Researchers are Cautiously Optimistic for a HIV Vaccine

Recent social media posts hail the work of researchers who may finally be closing in on a vaccine against HIV. The excitement centers on a February announcement, from Scripps Research and nonprofit vaccine research organization IAVI, that spoke of "promising blood-test results from the first phase one human trial of a new HIV vaccine strategy," the National Geographic reports.

But pushing past social media hype, the optimism – while grounded in promising science – is cautious, and any broadly effective vaccine is still most likely years away, the article noted.

The road to an effective HIV vaccine has been long and, at times, dispiriting. With their first efforts, in the 1980s, researchers expected that the tried and true approach of identifying naturally-produced antibodies would open the way to a vaccine, the story recalled. HIV, however, constantly mutates and does so quickly enough that it has frustrated such efforts.

Researchers then focused on methods to harness the body's natural defenses, B cells and T cells, to aggressively fight back against HIV. But a trial testing the effectiveness of a T cell-based vaccine not only failed, the National Geographic piece recalled, it "also appeared to increase the risk of HIV infection."

That's when research focused on B cells, the idea being to prompt "naive" B cells to "acquire mutations that transform them into cells that produce broadly neutralizing antibodies before an HIV infection," such that "the body might be able to fight it off when presented with the virus for the first time" – the hallmark of an effective vaccine.

Scripps researcher William Schief (who also leads vaccine design efforts at IAVI) described the approach as "trying to take the driver's seat with the immune system and educate it step by step with a vaccine," the article related.

Recent efforts to produce such B cells using "an engineered protein nanoparticle" designed to "activate these cells and get them to multiply and mutate toward producing" the proper antigens generated promising results: "35 of the 36 people who received the vaccine... produced the intended B cell responses," the article noted.

The development is exciting, but victory is not yet in researchers' grasp. Years of development and testing lie ahead, and HIV has already proven a cunning foe, repeatedly dashing hopes for a vaccine for four decades.

But if the initial promise of the new approach holds true, then at some point in the not-too-distant future, "people might get a succession of shots over weeks to years, beginning with one that starts where the new trial did: interacting with the right naïve B cells, to get the process started," the National Geographic reported. "Subsequent shots would guide the B cells to produce fully mature broadly neutralizing antibodies."

Existing "clinical, laboratory, and biostatistical infrastructure created by the HIV Vaccine Trials Network" were instrumental in propelling a rapid COVID-19 vaccine to fruition, the article pointed out. COVID vaccine efforts could rebound in turn to benefit HIV vaccine efforts if the push for vaccines against the pandemic carries over to "generate new interest in the search for HIV vaccines, which will also require the public's collaboration," the article noted.

The decades-long push to end HIV can only benefit from such momentum. Earlier this year, UNAIDS unveiled a strategy to eradicate AIDS by 2030; President Biden has spoken of a more ambitious goal of ending the decades-long epidemic by 2025 and asked for a funding increase of more than 25% for the Ending the HIV Epidemic initiative in fiscal 2022.