In-Depth: Trials underway for mRNA-based HIV vaccine

Vaccines developed at Scripps Research
Posted at 5:53 AM, Mar 21, 2022
and last updated 2022-03-21 10:10:07-04

SAN DIEGO (KGTV) - Testing will begin soon on three HIV vaccines based on mRNA technology developed in San Diego.

Scripps Research and the International AIDS Vaccine Initiative (IAVI) have been working with Moderna on mRNA technology since 2016. Vaccine Design Director Dr. William Schief says the success of mRNA against COVID-19 helped push the HIV vaccine towards human trials.

"The fact that that COVID vaccine was so immunogenic and so successful at protecting humans made it easier for NIH to say, 'Yes, this is a good idea. Let's go test this for HIV,'" says Dr. Schief.

Last week, the NIH announced the start of human clinical trials for three mRNA HIV vaccines, all using mRNA sequences developed at Scripps Research in La Jolla. Each vaccine delivers the mRNA in a different way.

"One way is a soluble spike protein," explains Dr. Schief. "Another way is the spike protein will be anchored to cell membranes. And a third way is it will be anchored to cell membranes, but it has a mutation that might make it perform better... What we're doing with this clinical trial is asking the question: If we're going to deliver HIV spikes by RNA to humans, what's the best way to do it?"

The trials will also look at different dosage amounts, with some participants getting 100 micrograms of the mRNA, and others getting 250. They hope to see which level creates a sufficient immune response.

Researchers will also track safety and side effects.

The National Institute for Allergy and Infectious Diseases is sponsoring the study. Director Anthony Fauci, who spent the majority of his career pre-COVID working on HIV, told ABC 10News the use of mRNA for COVID sped up the process.

"It's exciting in the sense of its potential," Dr. Fauci says. "Had it not been for the success and utilization in COVID, we very likely would not be looking at this in the context of HIV/AIDS."

But, Dr. Schief says HIV is one of the most complex viruses ever, with "millions" of different spikes that would need to be neutralized for full protection. Because of that, he doesn't expect these trials to produce a vaccine that will offer immunity from the virus. Instead, he believes it will take a series of vaccines. Still, this is an important first step towards that goal.

"It's still, we believe, going to take five to 10 years to discover a full sequence of immunogens that induce the kinds of responses that we're looking for," he says. "(But) even if the responses are low, and it doesn't look like a great vaccine at the starting blocks, I'm just hoping that we can distinguish between the three different ways of delivering the spike."

And since mRNA is a faster, less expensive way of creating vaccines than the traditional protein-based method, it creates endless possibilities.

"You never want to get too excited about something until you've proven it works," says Dr. Fauci. "But at least we know from the experience with COVID that this is a very exciting and potentially important technology."

The trials will run through July 2023.