What is a vaccine?
A vaccine helps the body learn how to fight infections and control diseases. No major epidemic caused by a virus has ever been stopped without a vaccine. An HIV vaccine would help to prevent a person from becoming infected with HIV, or it may control the disease if they do become infected . Right now, there is no vaccine to prevent HIV, and there is still no cure for AIDS. The vaccines being tested are only being used in research studies.
Even though there still is no HIV vaccine, each new research discovery helps guide future efforts. In 2009, a vaccine tested in Thailand was able to lower the number of new HIV infections by about almost a third. This gives us hope that one day researchers will find a vaccine that is safe and effective for everyone.
What is the difference between a preventive HIV vaccine and a cure for AIDS?
A preventive HIV vaccine would prevent infection in a person who does not already have HIV. A cure for AIDS would remove the virus from the body of a person who is already infected. The long-term goal is to develop a vaccine that protects people around the world from getting infected with HIV. But even a vaccine that protects only some people would still be very helpful. Such a vaccine could decrease the number of people who are infected with HIV, which would reduce the number of people who can pass the virus on to others.
Right now, people infected with HIV can take antiretroviral therapy to help control the virus and prevent it from progressing into full-blown AIDS. This therapy, which involves taking a daily combination of drugs, helps people stay well for a longer time, but it is not a cure. Treatments are complex and costly, and they can sometimes cause serious side effects. They also require people to take pills every day for the rest of their lives.
Can I get HIV from the vaccine?
No. The preventive HIV vaccines tested in people do not use actual HIV, which is how some other vaccines (like the flu vaccine) are made. Instead, preventive HIV vaccines are created using genes or proteins that look like those found in the real virus, but are made in a lab. They do not have all of the working parts of the real HIV virus that are needed to cause infection.The vaccines used in these research studies cannot give people HIV.
Could vaccines help people who are already infected with HIV?
Researchers are also looking to see whether HIV vaccines could help people who are already infected with HIV. Vaccines used in this way are called therapeutic vaccines. If effective, a therapeutic vaccine would teach the body to control HIV infection, so the progression from having HIV infection to having full-blown AIDS would happen much more slowly, or maybe even be stopped. We don't know if a vaccine that is found effective at preventing HIV infection would also be therapeutic . It is possible that different types of vaccines might be needed for HIV prevention and HIV therapy. Researchers are working to develop and test both kinds of vaccines.
Why is it taking so long to create an HIV vaccine?
More than 25 years to develop an HIV vaccine might seem like a long time, but most vaccines we use today took at least 30 years to develop.
HIV is a tricky virus. It can "hide" from the immune system that protects the body. Also, there are many different types of HIV found around the world, and the virus changes rapidly, even within a single infected person. Because of this, researchers are working to create vaccines that target the parts of the virus that are more common and that are the least likely to change over time..