Four decades later, where is the HIV vaccine?

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Scanning electromyography of an HIV-infected T cell. Credit: NIAID

During the four decades since the first cases of what would be known as AIDS were documented, scientists have made great strides in treating HIV, transforming what was once a death sentence into a manageable condition.

What we don’t have yet is a vaccine that empowers the human immune system to prevent infection before it takes root.

Here is the current state of some of these efforts, which experts consider the “holy grail” in the fight to eliminate a virus that 38 million people worldwide live with.

Why do we need a vaccine?

There are now more people than ever who have access to medications called antiretroviral therapy or ART, which when taken as prescribed, keep the amount of virus in the body.

This keeps them healthy and unable to transmit HIV to their partners.

Beyond ART, people at high risk for infection can now receive pre-exposure prophylaxis, or PrEP, a pill that is taken daily and reduces the risk of infection by 99%.

“But access to medication is not organized in all parts of the world,” Hanneke Schuitemaker, global head of viral vaccine discovery at Johnson & Johnson’s Janssen Vaccines, told AFP.

Even within rich countries, there are wide socioeconomic and racial disparities in access to these drugs, and vaccines have historically been the most effective tools for eradicating infectious diseases.

J&J is currently conducting two human efficacy trials for its HIV vaccine candidate, and the initial results of one of them may be as early as “the end of this year,” Schuitemaker said. .

Why is it so difficult?

COVID-19 vaccines were developed in record time and have shown remarkable levels of safety and efficacy, helping to reduce case burdens in countries fortunate enough to have wide access.

Many of these traits were developed using technologies that were previously being tested for HIV, why haven’t we made progress yet?

“The human immune system does not self-cure HIV, while what was very clear was that the human immune system was very capable of self-treating COVID-19,” said Larry Corey, lead researcher at HVTN, a global organization that funds the development of the HIV vaccine. AFP.

COVID vaccines work by causing antibodies that bind to the ear’s ear protein and prevent it from becoming infected. .

HIV also has spike-shaped proteins on its surface, which are the target of HIV vaccine development.

But while COVID has dozens of well-known variants circulating around the world, HIV has hundreds or thousands of variants within each infected person, William Schief, a leading immunologist in the development of a virus, told AFP. HIV mRNA vaccine at the Scripps Research Institute.

Because it is a “retrovirus,” it is rapidly incorporated into the DNA of its host. An effective vaccine will have to stop the deadly infection, not just reduce the amount of virus and leave the rest to stay with the person forever.

Where are things now?

Efforts to develop a vaccine have been going on for decades, but so far they have ended in failure.

Last year, a study called Uhambo that was conducted in South Africa and included the only candidate vaccine that has been shown to provide some protection against the virus ended up frustrating.

The J&J vaccine candidate is currently being prosecuted in 2,600 women in sub-Saharan Africa at the Imbokodo trial, which is expected to report results in the coming months.

It is also being tested on approximately 3,800 men who have sex with trans men and people throughout the United States, South America, and Europe in the Mosaic process.

The J&J vaccine uses adenovirus technology similar to its COVID-19 vaccine, meaning a genetically modified cold virus provides genetic loading instructions for the host to develop “mosaic immunogens” —molecules capable of inducing an immune response to a wide variety of HIV strains.

This is done following direct injection of synthetic proteins in subsequent doses.

Another promising approach is to try to generate “broadly neutralizing antibodies” (bnAbs) that bind to areas of the HIV virus that are common in their multiple variants.

International AIDS Vaccine Initiative and Scripps Research recently announced the results of an early-stage trial showing its mRNA , developed with Moderna, stimulated the production of rare immune cells that create bnAbs.

His strategy, Schief explained, is to use a sequence of shots to try to progressively educate B cells that produce antibodies. They also hope to form another type of white blood cell, known as T cells, to kill cells that are still infected despite antibodies.

Efficacy trials are still a long way off, but they rely on mRNA technology, which converts the body’s cells. has shown its value against COVID-19, it can make a difference.


Question: How do the different types of COVID-19 vaccines work?


© 2021 AFP

Citation: Four decades later, where is the HIV vaccine? (2021, June 7), retrieved June 7, 2021 from https://medicalxpress.com/news/2021-06-decades-hiv-vaccine.html

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