Hepatitis Prevention Advisory

Hepatitis A

Epidemiology:

How is hepatitis A spread?

The virus is spread mainly by oral contact with stool containing the virus.

• If contaminated stool gets into the water or food supply, the virus may infect anyone who drinks the water or eats the food - This is how most people around the world become infected with hepatitis A. In the United States, most people become infected through contact with a household member who has the virus (such as when changing a diaper) or a sex partner who is infected.

• Sometimes large groups of people become infected after eating in a restaurant - This usually happens when an employee with the virus prepares food after not washing his or her hands well after using the bathroom.

• Outbreaks may also occur in day care centers and other facilities which involve close contact.

• In rare cases, hepatitis A can be spread through sexual contact or contact with blood from a person who has the virus circulating in his or her bloodstream. The virus is present in the blood before symptoms appear.

• Transmission through blood transfusions, while possible, seldom occurs.

Who is affected by hepatitis A

Rates of infection with hepatitis A are highest among people who are American Indian or Alaskan Native and lowest among people who are Asian; rates in Hispanic people are higher than those in non-Hispanic people.

In the United States, the rate of hepatitis A infection is 2 to 5 times higher in the West than in the rest of the country; the exact reason for this has not been identified. However, the rates do follow demographic trends. Counties with populations that are 10% or more American Indian have rates 3.5 times higher than counties with smaller American Indian populations; counties with populations that are 15% Hispanic have rates of infection about 2 times higher than counties with smaller Hispanic populations.

About one-third of hepatitis A cases occur in children and adolescents. The CDC collects information on how hepatitis A spreads: In 1995, the most recent year for which information is available: 6.1% of people of reported cases occurred among children or employees in day care centers. 8.7% of people infected were contacts of children or employees in day care centers. 7.5% of people acquired the virus from a sex partner. 8.8% of people had household contact with someone who had hepatitis A. 11.3% of people acquired the virus from other contact with someone with hepatitis A. 2.2% of cases resulted from a suspected food or waterborne outbreak. 6.8% of reported cases occurred among international travelers. Of these, 51% involved trips to South and Central America. 5.0% of cases occurred through injected drug use. 43.6% of cases did not have an identified source of infection.

How can hepatitis A be prevented?

You can prevent HAV infection by vaccination either by: Havrix or VAQTA = which is given in a series of 2 shots. The vaccine usually is 100% effective if you receive both shots before you are exposed to HAV.

A new vaccine (Twinrix) given in a series of 3 shots is available to prevent infection with both hepatitis A and hepatitis B. However, this vaccine should not be given to children under 18. It should be given only when absolutely necessary to pregnant or breast-feeding women because the vaccine's effect in the fetus or newborn is not known.

In addition, you can prevent hepatitis A infection by avoiding:

• Food that has been prepared by someone who is infected with HAV and who has poor hygiene.

• Raw or undercooked shellfish (such as oysters, clams, or mollusks).

• Uncooked food or tap or well water while traveling in foreign countries where hepatitis A is common.

If an outbreak of HAV infection does occur, people who were exposed to the virus should receive a shot of immune globulin (IG) - If you get the shot within 2 weeks of exposure, you probably will not develop symptoms of HAV infection.

General Rule:

You can be infected with HAV only once - After that, you develop lifelong immunity to the virus and cannot become infected again.

Hepatitis B

How HBV is spread

HBV is spread when blood, semen, or vaginal fluids (including menstrual blood) from an infected person enter another person's body, usually in one of the following ways:

• Sexual contact - The hepatitis B virus can enter the body through a break in the lining of the rectum, vagina, urethra, or mouth. Sexual contact is the most important risk factor for the spread of HBV in North America.

• Sharing needles - People who share needles and other equipment (such as cotton, spoons, and water) used for injecting illegal drugs may inject HBV-infected blood into their veins.

• Work-related exposure - People who handle blood or instruments used to draw blood may become infected with the virus. Health care workers are at risk of becoming infected with the virus if they are accidentally stuck with a used needle or other sharp instrument infected with an infected person's blood, or if blood splashes onto an exposed surface, such as the eyes, mouth, or a cut in the skin.

