why it so hard to make an hiv vaccine

Vaccines have worked well against once widespread diseases like smallpox and polio. After the AIDS virus was found, many people, including many scientists, thought AIDS would be added to the list. Vaccines mimic natural infections, during which the body produces antibodies that kill the virus. But unlike smallpox or polio, HIV doesn’t stimulate this kind of response – our immune systems are generally blind to the virus and unable to launch an effective antibody attack. Other challenges that scientists face as they try to create a vaccine include a lack of good animal models to study and the virus’s ability to constantly change and mutate. Additionally, although controllers can keep levels of the virus low, no one has ever fully recovered from HIV infection. This means there’s no natural, winning strategy for scientists to study and try to elicit.

Results from previous efforts to build a vaccine have been disappointing. Last year, an HIV vaccine trial in Thailand produced unimpressive results – by some measures, the vaccine reduced the chances of infection by 30 percent at most.

But this summer, scientists discovered three powerful antibodies against HIV and efforts are now underway to transform this discovery into treatment.

In addition to approaches that try to stimulate antibody immunity, researchers are also looking for ways to stimulate cellular immunity, or activate the other weapons in the immune system’s arsenal, like macrophages, natural killer cells, T cells, and more. Alerting the body’s immune system to HIV’s invasion may not prevent infection, but it could inhibit the disease’s progression and keep viral populations so low that there might be less risk of transmission.