Hepatitis B

Hepatitis B is the most common preventable infectious disease in the United States. It’s estimated that there are 200,000 to 300,000 cases each year, of which only about 15,000 are reported. About 1 million Americans are chronic carriers—they are infected and infectious for the rest of their lives. Almost 6,000 people in the United States die each year from acute hepatitis B or complications of hepatitis B infection. It is prevented by receiving hepatitis B vaccine in a three-dose series.

How Do You Get It?

Hepatitis B virus (HBV) is carried in the blood and spread by contact with infected body fluids, especially blood. It is transmitted in much the same way as HIV, the AIDS virus, but hepatitis B is much easier to catch. A drop of hepatitis B-infected blood contains hundreds of thousands of virus particles, more than enough to infect someone. In contrast, a drop of HIV-infected blood contains only between 10 and 100 virus particles, which is not enough to infect anyone.

The virus is sturdy, meaning it can survive on dried surfaces for days. Hepatitis B virus must get into your bloodstream to infect you, which it can do in many ways— through sexual contact, blood transfusions, injection with dirty needles, or sharing toothbrushes, razors, or eating utensils. More than half the cases result from sexual intercourse with an infected partner.

In the hospital both dialysis patients and workers are at risk. Many other healthcare workers have become infected from needle sticks, lab accidents, or blood splashes in the emergency or operating room. Dentists have caught hepatitis B from patients, and infected dentists have given it to patients.

Infected mothers transmit hepatitis B to their babies during the last three months of pregnancy, during delivery, or through breast-feeding. Mothers infected early in pregnancy who do not become chronic carriers have less risk of giving it to the fetus. All pregnant women should be tested for hepatitis B.

The following groups of people are at risk of getting hepatitis B:

■ Anyone whose work puts them in contact with blood: doctors (especially surgeons), nurses, operating and emergency room staff, lab technicians, ambulance workers, fire fighters, police, blood bank workers, patients and staff in hemodialysis units, dentists, and dental hygienists
■ People who require frequent or large blood transfusions
■ Residents and staff of institutions of the mentally handicapped
■ Prisoners
■ IV drug abusers
■ People with multiple sex partners
■ Sexually active homosexual men
■ People from areas of the world where hepatitis B is common: parts of Africa, Asia, Alaska, the Caribbean Islands, and Pacific Islands
■ Travelers who plan to spend more than six months in these areas
■ People who have household or intimate contact with an infected person, including households with adopted children from areas where hepatitis B is common.

How Do You Know If You Have It?

About half of those infected become jaundiced, yet many people have very few noticeable symptoms. When symptoms occur they come on gradually and include tiredness, nausea, vomiting, joint and muscle aches, mild abdominal pain in the upper right side, poor appetite, and mild diarrhea for three to ten days, followed by jaundice, light-colored stools, dark urine, and itchy skin for one to three weeks. Once jaundice appears, you usually feel better. Infants infected at birth by their mothers will have no symptoms.

Tests

Hepatitis B is readily diagnosed with blood tests. Liver function tests measure enzymes produced by the liver. These enzymes will be elevated in all forms of hepatitis. Several other tests, known as markers, differentiate hepatitis B from other hepatitis infections. The tests that are usually used look for the hepatitis B antigen or antibody:

■ Hepatitis B surface antigen (HBsAG). The infectious outer coat of the virus is called the surface antigen. If you are infected with hepatitis B, your blood will be positive for hepatitis B surface antigen, or HBsAG.
■ Hepatitis B surface antibody (anti-HBsAG). If you are immune to hepatitis B either through previous infection or vaccination, your blood will be positive for antibody to hepatitis B surface antigen. The antibody is called anti-HBsAG.
Three other markers are used to determine if you have a recent or chronic infection and how infectious you are:
■ Hepatitis B e antigen (HBeAG). E antigen is another infectious particle on the virus. This antigen is present early in the infection and then disappears. If it persists you have a much higher chance of becoming a chronic carrier who never gets over hepatitis B. People with e antigen are much more infectious to others than those who lack this antigen. If you have it, your blood test will be positive for HBeAG. If you have developed immunity to this antigen, your blood test will be positive for the antibody, anti-HBeAG.

Hepatitis B core antibody (anti-HBc-IgM). Core antigen is the infectious core of the virus that infects the middle of the liver cells and therefore is not found in blood. This antigen is also present early in the infection, but is not detected in Iblood tests. However, blood tests can find antibodies to this antigen. By the time you have symptoms you have made antibodies. If you have recently been infected with hepatitis B, your blood test will be positive for the antibody, anti-hepatitis B core IgM (anti-HBc-IgM). IgM antibodies represent very recent infection and do not last. This is an important test during the “core window” phase, a four-week period when the surface antigen has disappeared from the blood, but the surface antibody has not yet appeared. People in the core window phase are still infectious, but standard hepatitis B blood tests will not show this.

Total antibody (anti-HBc-total, or core lgG). This test measures total antibody to core antigen. It indicates past infection and is a lifelong marker. If you have this antibody, your blood will be positive for anti-hepatitis B core total (anti-HBc-total, or core IgG). Most people who have recovered from hepatitis will have core antibody. If you are a chronic carrier, your blood will be positive for both surface antigen and core antibody, or HBsAG and anti-HBc-total.

How Sick Will You Be?

