A Vaccine for HIV? The Complexity of a Revolutionary Solution

Evan Hall ​(he/they)

Vaccines: They are advanced medical technology with simple beginnings. They are also splattered in the headlines of our newsfeed as the COVID-19 pandemic persists. The Pfizer and Moderna COVID-19 (Sars-CoV-2) vaccines are based on new advancements in mRNA immunity and delivery in vaccinology.

Vaccines for centuries have stood up to microscopic enemies in an attempt to preserve our human immune systems. The first vaccine was developed in 1798 against smallpox. It would take until 1979 for the complete eradication of smallpox. Smallpox is classified as a virus that can be eradicated. The dominoes of scientific advancement fell over the next century, and there would be vaccines for some of history’s deadliest foes, including the plague. The CDC recommends 17 vaccines for various infections, but the number of different viruses and vaccines in existence easily surpasses that. 

The complexity of the HIV epidemic harkens back to the late 19th century. However, the story of the virus itself in the US begins in the early 1980s. A couple years after the first cases of an unknown syndrome, named at the time by researchers & the media as Gay Related Immunity Deficiency (GRID), then Auto-Immune Deficiency Syndrome (AIDS), the HIV virus was finally scientifically identified by a French and American scientest. After a dispute between governments, the virus was finally classified as the Human Immunodeficiency Virus (HIV) in 1983. 
The US government was well set to advance clinical trials for an HIV vaccine. In 1987, the first clinical trial for a said vaccine opened at the National Institutes of Health. Over 10 years later, the larger and pivotal Phase-3 clinical trial began, which included 5,400 volunteers. The year was 1998. The optimism was felt globally. At the turn of the 21st century, the HIV Vaccine Trial Network was spearheaded by the US to create a consortium of countries to advance the efforts for a vaccine. 

In 2004, there was less than exciting news from one of the vaccine developers. Both of the VaxGen candidates failed to prove efficacy in their Phase 3 clinical trials. A similar tale of optimism with billions of dollars poured into research and thousands of volunteers involved in clinical trials demonstrated time and time again vaccines that were not efficacious against HIV. Duly noted during this period was the revolutionary prophylactic tool approved by the FDA in 2012 - Pre-exposure Prophylaxis (PrEP). This over the counter medication taken once daily proved to reduce the risk of HIV infection upon exposure. Ongoing trials of new modalities of PrEP along with the generic approval of the drug have made ending the epidemic a more feasible goal.

That is, until news from Moderna in August of this year provided a great deal of interest in terms of an HIV vaccine. Although once unknown to the general population, Moderna has come into the spotlight for its effective mRNA Sars-CoV-2 (COVID-19) vaccine. The pharmaceutical company released a statement recently that outlined a Phase 1 clinical trial to investigate a new mRNA version of an HIV vaccine. The renewed interest in vaccine development for HIV came when previously unknown broadly neutralizing antibodies (bnAbs) were identified in patients living with HIV. This meant the scientific community could target vaccines toward our immune system’s B-Cells. (Click here for a great introduction video discussing our immune system.) There have also been identifications and further clarification of the glycoprotein HIV uses to attach to bnAbs. 
The hope for this version of the HIV vaccine is once again breathing life into hope for a solution to end the HIV epidemic. Even so, there is much room to argue that even with an effective HIV vaccine the epidemic is far from over. On the population level, HIV does not meet the requirements for eradicability. Hence, HIV will remain in nature until proven otherwise. We have seen with the COVID-19 pandemic that vaccine distribution on a global scale has favored wealthier and more developed countries. The HIV epidemic is being fought on several fronts, but the most impacted areas are also those with underfunded and underdeveloped health infrastructures, making even the simplest HIV prevention tool, such as condoms, difficult to distribute. What is more evident is that the medications in the HIV library, including PrEP, which is a derivative of treatment drugs for HIV, are costly and unobtainable. Thus, one must ask, who will foot the bill for the expense?

There could be a delighted sense of hope that the government will step in, similar to how they have for the COVID-19 vaccine rollout. However, one pertinent detail will position HIV far away from COVID-19: HIV is classified as a sexually transmitted infection. There are distinct differences between other STIs and HIV in terms of funding, but for the most part they are captured under the same umbrella. Another STI, for which a vaccine is readily available, is HPV. Human Papillomavirus (HPV) is a cancer precursor that infects millions per year in the US and millions more around the world. One would predict that the introduction of the vaccine back in 2006 would usher in the end to HPV, yet the rates of infection have proven otherwise. The cost of the HPV vaccine out of pocket is $250 and is covered by most insurances, but a co-pay may still present challenges. 

In addition, the HPV vaccine’s two-part series is recommended to be administered for children aged 11-12 years old, before the patient has become sexually active. This can present problems for parent-patient relationships when parents do not condone sexual activities until adulthood or even marriage. Many parents falsely believe that measures which help prevent the spread of STIs, such as the HPV vaccine, will encourage their children to be sexually active. As a result, parents may prevent their kids from getting the HPV vaccine. Because the sexual debut of adolescents falls along a spectrum of 15-19 with some blooming early and others later, their opportunity to get vaccinated against HPV before sexual activity with parental consent may prove challenging. This means that parental consent for an HPV vaccine series stands in the way of obtaining necessary sexual health for adolescents in some cases. I know from personal experience, as a similar situation happened to me. Adolescents could have the option to pay out of pocket for the vaccine, but footing the bill for both the vaccine (2 series) and administration costs seems unlikely. The HIV vaccine may be on the horizon. Nonetheless, logistical questions remain to who will ensure the necessary vulnerable populations will receive the vaccine.
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Beyond the sheer undertaking of administering and distributing an HIV vaccine, there is a shadow of stigma that looms largely over the HIV epidemic. Current sexual education, historical contextualization, and general misconceptions surrounding HIV will need a shift in paradigm; only when we achieve this change in culture can the vaccine be as socially viable as it is medically effective. 
Moderna is taking a risk by investigating a new mRNA vaccine for HIV. The new technology faces several failed clinical trials, and billions of dollars spent in an attempt to end the HIV epidemic. However, what is clear with the announcement of the new HIV vaccine Phase 1 clinical trials, is that the HIV epidemic is long from over. The work on the domestic and global scale will require the same human power if not more to continue the fight against HIV.