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Groundbreaking HIV Vaccine Shows Success In Phase 1 Clinical Trial In Humans

These results are a step forward in finding a vaccine against HIV and many other pathogens.


Dr. Alfredo Carpineti


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

Alfredo (he/him) has a PhD in Astrophysics on galaxy evolution and a Master's in Quantum Fields and Fundamental Forces.

Senior Staff Writer & Space Correspondent

Artist impression of HIV being attack and destroyed by antibodies.

The results give hope for better vaccine development strategies. Image credit: Kateryna Kon/

Researchers report the positive results from a Phase 1 clinical trial focused on a vaccine against the Human Immunodeficiency Virus (HIV). The pathogen does not usually produce an immune response large enough to stop it, which has made it a dangerous and deadly virus. One of the goals in the creation of a vaccine is to find a formula that would indue the so-called broadly neutralizing antibodies (bnAb), an immune response that can step up to the challenge. And the trial shows that this vaccine can induce the bnAb precursors.

The results are fascinating. These bnAbs rarely develop during infection; in particular, bnAb-precursors B cells are uncommon in humans. But creating such an immune response would prime the body to fight infections from the globally diverse strains of HIV. And this approach could be used not just for HIV but for influenza, the hepatitis C virus, and betacoronaviruses.


In this Phase 1 trial, the participants received either two doses of placebo or two doses of the vaccine, either a low-dose version or a high-dose. These were administrated eight weeks apart. The vaccine had a favorable safety profile and it induced the right response in 35 out of the 36 recipients of the vaccine.  

The approach is known as germline targeting. There are a small number of B cells in the human body in their “naïve” or "germline" state. If they encounter a pathogen, these cells will weakly bind to it, and over the course of weeks, they will produce better and better antibodies that can fully attach themselves to the virus surface and neutralize it.

The vaccine aims to stimulate these B cells to produce bnAbs. Previous attempts might have not been successful because they did not stimulate enough B cells. 

While the results are very promising, it is not a straightforward step to a full vaccine against HIV. But the methods show an incredible level of control over the responses and could herald a new era of precision vaccine designs. And not just for HIV.


The development of such a vaccine, especially if distributed equitably across the world, would be revolutionary. Currently, 38.4 million people are estimated to be living with HIV, two-thirds of them in Africa. There is no cure for the infection but given the proper medication, people can live long and healthy lives. And if the viral load falls below the detection level, it is impossible for the virus to be passed on. This is defined by the slogan U=U, undetectable equals untransmittable.

And while vaccines are still a thing of the future, there is a drug called PrEP (pre-exposure prophylaxis) currently available, which effectively reduces the chance of infection by 99 percent. While great strides have been made in understanding and fighting this disease, access to life-saving drugs and to educational material about it remains incredibly unequal, with the most marginalized and at-risk communities receiving the least. Stigma, poverty, education, access to healthcare, racism, homophobia, and transphobia are the main reasons why individuals can’t get the help they need.

There has also been a distinct lack of public and government-sponsored campaigns aimed to inform and destigmatize the infection, and too often politicians and religious leaders have contributed to the spread of ignorance and misunderstanding about 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 our elected leaders provide equitable access to life-saving drugs is something we can all do.


The results were published in the journal Science


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  • medicine,

  • hiv,

  • vaccines,

  • antibodies,

  • broadly neutralizing antibody,

  • HIV vaccine