries, figures between 5% and 10% are frequently reported. The extremely high seroprevalence of HCV in the Nile delta of Egypt was found to increase with age from 19% in those 10–19 years of age to about 60% in 30 year-old persons, and is thought to be the major cause of the high prevalence of liver cirrhosis in the country.

United States (source: Centers for Disease Control and Prevention)

Estimated 4.1 million (1.6%) of Americans have been infected.
3.2 million are chronically infected.
About 26,000 new infections occur per year (previously had been an average of 240,000 new infections per year in the 1980s prior to blood donor screening).
8,000 to 10,000 HCV related deaths occur annually and that number may double or triple over the next 10 to 20 years.

Los Angeles County (source: County of Los Angeles, Department of Public Health)

Conservative estimates have been extrapolated from national data.
Over 134,000 people in Los Angeles County have been infected with HCV (National Health and Nutrition Examination Survey and other data).
On average, 800 new HCV infections occur per year (the 1980's average, prior to blood donor screening, was an estimated average of 8,000 new infections per year).
The existing Los Angeles County surveillance system confirmed two acute HCV cases in 2007.