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Hepatitis B
Hepatitis B virus (often known as HBV, but to avoid possible confusion with HIV, this abbreviation isn’t used in this booklet) is an infection that can cause severe damage to your liver, sometimes resulting in death.
It is a very common infection around the world, particularly in Africa, the Indian sub-continent, and throughout the rest of Asia. Many gay men with HIV are also infected with hepatitis B. Hepatitis B infection is also common in people who inject drugs. Between 5 and 10% of people diagnosed with HIV are also infected with hepatitis B or hepatitis C. This is often called co- infection. ขอขอบคุณ นายแพทย์ ศัลยวิทย์ จิตต์มิตรภาพ Transmission The reason why so many people with HIV have hepatitis B is because it can be spread in a similar way to HIV, by contact with infected body fluids like blood, semen and vaginal fluid, and from a mother to her baby during pregnancy or delivery. Although small amounts of hepatitis B virus can be found in saliva, saliva is not likely to spread the infection, unless saliva from an infected person gets into a cut or sore. In richer countries, such as the UK, hepatitis B has mainly affected gay and bisexual men, and injecting drug users. Increasing numbers of cases are being seen in people who have come to the UK from Africa and India. Hepatitis B is more infectious than HIV. Like HIV, it is possible to reduce the risk of becoming infected with the hepatitis B virus. It is important that people with HIV are vaccinated against hepatitis B unless they are already immune (see below: Stage 4 - immunity to hepatitis B). Using a condom for anal, vaginal and oral sex reduces the chances of hepatitis B being passed on during sex. Similarly, you should never share needles or other injecting drug equipment. Blood products in the UK are routinely screened for hepatitis B. Symptoms The majority of adults who are infected with hepatitis B have no symptoms to suggest that they have the infection, and it is often only diagnosed by routine blood tests and monitoring of the health of the liver. Even if you have no symptoms at all, you can still pass on the virus to others. However, symptoms may occur soon after infection. These can include some of the following: • A yellowing of the skin and whites of the eyes (jaundice). • Loss of appetite. • Pain in the stomach. • Nausea and vomiting. • High temperature. • Joint and muscle aches and a general feeling of being unwell. These symptoms can be severe and, in some rare cases, can cause death. Stages of infection There are four stages of hepatitis B infection. Stage 1 – Immune tolerance At this stage the hepatitis B virus is able to reproduce freely in the body but does not cause any symptoms or liver damage. In adults, this stage tends to last for several weeks after infection with hepatitis B. In babies and small children, it can last for several years after infection. Stage 2 – Immune response During this stage the immune system (the body’s natural defences), attacks the hepatitis B-infected cells in the liver and starts to clear the infection from the body. In some people, this phase may last for just a few weeks. However, in people whose immune system cannot clear the infection, it can last for years. The immune system attacks those cells in the liver that are infected with hepatitis B virus. This causes liver damage and many people develop symptoms and become unwell at this time. Stage 3 – Viral clearance This stage is often also known as ‘seroconversion’. The body produces antibodies in response to a substance on the surface of the hepatitis B virus called the e-antigen. During this stage, hepatitis B stops reproducing. Stage 4 – Immunity to hepatitis B This is when the immune system produces a full antibody response to hepatitis B, and clears the body of hepatitis B virus. Hepatitis B genetic material (DNA) may, however, remain inside the liver cells and can, on rare occasions, reactivate at a later date. Most adults infected with the hepatitis B virus recover fully and develop lifelong immunity. However, up to 10% of people infected as adults will become chronic carriers of the virus. This means that they will continue to be infectious to others and can develop serious, long-term liver damage. Infected children, especially newborn babies, are much more likely to become chronic carriers. People with HIV are also less likely to clear the virus. Monitoring There are a number of tests you can have to see if you are infected with hepatitis B, or if you have been infected and have managed to clear the infection. If the tests find fragments of the hepatitis B virus (called surface antigens) over a period longer than six months, then you are a chronic carrier of hepatitis B and continue to be potentially infectious to other people. People who test positive for the hepatitis B e-antigen as well have higher rates of replication of hepatitis B and are also more likely to be infectious. If you have antibodies, but no surface antigen, after six months of infection, then your immune system has cleared hepatitis B infection. If infected, you should also have regular tests to see if your liver has been affected by hepatitis B. These are called liver function tests and they look at levels of certain chemicals, proteins and enzymes, which give an indication of how well your liver is working and whether there is ongoing damage to the liver. They should be performed at least every six months. Ultrasound examinations are sometimes used to see how much damage has been done to the liver, but in some cases it may be necessary to perform a liver biopsy. This is when a tiny sample of tissue from the liver is extracted (using a hollow needle) for examination under a microscope. Treatment Treatments are available if your body does not clear infection with hepatitis B itself. The aims of hepatitis B treatment include reducing liver inflammation and the amount of hepatitis B DNA. Ideally, treatment will also remove all hepatitis B antigens from the body and produce antibodies. Several drugs are currently available for the treatment of hepatitis B. These are adefovir (Hepsera), interferon alfa, entecavir (Baraclude), and telbivudine (Sebivo). A number of anti-HIV drugs have good activity against the hepatitis B virus: • 3TC (lamivudine, Epivir, called Zeffix when used to treat hepatitis B without HIV therapy) • FTC (emtricitabine, Emtriva) • tenofovir (Viread, also available in a combined pill with FTC called Truvada). Many HIV doctors will use these drugs to treat both HIV and hepatitis B in co-infected patients. The type of treatment you receive will depend on how both hepatitis B and HIV are affecting your health. It’s very important that the drugs that also work against HIV aren’t taken unless they are part of an HIV treatment combination. This is because otherwise they may be taken in a way that causes your HIV to become resistant to them. Before starting any course of treatment, you’ll be intensively monitored to check the health of your liver, and your CD4 cell count and viral load. As a general rule, your choice of hepatitis B treatment will be guided by your CD4 cell count. If you have a CD4 cell count below 350: HIV treatment is recommended at this level. Therefore, the combination of drugs you are given should work against both HIV and hepatitis B. The most widely used option is a pill combining FTC and tenofovir called Truvada, also available in the combination pill Atripla. If you have a CD4 cell count between 350 and 500: People with hepatitis B are one of the groups of patients for whom earlier HIV treatment may be appropriate. Therefore, a combination of drugs that are active against both viruses (for example, a combination that includes Truvada) should be used. CD4 cell count above 500: Early HIV treatment is an option. An alternative is the use of hepatitis B drugs that do not work against HIV: either pegylated interferon or adefovir. Entecavir should not be used without antiretroviral drugs because it can cause cross-resistance to the HIV drug, 3TC (lamivudine, Epivir). HIV treatment and hepatitis B HIV treatment can be used safely and effectively if you have hepatitis B. However, when some people infected with HIV and hepatitis B start taking HIV treatment, they may experience a short-term flare-up of liver inflammation. This is usually the consequence of the HIV treatment restoring the immune system, which then becomes better at responding to infections such as hepatitis B. This improved immune response can lead to active liver inflammation as a result of hepatitis B disease. People with hepatitis B appear to be at greater risk of experiencing the increases in liver enzymes which some anti-HIV drugs can cause. The drugs particularly associated with liver side-effects include ddI (didanosine, Videx, Videx EC), lopinavir/ritonavir (Kaletra) and darunavir (Prezista). The health of your liver will be closely monitored after you start treatment. You can find out more about the type of tests that will be done to monitor the health of your liver in NAM’s patient information booklet, CD4, viral load and other tests. Personal health inquiries and information about STDs: these Channels Resources NAM |
