I researched about this topic and reposted this from: http://aids.about.com/od/vaccinesscreenings/a/hepbdd.htm
So why is hepa B vaccination important to us pozzies?
Because the risk factors for HIV and hepatitis B infection are similar, HIV practitioners highly recommend the hepatitis B vaccine for those people living with HIV. In fact, hepatitis b vaccination is becoming a standard part of most everyone's immunization schedule starting with babies. In people with normal functioning immune systems, the hepatitis b vaccine will typically cause the body develop an immune response to hepatitis B, preventing infection. Unfortunately, in people with weakened immune systems such as people living with HIV, the vaccine doesn't always work as intended and the body's defenses do not form protective antibodies. In these cases double-dosing of the hepatitis b vaccine is often done in an attempt to illicit an immune response. And in many cases the results are favorable.
How Does a Vaccine Work?
When any infectious organism enters your body, the proteins of that organism stimulate your body's defenses to produce antibodies that will fight off the organism. In addition, memory cells are also produced which remain well after the organism has been eradicated from the body. It's these memory cells that recognize the organism the next time it enters the body and dispatches existing antibodies that prevent another infection.
Simply put, a vaccine fools the body into thinking it has been infected. The body believes infection has occurred and begins to produce antibodies and memory cells to fight the infection. In the case of hepatitis b vaccine, the body believes it has been infected with hepatitis b, so it produces antibodies to fight that infection. In the future, if an actual hepatitis b exposure does occur, the antibodies that have been produced as a result of the vaccine prevent hepatitis b infection.
When Vaccines Don't Work
In order for vaccines to be effective, they must trigger the body's immune response . In the case of a healthy, normal functioning immune system, this will occur most of the time. But in people who have weakened immune systems, such as people living with HIV, the immune response might not occur, meaning antibodies that protect the person from infection are not produced, in turn leaving the person susceptible to infection. In the case of the hepatitis b virus, the vaccine might not trigger the immune response and therefore the person is not protected against hepatitis b infection.
Double Dose Hepatitis B Vaccine May Help
In the HIV program I work in, if there is no immune response to the hepatitis b vaccine, we try a second series of hepatitis b vaccine, but double the standard dose. Studies have shown and my experience in our clinic shows that giving a double dose of the hepatitis b vaccine series often will elicit an immune response in people who didn't respond to conventional hepatitis b vaccine dosing. The standard vaccine dose is a series of three 20 microgram (mcg) doses; one at month 0, another 1 month later, and the final dose 5 months after the second (all doses must be given within 6 months for optimal effectiveness). About 90 percent of all people with normal immune systems will have a immune response to standard dosing. For those people not responding to the standard dose, a series of three 40mcg doses (again, at month 0, month 1 and month 6) can be given. There is data that shows that for some people living with HIV, these double doses can trigger the immune response necessary to protect them from hepatitis b in the future.
What the Studies Show
- A study done at the University Medical School of Sao Paulo showed that double-dosing did trigger an immune response in a greater percentage of HIV infected people than did conventional dosing. However, the double dose made a difference in immune response primarily in people with CD4 counts above 350. Those with CD4 counts less than 350 did not show an appreciable difference between standard and double dosing. Interestingly, having a HIV viral load less than 10,000 also seemed to help the immune response when using the double dose.
- Another study, this of people with weakened immune systems as a result of chronic liver disease showed a favorable response to hepatitis b double-dosing without any side effects or adverse reactions to the additional vaccine.
Ask Your Doctor About Double Dose Hepatitis B Vaccine
If you have had the hepatitis b vaccine series, ask your doctor if your body responded and if you are protected against the virus. The doctor can determine this by a simple blood test that looks for hepatitis b antibodies in your blood. If antibodies are present then you responded to the vaccine and you are protected. If your doctor finds out you have not responded, ask him or her about the double dose hepatitis b vaccine. Depending on your CD4 count, it may be an option for you and an opportunity to get the protection you need.