Most people aren’t very sick, but some are quite sick for several weeks. People older than 40 will have more severe illnesses. Children have few symptoms. Rarely, hepatitis B becomes fulminant hepatitis.

Incubation Period

The incubation period ranges from six weeks to six months.

Infectiousness

Once you have antibodies in your blood, you are no longer infectious. You are most infectious just before you develop symptoms—when you are not even aware of your infection. People who become chronic carriers do not develop antibodies and are always infectious, even though they may feel fine.

Immunity

Those who recover from infection are immune for life.

Complications

People who recover from infection and develop antibodies are at no more risk for long-term complications than someone who was never infected. We worry about infected babies and children, and the five percent of adults who become carriers.

Chronic carriers have a 100 times greater risk of developing liver cancer, which is almost always fatal. They are also at great risk of developing cirrhosis of the liver as a result of slow and continuous damage by the virus. (Damage by alcoholism can also cause cirrhosis, in which case it is called alcohol-related cirrhosis.) Cirrhosis can be fatal. Some people are saved by liver transplants.

Babies born to infected mothers have a 10 to 85 percent chance of being born infected, and those that are have a 90 percent chance of becoming chronic carriers and thus a high chance of developing either cirrhosis or liver cancer when they grow up. Twenty-five percent will die of liver disease as adults.

How Do You Treat It?

Alpha-interferons are artificially produced infection-fighting proteins. They are approved for use in people with chronic hepatitis B or C infection. Chronic hepatitis B infection means you have had hepatitis B surface antigen and e antigen in your blood for at least six months, your liver enzymes are at twice the normal level, and a liver biopsy (removal of a very small piece of your liver for study under the microscope) would reveal ongoing liver destruction. And yet you may feel fine.

You receive four months of injections either daily or three times a week. Most people learn to give their own injections. The injections cost about $75 a week. About 40 percent of recipients will respond to this treatment. Their liver functions return to normal, they lose the e antigen, and no further damage is done to their livers. Although some people will relapse after stopping treatment, many respond well to a second course of interferon treatment. In those who respond, alpha-interferon stops hepatitis B virus from reproducing in the liver, but it is not yet known whether it eradicates the virus.

Many people report unpleasant short-term side effects, such as fever, chills, appetite loss, vomiting, muscle aches, and sleep problems. These side effects usually disappear after a few weeks if you continue with the injections. Some older people and those with cirrhosis may have serious long-term side effects appearing one to three months after beginning interferon, including bleeding abnormalities and serious depression. You must report all side effects to the doctor prescribing the medicine, who can decide whether to change your dosage or discontinue the drug.

Nursing Care

During recovery, you need bed rest and a high-carbohydrate, low-fat diet. After you’ve recovered, be sure to have your blood rechecked by your doctor to determine if you have developed antibodies. If not, you may become a chronic carrier and will need medical follow-up. People who become chronic carriers never develop antibodies and should have blood tests to determine if they carry the e antigen. A person who is e antigen positive is extremely infectious and at higher risk of developing complications. About ten percent of chronic carriers will lose the e antigen each year. Chronic carriers need regular checkups, including liver function tests. Household members should be tested and, if not already infected, must receive the vaccine.

How Do You Prevent It?

Vaccine

Hepatitis B is a completely preventable disease, but thousands of people continue to get the disease every year. When the vaccine first came on the market in 1983, it was made from treated human plasma. Because its appearance coincided with the beginnings of the AIDS epidemic, many people feared receiving a vaccine made from human blood products, thinking there may be a risk of getting infected with the AIDS virus. The vaccine proved to be perfectly safe, however, and no cases of AIDS ever resulted from hepatitis B vaccine. A few years later a vaccine made from entirely synthetic products came on the market. It is called Recombivax because it is produced with recombinant DNA. Another synthetic vaccine was introduced in 1991 called Engerix-B. Either of these vaccines gives complete protection after three doses. You get the second dose one month after the first, and the third dose six months after the first dose. For more rapid protection, Engerix-B is given in a three dose schedule at 0, one month, and two months, with a fourth booster dose 12 months after the first dose. Travelers often choose this schedule.

Anyone who is at risk of getting hepatitis B, including all medical and nursing students, should receive the vaccine. As of November 1991, the vaccine has been recommended for all infants as part of their routine childhood immunizations. It is given at birth, at one month, and at six months of age. Booster shots are currently not recommended. However, this will be reevaluated when the current crop of immunized children reach adolescence.

In British Columbia, Quebec, and Ontario hepatitis B vaccine is now routinely offered to fifth, sixth, and seventh grade students, but is not part of routine infant immunizations in Canada.

Many parents and doctors have been reluctant to include hepatitis B in their routine childhood immunizations. Some think it’s too expensive; others don’t understand why it’s important. But if a potentially deadly disease is preventable and the vaccine has proved safe and effective for many years, why not prevent it?

Postexposure Protection

Pooled human blood plasma containing high levels of hepatitis B antibodies, called HBIG, is available for unimmunized people. If you have sexual contact or blood exposure to someone who is infected with hepatitis B, you will be 90 percent protected if you receive HBIG within seven days of exposure and begin the hepatitis B vaccine series at the same time.

Babies born to infected mothers must receive HBIG within 12 hours after birth to be protected. The vaccine series must be started at the same time. These babies should be tested at 12 to 15 months of age to see if they are infected or immune. If they are immune, then the preventive measure worked.
See also hepatitis.