Guide to Hepatitis B for People Living With HIV

Section 2: Transmission and Prevention

Coming to terms with your HBV infection sometimes involves telling family members, sexual or drug-use partners, and other people close to you about your status. It may be very helpful for you to know how HBV is transmitted so that you can protect others from exposure and educate them about how to prevent becoming infected.

HBV is transmitted through blood, semen, and other body fluids. HBV is 50-100 times more infectious than HIV and can survive outside the body for up to seven days.

HBV is most commonly transmitted through:

• Birth, from an infected mother to her infant;
• Having unprotected anal or vaginal sex with someone who has HBV; the risk from unprotected oral sex is unclear;
• Sharing drug injection equipment, including needles, cookers, ties, cotton, straws, water, and even measuring syringes;
• Sharing personal-care items that may have blood on them, such as razors or toothbrushes;
• Getting a tattoo with any shared, unsterilized equipment, such as needles, ink, and inkwells;
• Getting a medical procedure with unsterilized equipment; and
• Accidental needlestick injuries or other occupational hazards involving exposure to blood from an infected person.

HBV cannot be transmitted through casual contact such as kissing, shaking hands, hugging, or sharing drinking glasses or eating utensils.

HBV Testing and Vaccination

People who are at risk for HBV infection should get a simple blood test to find out if they have ever been exposed to HBV or if they need to be vaccinated against HBV. The test looks for small pieces of HBV called antigens, and antibodies produced by the immune system to fight off HBV. The tests look for the presence (positive) or absence (negative) of three things:

HBV surface antigen (HBsAg): Small proteins on the surface of HBV.

HBV surface antibody (anti-HBs): Antibody targeting the surface antigen.

HBV core antibody (anti-HBc): Antibody targeting the core antigen.

HBsAg (Hepatitis B Surface Antigen)

HBsAgs are small protein particles on the surface of the hepatitis B virus. HBsAgs can be detected and measured by a blood test. HBsAg testing is commonly used to screen for HBV infection and to diagnose chronic HBV. Test results are usually reported as positive (reactive) or negative (non-reactive), though sometimes in a research setting HBsAg is measured in quantities and reported in IU/mL (international units per milliliter). People who are HBsAgpositive have some level of ongoing HBV viral replication, even when their disease is inactive, and they can transmit the virus to others.

Some people may get a negative result from their HBsAg test but still have detectable hepatitis B virus in their blood. This is called occult HBV. HIV-positive people have a higher rate of occult HBV than people without HIV. It is not clear if occult HBV infection causes liver damage.

It is a good idea for people who are at risk of HBV infection to also be tested for hepatitis C (HCV) and HIV, because these viruses are transmitted in similar ways. There are no preventive vaccines for HCV or HIV, but these viruses are treatable, and in the case of HCV, curable.

HBV Vaccine

The HBV vaccine was created in the early 1980s. It is made with a small part of the virus that is not infectious. Once the vaccine is injected, the immune system responds to the viral particle in the vaccine by producing antibodies that protect against HBV. The vaccine is safe and more than 90% effective in people without HIV; it is given as a series of three shots over a six-month period. Some medical providers will give the first dose of vaccine at the same time as the HBV test, as the vaccine is not harmful to people who are already infected or already have antibody protection, although this practice has not been formally recommended in prevention and treatment guidelines. The HBV vaccine is also available in a combination shot with the vaccine for hepatitis A (Twinrix).

Who Should Get It?

Since the early 1990s, vaccination programs for newborns of mothers with chronic hepatitis B have greatly reduced mother-to-child transmission of HBV. In addition, according to recommendations from public health authorities, the following people should be vaccinated: children; and all those who are at risk for HBV, such as people who have a family member with HBV; health-care workers; people with end-stage renal (kidney) disease who are on dialysis; people with hemophilia (a hereditary blood-clotting disease); HIV-positive people; people who engage in high-risk sexual activities (unprotected vaginal and anal sex); injection drug users; and people with hepatitis C or other types of liver disease.

In the United States, the Centers for Disease Control and Prevention (CDC) also recommends that people born in geographic regions with HBsAg prevalence of greater than 2%, and children of immigrants from these regions should be tested and vaccinated. This includes many countries in Eastern Europe, Asia, Africa, the Middle East, and the Pacific Islands. For a complete list, see: www.cdc.gov/mmwr/preview/mmwrhtml/rr5708a1.htm#tab3.