• Childbirth - A newborn baby can get the virus from his or her mother during delivery when the baby comes in contact with the mother's body fluids in the birth canal (perinatal transmission). However, breast-feeding does not transmit the virus from a woman with HBV to her child.

• Body piercings and tattoos - HBV can be spread when needles used for body piercing or tattooing are not properly cleaned (sterilized) and HBV-infected blood enters a person's skin.

• Toiletries - Grooming items such as razors and toothbrushes can spread HBV if they carry blood from a person who is infected with the virus.

In the past, blood transfusions were a common means of spreading HBV. Today, all donated blood is screened for the virus, so it is extremely unlikely that you could become infected with the virus from a blood transfusion.

Contact with a body fluid can occur from sexual contact, sharing needles or other equipment (such as cotton, spoons, and water) to inject illegal drugs, handling blood or instruments used to draw blood, sharing razors or toothbrushes, and getting tattoos or body piercings with needles that were not properly cleaned.

The virus also can be passed from a mother to her newborn baby during delivery (perinatal transmission).

Risk Factors: What Increases Your Risk

People who practice certain behaviors or have certain jobs are at high risk for becoming infected with hepatitis B virus (HBV).

General Rule: If you are a member of a high-risk group, you should receive the hepatitis B vaccine.

Risk factors for hepatitis B that can be controlled include:

• Being sexually active, including having unprotected sex with someone who is infected with the virus or whose sexual history is unknown to you.

• Having more than one sex partner. (Your risk for HBV infection is higher if you have another sexually transmitted disease such as chlamydia)

• Sharing needles or other equipment (such as cotton, spoons, and water) to inject illegal drugs.

• Job and lifestyle risk factors for hepatitis B include: Handling blood or body fluids as a routine part of your job. This includes health care workers, such as doctors, dentists, nurses, and blood and laboratory technicians, and students in these occupations. It also includes morticians and embalmers. Being an employee or resident of an institution for the developmentally disabled. Being an employee or inmate of a long-term prison. Spending more than 6 months in parts of the world where hepatitis B is common or where a large number of people have been infected for a long time with HBV. Such areas include Southeast and Central Asia, the islands of the South Pacific, the Amazon River basin, the Middle East, Africa, Eastern Europe, and China. Being a sexually active homosexual or bisexual man. Living with someone who has long-term (chronic) HBV infection. Getting body piercings and tattoos from a tattoo artist who uses poor infection-control practices.

Risk factors for hepatitis B that cannot be prevented include:

• Recently being infected with a sexually transmitted disease.

• Being born to a woman who is infected with HBV (if the newborn doesn't promptly receive the hepatitis B vaccine and hepatitis B immune globulin). However, breast-feeding does not transmit the virus from a woman with HBV to her child.

• Having once lived in a part of the world where hepatitis B is common.

• Being bitten by a person who is infected with HBV. (Note: HBV is not spread by kissing.)

• Having a blood-clotting disorder, such as hemophilia, that requires you to receive clotting factors from human donors.

• Having severe kidney disease that requires you to have your blood filtered through a machine (hemodialysis).

Statistics:

Although in the United States hepatitis occurs mainly in people who are in one of the high-risk groups listed above, 30% to 40% of those who become infected do not have an identifiable reason for their infection. People with hepatitis B who engage in high-risk behavior (such as having multiple sex partners or injecting illegal drugs) are at increased risk for hepatitis C and HIV, the virus that causes AIDS.

Prevention

Vaccination to prevent the spread of HBV infection is up to 95% effective. Although the vaccine is not widely used among adults, those at risk for infection (such as medical personnel who work with body fluids or people who have multiple sex partners) should be vaccinated.

Most countries require childhood immunization against hepatitis B.

You can protect yourself from hepatitis B virus (HBV) infection by avoiding contact with the body fluids of someone whose health and sexual history are not known to you. To prevent infection: Use a condom when you have sex. Don't share needles. Wear latex or plastic gloves if you have to touch blood. Don't share toothbrushes or razors.

