New HIV Vaccine, Based on COVID-19 Vaccine Research, Heads for Trials

Moderna is set to begin Phase I trials of two promising vaccines against HIV, using technology it developed in its successful efforts to create a vaccine against COVID-19, Popular Science reported.

The publication referenced "a new posting in the National Institutes of Health's clinical trial registry".

The new vaccines are "based on the same mRNA platform behind its successful covid-19 vaccine," Gizmodo explains. "The trial will test the vaccine's safety and measure the relevant immune response generated in a small group of healthy volunteers."

A chief reason HIV has confounded efforts to engineer effective vaccines is that the virus "quickly mutate parts of its structure, making it hard for HIV-specific antibodies produced by the immune system (elicited either through infection or a theoretical vaccine) to recognize it," Popular Science clarified.

"For decades, though, we've known that some people can produce broadly neutralizing antibodies to HIV – antibodies that can target multiple strains of the virus. These antibodies focus on stable parts of the virus that don't change much as it mutates, allowing them to remain potent."

Many past attempts to create a vaccine have been predicated on "coaxing the immune system to produce these broadly neutralizing antibodies on its own, much as some genetically blessed people can do already."

That's the approach that Moderna has taken in its new vaccine. Popular Science related that "mRNA strands in the vaccine enter human cells, providing them with the code to make little bits of the same proteins that sit on the virus's exterior. Those proteins then act like test dummies for our immune systems to recognize, so immune cells in the future can identify and neutralize the actual virus.

"The process works incredibly well against SARS-CoV-2, and there's hope that it may work with HIV as well."

Hopes for an effective HIV vaccine rooted in COVID vaccine research were at the root of headlines earlier this year when Scripps Research announced its own plans to follow that line of scientific inquiry.

National Geographic pointed out at the time that existing "clinical, laboratory, and biostatistical infrastructure created by the HIV Vaccine Trials Network" were instrumental in propelling a rapid COVID-19 vaccine to fruition, and noted that COVID vaccine efforts could rebound in turn to benefit HIV vaccine efforts.

Scripps Research's effort showed promise, Popular Science recalled, "with 97 percent of participants developing some kind of immune response (though not the full responses that would be required to fend off HIV infection)."

The article added: "By leveraging Moderna's mRNA system, researchers are aiming to improve and broaden the kind of cells and antibodies that the body produces in response to the vaccine."

But a new vaccine against HIV might not be as quickly available as the vaccines now being used against COVID-19. Phase I trials are just the start of a meticulous vetting process, and years of development and testing could lie ahead.

Gizmodo gave some indication of the likely time scale, pointing out that "Moderna's current Phase I study isn't expected to finish until 2023, and prior to the covid-19 vaccines, the shortest gap between human trials and full approval for a vaccine was five years."

So why was a COVID vaccine possible in such a short period of time, whereas any HIV vaccine is almost certainly years away?

"During the COVID-19 vaccine trials, the coronavirus was spreading widely around the world, allowing faster data gathering for how well the shot protected people," Gizmodo explained. "HIV is much less common, so gathering the needed data to confirm a vaccine works will take longer."