How Long Does It Work?

The protective effect of the HBV vaccine may wear off over time, so if you were vaccinated more than ten years ago, it is a good idea to ask your doctor to do a test (called an anti-HBs immunizing antibodies titer) to see if you need a booster shot (another shot of the vaccine) to maintain the protection.

Vaccination for HIV-Positive People

All HIV-positive people should be vaccinated against HBV and the hepatitis A virus (HAV) if they have never been infected before. Your doctor can check to see if you need to be vaccinated.

Some HIV-positive people will need to repeat the vaccination series or use a higher dose of the vaccine to produce enough antibodies to protect against HAV and HBV. Because these vaccines require the immune system to be healthy in order for them to be effective, if your CD4 cell count is under 200/mm³, some experts think it may be better to start HIV treatment first and then be vaccinated later, when your immune system is stronger.

After vaccination, be sure to have your clinic check your antibody titer levels annually to see if you have sufficient protection. A booster shot may be needed to restore your antibody titer level.

Preventing Mother-to-Child Transmission

HBV can be passed easily from mother to infant. Globally, the majority of people with chronic HBV were infected at birth. About 90% of babies born to mothers with HBV will become chronically infected. Since mother-to-child transmission of HBV can be prevented, it is important for all pregnant women to be screened for HBV.

Mothers with HBV can protect their babies by making sure that their newborn gets a shot of hepatitis B immune globulin (HBIG -- a product made from blood plasma that contains antibodies that protect against HBV) and the first dose of HBV vaccine within 12 hours of birth. Two to three more shots (depending on vaccination for HBV alone or in combination with other vaccines) are needed to complete the series over the first year. This strategy is about 95% effective in protecting the infant from HBV, but the success rate is lower when the mother has a high HBV viral load. Ask your doctor how many more shots your baby will need and when you should come back to get them.

There has not been sufficient research on the risk of birth defects in infants or on the reduction of transmission with HBV treatment during pregnancy. However, data from the Antiretroviral Pregnancy Registry to date has shown no additional risk of birth defects in infants born from mothers who were on HBV treatment during pregnancy than in the general population.

Pregnant women who are HIV/HBV-coinfected should be on HIV/HBV treatment (see Section 6 on HBV Treatment for HIV-Positive People for more information); this will help prevent the transmission of HIV to the baby. For more information about HIV and pregnancy, see the i-Base guide available online at www.i-base.info/guides/pregnancy/index.html.

Breastfeeding

HBV has been found in breast milk, but studies have shown that it is safe to breastfeed when the baby is vaccinated against HBV at birth; however, since HIV can be passed from mother to infant through breast milk, breast-feeding is not recommended for HIV-positive mothers, although this might not be feasible in poorer countries where infant formulas are not available.

Preventing Sexual Transmission of HIV and HBV

HIV and HBV can both be transmitted sexually via the same body fluids (semen, vaginal fluid, and blood), but different sex acts carry different degrees of risk. For example, mutual masturbation and body rubbing are zero-risk, and oral sex is very low-risk. On the other hand, anal, or vaginal sex without a condom is high-risk. Having a high HIV- and/or HBV viral load (the amount of virus circulating in the blood) increases the risk of infecting one's sex partner with HIV and/or HBV. People with untreated sexually transmitted diseases (STDs, such as herpes, gonorrhea, and syphilis) are more likely to transmit, and more likely to become infected with HIV and HBV. This is because their immune systems might be weakened by the STD infection or they might have open sores. Consistent and correct use of condoms every time you have sex greatly reduces the risk of HIV and HBV transmission.

HBV and Injection Drug Use

The hepatitis B virus can remain alive in syringes and other objects for days. This is why it's important to talk to people you get high with about how to make sure you're getting high safely, and in a way that protects everyone. People who inject drugs should be tested and vaccinated for HBV.

Cleaning syringes with bleach reduces the risk for HIV transmission, but may be less effective in preventing HBV- and HCV transmission. If you're getting high, use a new set of syringes and equipment each time you inject. If you're injecting drugs with other people, mark your equipment and be sure that everyone has his/her own spoon or cooker. Using clean needles and your own works each time you inject stops HIV, HBV, and HCV transmission.