Breakthrough HIV vaccine shows success in phase 1 clinical trial in humans

Researchers report positive results from a Phase 1 clinical trial of a human immunodeficiency virus (HIV) vaccine. The pathogen usually does not produce an immune response large enough to stop it, which has made it a dangerous and deadly virus. One of the goals of creating a vaccine is to find a formula that would induce the so-called broadly neutralizing antibodies (bnAb), an immune response capable of meeting the challenge. And the trial shows that this vaccine can induce bnAb precursors.

The results are fascinating. These bnAbs rarely grow during infection; in particular, bnAb precursor B cells are rare in humans. But creating such an immune response would prompt the body to fight off infections from various strains of HIV around the world. And this approach could be used not only for HIV, but also for influenza, the hepatitis C virus and betacoronaviruses.

In this phase 1 trial, participants received either two doses of placebo, two doses of the vaccine, or a low-dose version or a high-dose version. These were given 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 germline targeting. There are a small number of B cells in the human body in their “naïve” or “germinal” state. If they encounter a pathogen, these cells will weakly bind to it, and over the weeks they will produce antibodies that are better and better able to attach themselves completely 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.

Although the results are very promising, this is not a simple step towards a full 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 across 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 medications people can live long, healthy lives. And if the viral load falls below the detection threshold, it is impossible for the virus to be transmitted. This is defined by the slogan U=U, undetectable equals untransmittable.

And although vaccines are still a thing of the future, there is currently a drug called PrEP (pre-exposure prophylaxis), which effectively reduces the risk of infection by 99%. While great strides have been made in understanding and fighting this disease, access to life-saving medicines and educational materials about it remains staggeringly unequal, with the most marginalized and at-risk communities receiving the least. Stigma, poverty, education, access to health care, racism, homophobia and transphobia are the main reasons why individuals cannot get the help they need.

There has also been a distinct lack of public and government-sponsored campaigns aimed at informing and de-stigmatizing the infection, and too often politicians and religious leaders have contributed to the spread of ignorance and misunderstanding in both HIV and AIDS.

We can’t all help find a vaccine or a cure for HIV infections, but fighting the stigma surrounding the virus and demanding that our elected leaders provide equitable access to lifesaving medicines is something we can all do.

The results were published in the journal Science.

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