Epidemiology

You are not alone
Hepatitis is considered one of the most prevalent health problems of the 1990s. The World Health Organization reports that 1.4 million cases of hepatitis A are treated annually worldwide. In the United States, close to 5 million adults have hepatitis B or C, and this may be only a small percentage of the total of infected individuals.

Hepatitis A: Hepatitis A (HAV), the most prevalent type of hepatitis worldwide, strikes more than 150,000 people in the United States annually.

Hepatitis B: Each year, more than 250,000 people contract hepatitis B (HBV) in the United States.

Hepatitis C: The Centers for Disease Control and Prevention (CDC) estimates that up to 30,000 individuals acquire hepatitis C (HCV) infections in the United States each year. In other parts of the world, the rates of infection and numbers in infected individuals range as high as 20 percent of the population. Called "an emerging public health threat" and the "silent epidemic," hepatitis C is a leading cause of cirrhosis and liver cancer, and is now the leading reason for liver transplantation in the United States.

Risk factors

Major risk factors for hepatitis A
The CDC lists household or sexual contact, day care attendance or employment, and recent international travel to areas with poor sanitation as major known risk factors for infection with hepatitis A. Eating food prepared by infected food handlers and using contaminated needles are other risk factors.

Major risk factors for hepatitis B
In the United States, the major risk factors for hepatitis B are unprotected sex with multiple partners and intravenous (IV) drug use.

Major risk factors for hepatitis C
The major risk factors for acquiring hepatitis C are IV drug use and transfusion of blood or blood products prior to 1992. Other risk factors also contribute.

A complete list of risk factors for acquiring hepatitis A, B, and C is provided in the following table.

Major risk factors for hepatitis A, B, and C

HEPATITIS A

Person-to-person contact
Poor personal hygiene
Poor sanitation
Unsafe sexual practices
Employment of contact with day care centers and healthcare institutions such as nursing homes
Street drug use

HEPATITIS B

Hemodialysis
Patients of custodial institutions for developmentally disabled
Exposure to blood/blood clot products
Needle-stick injury
Sexual activity with multiple (heterosexual or homosexual) partners
IV drug use
Infants of HBV-positive mothers
Tattooing
Body piercing

HEPATITIS C

Hemophilia
Hemodialysis
Organ transplant
IV drug use
Blood transfusion prior to 1992
Needle-stick injury
Tattooing
Body piercing
Sexual activity with multiple partners

About 40 percent of people with hepatitis C have a history of IV drug use. Another 40 percent do not know the source of infection. The remaining 20 percent of hepatitis C cases may be attributed to household contact with a person known to have hepatitis, sexual contact with multiple partners, transfusion-associated disease, or occupational exposure.