HIV Vaccine Awareness Day: We Aren't There Yet, But Are We Close?

Many advancements have been made in the fight against HIV since it was first recognized back in 1981. Now, with the help of antiretroviral therapy, an HIV diagnosis no longer equates to a death sentence—individuals infected with the virus can live longer lives with relatively little side effects.

On May 18, 2017, HIV Vaccine Awareness Day, advocates from all different walks of life reflect on progress made toward reaching a common goal that seems to remain just beyond their reach: developing an HIV vaccine.

One of the key players that has helped individuals fight back against the virus is antiretroviral therapy (ART), which involves individuals adhering to an HIV regimen that consists of a combination of medications. When the regimen is adhered to, it has been proven that this therapy effectively “keeps HIV at undetectable levels,” and thus, reduces the risk of infected individuals passing the virus on to their partners. ART can also be used as a means for prevention, and, according to the National Institutes of Health, “when implemented in communities, treatment as prevention is remarkably successful at preventing the spread” of infection. Another preventive option available for individuals at risk of infection is pre-exposure prophylaxis (PrEP), which reduces the risk of acquiring the virus through sexual intercourse by over 90%—all individuals have to do is remember to take one pill on a daily basis.

These preventive tools have attributed to cutting down the incidence of HIV; however, a vaccine that is both safe and effective would completely change the game. The NIH reports that in just 2015, a staggering 2 million infections occurred worldwide, and there has only been a slight decrease in infection rate since 2010.

However, a study funded by the NIH, found that “a 50% effective preventative vaccine could reduce the number of people living with HIV by 36% globally over a period of 15 years.” In fact, a vaccine combined with “the other medical and behavioral prevention modalities” could significantly lower the number of individuals infected with the virus.

Scientists from all over the world have channeled their efforts into developing a vaccine, but thus far, have not been successful. Why? HIV is known for its constant, rapid mutations. These mutations remain an obstacle for scientists, as well as the immune system, as they often allow the virus to avoid detection. Another challenge has to do with broadly-neutralizing antibodies; these antibodies “can fight an array of HIV strains by binding to key sites on the virus.” The problem is, not many infected individuals develop these antibodies, and those who do often develop them after the virus “has already gained a strong foothold in the body.”

However, all is not lost.

A phase 2b/3 HIV vaccine efficacy trial, called HVTN 702, was launched by the National Institute of Allergy and Infectious Diseases (NIAID) and others in 2016—the first HIV efficacy trial in 7 years. The aim of the study is to test if a vaccine regimen can effectively provide adults with adequate protection against the virus.

Another approach being taken in this space focuses on inciting the immune system to create broadly neutralizing antibodies. Last year, two multinational clinical trials, dubbed the AMP Studies, were launched to test “an investigational anti-HIV broadly neutralizing antibody” for preventing infection with the virus. The goal of these trials? To test how “safe, effective, and tolerable” giving individuals “a broadly neutralizing HIV antibody as an intravenous infusion every 8 weeks” is.

Researchers from the University of Copenhagen Faculty of Health and Medical Sciences have taken their efforts in a different direction in an attempt to reach the same end goal. The researchers developed a strategy that focuses on “boosting the parts of the immune system attacking viral genes, which are the least active during infection.” According to a recent press release, this could work to prolong the “resistance of the immune system to the virus.” The results yielded by their recent study suggest that this strategy might ultimately be used to prevent infection with HIV as well as other infectious diseases.

There are many obstacles that scientists face in this fight, but with each new study, more knowledge is added to the arsenal, which brings scientists that much closer to reaching their long-sought-after goal.