There have been some big breakthroughs in HIV recently. These include advances showing that HIV infected people who take antiviral drugs are far less infectious and pre-exposure pills that can keep those who don’t have the virus from becoming infected. But these advances don't diminish the need for an HIV vaccine. However, because HIV mutates and changes constantly it has been extremely challenging to create a vaccine that creates an immune response that works against HIV. Additionally, because of HIV variability, there are many different versions of it throughout the world. So a vaccine that works against HIV in Asia may not work against one in Africa or America. Fortunately the level of provided protection that determines what is a successful HIV vaccine is probably lower now. With prevention tools like those mentioned above now available, a less effective vaccine - say one that protects 70% of those vaccinated as opposed to 98% - may now be acceptable. With the moving of that vaccine goal-line it will be easier to score that big touchdown of a working HIV vaccine.

The first big breakthrough in HIV vaccine research was the 2009 RV 144 study that was done in Thailand. Overall, the vaccine was effective for 31% who took it (the vaccine was actually 60% protective the first year, but people in the study were probably challenged with fewer HIV exposures at that point). Researchers now know the vaccine worked well for those whose immune response produced a certain IgG antibody (for those who produced a certain type of IgA antibody the vaccine did not work). Research has confirmed that antibodies in many of those vaccinated were able to target what now is known as a vulnerable part of HIV's outer envelope. Studies will soon be taking place that will attempt to take further advantage of these new found vulnerabilities. And booster shots will also be tried to see if they can improve vaccine efficacy.

Broadly Neutralizing Antibodies (bNAbs) are hot stuff

One type of HIV vaccine that may work is one that induces the production of broadly neutralizing antibodies (bNAbs). They are called that because unlike most HIV antibodies the body produces after being infected with the virus, bNAbs can successfully kill HIV. In fact, they can kill a wide range of types of HIV all over the world, hence the term broadly neutralizing. bNAbs were a hot topic at the recent AIDS Vaccine Conference. Researchers are now seeking a vaccine that creates and immune response that produces these broadly neutralizing antibodies. What's also extremely exciting is that bNAbs work in treating HIV. In fact, clinical studies now show that their antiviral effect lasts so long they only need to be administered about once a month. And because these bNAbs are human antibodies they are virtually non-toxic. Once the kinks have been worked out on how to scale them up through pharmaceutical production, bNAbs may replace more toxic antivirals pills as the standard treatment for HIV infection. Meanwhile, studies have been showing that newer, second generation bNAbs are working even better in stopping the virus.

So is there a way for a vaccine to make people produce their own HIV broadly neutralizing antibodies? Well, an important study just published in Nature Medicine revealed an HIV vulnerability that enables the body to mount a bNAb response which stops the virus. African researchers discovered the HIV mutation by monitoring immune changes in the blood of two infected South African women. There they found that when HIV changed the sugar molecules on its outer surface a certain way, the women started producing bNAbs that could kill 88% of all types HIV. Because HIV mutates so quickly, the body does not make these antibodies long enough to protect those already infected. However, knowing now the specific viral mutation that leads to the production of these miracle antibodies could be the breakthrough needed for creating an HIV vaccine that works.