The next generation of potential vaccines for HIV are set to be tested in humans. This week, the U.S. National Institutes of Health launched an early clinical trial that will track the safety of three experimental HIV vaccines, all being developed by Moderna and based on its mRNA technology, the same platform used for its FDA-approved covid-19 vaccine.
mRNA is a vital part of how our cells function. It contains the genetic instructions needed for cells to produce proteins. Normally, this mRNA is carried over from the cell’s DNA, but mRNA vaccines deliver their own packet of instructions to cells. In the case of covid-19, the vaccines tell our cells to produce the spike protein of the SARS-CoV-2 coronavirus, a key part of the virus that allows it to infect cells. The spike protein alone can’t cause an infection, but it’s enough to trigger the immune system into action and train our body to better fend off the virus if it ever shows up.
The same principle underlies the three HIV vaccine candidates now being tested by the NIH. They’re all designed to have the body’s cells produce the spike protein of HIV, though they’re encoding slightly different but closely related proteins. Moderna is developing the shots in collaboration with scientists at the Scripps Consortium for HIV/AIDS Vaccine Development at the Scripps Research Institute and the Bill & Melinda Gates Foundation-funded IAVI Neutralizing Antibody Center at Scripps. (This is the only latest foray into HIV vaccine research by Moderna; last summer, it launched a Phase I trial of a different candidate.)
“Finding an HIV vaccine has proven to be a daunting scientific challenge,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, in a statement on Monday. “With the success of safe and highly effective COVID-19 vaccines, we have an exciting opportunity to learn whether mRNA technology can achieve similar results against HIV infection.”
The trial will involve up to 108 healthy adults between ages of 18 and 55 at 11 research sites across the U.S. It will be divided in two groups, with the first group being evaluated two weeks after the first shot to ensure the safety of the vaccines, before the second group is vaccinated with a higher dose version. Should everything go as planned, the volunteers will receive three shots, with the second and third doses taken two months and six months after the first. The trial is expected to conclude by July 2023.
Phase I trials are primarily intended to test the safety of a new drug or vaccine. But the trial will also collect data on people’s immune responses, which should provide the first clues as to whether this approach really can work as hoped.