Hepatitis C

Hepatitis C is caused by the hepatitis C virus (HCV), which multiplies in liver cells. In 10% of people who become infected with HCV, the cause of infection is never known.

How does hepatitis C spread?

The hepatitis C virus (HCV) spreads through contact with blood, most commonly by sharing needles and other equipment used to inject illegal drugs. Health care workers face a risk (although low, less than 2%) of infection from accidental needle sticks and other occupational exposures. The virus can spread through sexual contact, but the risk is low, especially for long-term monogamous couples.

Risk increases for those who have multiple sex partners. Having a sexually transmitted disease or being infected with HIV may increase the risk of becoming infected with HCV. In the past, the virus was spread through infected blood used in transfusions and infected solid organs used in transplantation. However, the risk of infection from these procedures is now extremely low; since 1992, blood and organs have been routinely screened for hepatitis C. An infected mother can spread the virus to her baby at birth. The transmission rate is about 6% and can be higher if the mother also is infected with HIV.

The virus spreads through blood:

• Sharing needles and other equipment (such as cotton, spoons, and water) used to inject illegal drugs is the most common way HCV is spread.

• The virus also can be spread by sexual contact, but the risk is low, especially for long-term monogamous couples. The risk increases if you have many sex partners or if one partner is infected and bleeding occurs as a result of sexual activity. Having a sexually transmitted disease or being infected with HIV may increase the risk of HCV infection.

• Household contact with a family member who has hepatitis C is not a common means of spreading the illness.

• Pregnant women infected with the virus can give hepatitis C to their babies. The risk is about 5%. The risk is higher if the woman also is infected with HIV.

• Studies show that HCV does not spread from a mother to her baby through breast milk. However, breast-feeding women should make sure their nipples are not cracked or bleeding.

• In the past, hepatitis C sometimes was spread through blood transfusions. Since 1992, all donated blood has been screened for HCV, so the possibility of becoming infected from a blood transfusion is very low. Solid-organ transplant (such as a kidney, liver, or pancreas) from a donor infected with HCV used to be a source of infection. Now, however, all donor organs are screened for HCV infection, so the risk of becoming infected with HCV in this manner is very low.

Risk Factors: What Increases Your Risk

Certain factors may increase your risk of becoming infected with hepatitis C virus (HCV).

Risk factors you can control:

• Sharing needles and other equipment (such as cotton, spoons, and water) used to inject or take illegal drugs

• Having more than one sex partner or having unprotected sex with someone who has many sex partners. The risk is even higher if you are infected with a sexually transmitted disease or HIV

• Having sex with a partner who has HCV infection. However, long-term spouses of people who have ongoing (chronic) HCV infection have a low risk of infection. Still, the risk is not zero. Such couples may want to use condoms.

• Having your ears or another body part pierced or having a tattoo made with unsterilized equipment; infection rates from body piercing and tattooing are less than 1%.

• Receiving acupuncture with needles that have not been properly sterilized

• Working in a health care environment in which you are exposed to fresh blood or where you may be pricked with a used needle. (Hospitals have established standard precautions for protecting yourself against exposure to HCV; the risk of infection from needle sticks is about 2%.)

Risk factors you cannot control:

• Needing to have your blood filtered by a machine (hemodialysis) because your kidneys are unable to perform this function

• Giving birth when you are infected with HCV. The risk of passing the virus to your child is greater if you also are infected with HIV, which causes AIDS

• The following also are risk factors that you cannot control, however, the risk of becoming infected with the virus in these ways is extremely low - These risk factors include: [a] Living with someone who is infected with hepatitis C. [b] Receiving blood, blood products, or a solid organ (kidney, liver, pancreas) from a donor. In 1992, screening of all blood, blood products, and donor organs for HCV became a requirement, making transfusion and organ transplants uncommon causes of HCV spreading. [c] Receiving blood-clotting factor concentrates (used to treat the blood disorder hemophilia). In 1987, screening of clotting factor concentrates became a requirement, making transfusion of clotting factor concentrates an uncommon cause of HCV spreading.