In 1985, researchers believed that an HIV vaccine would soon be developed. IT was speculated that like other viruses, particles of the virus could be used in animals to create antibodies that could be used in a vaccine to stop AIDS. HIV turned out to be trickier than originally thought. While we have made great strides in vaccine research since then, it is possible we may never see an HIV vaccine. That doesn’t mean that we cannot stop or even eliminate AIDS. Even without an HIV vaccine, prevention, HIV testing and treatment can help eliminate the virus.
What exactly is a vaccine?
A vaccine is a preparation that stimulates the body to prevent or eliminate disease. Perhaps the most famous vaccine was the polio vaccine developed by Jonas Salk in 1952 which has since helped end the polio pandemic in the developed world. Hopefully, we will see an HIV vaccine that can do the same for HIV/AIDS. However, numerous challenges still exist in creating an AIDS vaccine.
Types of HIV/AIDS Vaccines in development
Billions of dollars have been invested into the development of a vaccine for HIV/AIDS. A global effort with cross collaboration exists today towards that goal. Two types of vaccines are in development, preventive HIV vaccines and therapeutic HIV vaccines.
Preventive HIV vaccines:
- Aim to prevent HIV from infecting HIV-negative individuals
- Ideally, the hope is these vaccines could be given to everyone–like the polio vaccine, making transmission virtually impossible
Therapeutic HIV vaccines
- Boost the immune systems of HIV-positive individuals OR
- Slow HIV inside the body (like drugs)
Classic science of vaccines
The basic science of creating a vaccine is getting the body to make antibodies using proteins from a virus. When the HIV virus’ DNA was discovered, there was great excitement. Scientists took proteins from the viral envelope and were hopeful that these proteins would stimulate antibody production cutting off the HIV epidemic.
Broadly neutralizing antibodies
Broadly neutralizing antibodies, which can attack multiple variations of HIV, are believed to be central to the creation of an HIV vaccine. While the body does make antibodies to HIV, they are ineffective against the rapidly-mutating nature of the virus. The fundamental question is why doesn’t the body have normal production of these broadly neutralizing antibodies and how can we make this happen.
HIV is different than other viruses
The body usually eradicates viruses naturally. After getting rid of a virus, the body will generate a “police force”–if you will, of antibodies ready to protect at first site of that same virus again. For example, after getting infected with chicken pox, you are unlikely to get it again. Since your body can do this naturally, a vaccines are developed to induce your body to do the same.
In the case of HIV though, the body cannot elicit an effective protective immune response. Instead, the antibodies are made that are often inadequate. The broadly neutralizing antibodies that are needed to fight off the virus are rare. Therefore, in HIV vaccine development, the goal is to get the body to do something that it can’t even do on its own!
Why is HIV different
- HIV rapidly mutates; much faster than other viruses
- It shields itself from antibodies through these mutations
- Many different types exist
- The body cannot get rid of it naturally
- Rarely can the body create effective antibodies
Failure and finally some success with AIDS vaccines
Vaccine development has been ongoing since the discovery of the HIV Virus. Initial vaccines created antibodies against HIV. But by the time they were tested, the HIV virus had transformed due to its rapid mutation rate. The antibodies generated from one type of HIV, didn’t work on other, more prevalent strains. The next phase of vaccine development was creating immune stimulators meant to boost the body’s T-cells, cells that play a major role in helping fight the disease. The Merck vaccine STEP trial was a highly anticipated clinical trial of T-cell stimulating vaccines. However, in 2007, the STEP trial was terminated earlier than planned. In reality, the STEP trials failure was considered to be a major setback in vaccine development. Not only did the vaccine fail to protect against infection, it also failed to raise T-cell levels in patients.
In 2009, researchers were once again enthusiastic with some encouraging news being reported on the vaccine front. It was reported that the RV144 trial (aka the Thai Trial) was able to induce an immune response in people. Even better, there was a 31% reduction in infection rates in patients who had received the vaccine. While its effect was not significant enough to be used as a vaccine, the Thai Trial provided proof that a vaccine was possible, and could be used to reduce transmission of the virus.
To this day healthcare professionals have not given up hope for an HIV vaccine. There is currently a trial study being conducted in South Africa and other academic pursuits of a vaccine/cure.
We now know what we need for an HIV Vaccine
Today researchers have a better understanding of challenges that need to be solved to get an AIDS vaccine. They know what has been wrong with prior vaccines. They also know what went right. The Thai trial provided clues as to how broadly neutralizing antibodies could protect patients. Now researchers feel that they know what they need to do. They just have to focus their energy on how to get it done.
What if we never get a vaccine?
Learn how HIV testing plays a key role in ending the HIV epidemic
Technology can be leveraged to help implement change and stop disease
Proven prevention being implemented to halt spread of the virus