Researchers reported positive results from a Phase 1 clinical trial focused on a Human Immunodeficiency Virus (HIV) vaccine.
The pathogen does not usually produce a large enough immune response to stop it, which has made it a dangerous and deadly virus.
One of the goals in creating a vaccine is to find a formula that induces so-called broadly neutralizing antibodies (bnAbs), an immune response that can rise to the challenge.
The trial, the results of which were published in the journal Science, show that this vaccine can induce bnAb precursors.
These bnAbs rarely develop during infection; in particular, bnAb precursor B cells are rare in humans. But creating such an immune response would prepare the body to fight infections from the various strains of HIV around the world .
This approach could be used not only for HIV, but also for influenza, hepatitis C virus, and betacoronaviruses.
In this Phase 1 trial, participants received either two doses of placebo or two doses of the vaccine, either a low-dose version or a high-dose version. These were administered eight weeks apart. The vaccine had a favorable safety profile and induced the correct response in 35 of 36 vaccine recipients.
The approach is known as germ line selection. There are a small number of B cells in the human body in their “naïve” or “germ” state. If they encounter a pathogen, these cells will loosely bind to it and, over the course of weeks, produce better and better antibodies that can fully adhere to the surface of the virus and neutralize it.
The vaccine aims to stimulate these B cells to produce bnAbs. Previous attempts may not have been successful because they did not stimulate enough B cells.
While the results are very promising, it is not an easy step toward a complete HIV vaccine. But the methods show an incredible level of control over responses and could herald a new era of precision vaccine design. And not just for HIV.
The development of such a vaccine, especially if distributed equitably around the world, would be revolutionary. Currently, an estimated 38.4 million people are living with HIV, two-thirds of them in Africa.
There is no cure for the infection, but with the right medication, people can live long and healthy lives. If the viral load falls below the detection level, it is impossible for the virus to be transmitted. This is defined by the motto “undetectable equals untransmittable”.