3 Experimental mRNA HIV Vaccines: Hope on the Horizon to Prevent HIV?

Ever since the discovery and identification of HIV in 1983, scientists have gone through the long and winding road when it comes to making advancements in treatments. HIV is an incurable sexual disease which, if left untreated, can lead to AIDS, a debilitating and lifelong health condition that paralyzes a person’s immune system, making seemingly simple infections such as flu can be hard to fight off.  Although scientists have come a long way when it comes to HIV prevention by creating pre- and post-exposure prevention methods like HIV PEP and HIV PrEP, there are still challenges that have yet to be tackled: developing an effective HIV cure and HIV vaccine.

However, hope is on the horizon when it comes to a HIV vaccine because the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health (NIH), has commenced a phase 1 clinical trial assessing three experimental HIV vaccines that utilizes the messenger RNA platform, an approved technology applied in particular COVID-19 vaccines. Funded by NIAID, the study will be conducted by the HIV Vaccine Trials Network (HVTN) at Seattle’s Fred Hutchinson Cancer Research Center. On the other hand, these experimental vaccines will be manufactured in collaboration with Massachusetts-based Moderna, who has been reaping success in preventing COVID-19 by producing mRNA vaccines.

How mRNA HIV vaccines work

The study is called HVTN 302 and will evaluate the safety of three experimental mRNA vaccines, namely the BG505 MD39.3 mRNA, BG505 MD39.3 gp151 mRNA, and BG 505 MD39.3 gp151 CD4KO mRNA. Researchers will also assess if these three vaccines can induce immune responses.

The way an mRNA vaccine works is by sending a piece of genetic material that tells the body to create a protein fragment of a target pathogen (for example, a virus) so that the immune system remembers and recognizes the pathogen in order to mount a response when exposed to that pathogen. The vaccine is designed to induce white blood cells to transform into antibodies that can neutralize HIV. Each of these experimental vaccines is devised to show the spike protein discovered on the surface of HIV that eases entry into human cells. It is important to note that none of the three vaccines can lead to HIV infection. Besides three experimental vaccines, a booster shot is also being studied. This mRNA technology was known to pave the way for the first two licensed COVID-19 vaccines.

Prior to this fresh approach, finding an effective HIV vaccine has proven to be challenging. Stephen Hoge, M.D., president of Moderna, further elaborated that coming up with a vaccine regimen that prompts sustained protective levels of HIV neutralizing antibodies was not easy to attain, but he also believed that mRNA presents an opportunity to weather the challenge. With the launch of this clinical trial, Moderna is taking it up a notch and upping their strategy to use various mRNA encoded native-like HIV trimers and increase the power of their mRNA platform to expedite the invention of a protective HIV vaccine.

Carrying out the mRNA vaccine experiment

Led by Jesse Clark, M.D., an HIV researcher at the University of California, Los Angeles and Sharon Riddler, M.D. of the University of Pittsburgh, the HVTN 302 will gather around 108 adults from the age of 18 to 55 in Birmingham, Alabama, Boston, Los Angeles, New York City, Philadelphia, Pittsburgh, Rochester, New York and Seattle. Every participant will be randomly assigned to one of six groups and receive three doses of one of the experimental vaccines. The first three groups, consisting of 18 participants in each group (called Group A), will be administered intramuscular injections of 100 micrograms of the assigned vaccine candidate during the first visit, at month two and at month six. Two weeks after the initial dose, these participants will be evaluated to make sure that the safety criteria have been fulfilled. If everything goes well, the remaining 54 participants included in Group B will receive 250 micrograms of the experimental vaccine at the same time intervals.

This clinical trial is expected to wrap up by July 2023 and safety and immune responses will be assessed through blood and lymph node fine-needle aspiration samples taken at particular time stamps throughout the trial. Anthony S. Fauci, M.D., Director of NIAID, conveyed his optimism in this study, saying that this would be an opportunity to learn if the mRNA technology can produce the similar results to fight HIV as it does COVID-19.

The immunogens (antigens that induce an immune response) which are currently being tested were created by the International AIDS Vaccine Initiative (IAVI) and Scripps Research.

For the past 4 decades, scientists have been hard at work to come up with breakthroughs to combat HIV. All this time, this virus has been so elusive that it can dodge every attempt made by the immune system to destroy it. To date, according to the Joint United Nations Programme on HIV/AIDS (UNAIDS), as of 2020, there were around 37.7 million people living with HIV in the world. A lot of benefits can be reaped from inventing an effective and safe HIV vaccine, considering how sinister and malicious AIDS can be in impacting a person’s health. Although HIV-positive people can receive antiretroviral treatments to keep the virus at an undetectable load in order to prevent transmission, this requires patients to be aware that they are infected with HIV and they need access to this kind of care.

As technology and medicine progress at a rapid rate, HIV is no longer a death sentence. However, until this clinical trial is proven successful and effective, taking preventative measures such as practicing safer sex (using condoms and other protective barrier methods), going regularly for STD testing and taking HIV PrEP for people who are at a greater risk for HIV are the wisest steps a person can take.

Shim Clinic is a STD clinic in Singapore that provides STD testing, diagnosis and STD treatment. If you feel like you are at a heightened risk for HIV, we carry prevention methods such as HIV PrEP. When consumed as prescribed, HIV PrEP is effective at preventing HIV transmission by about 99%. We also provide HIV PEP that works best when taken within 72 hours after a possible exposure to HIV.