Because vaccine development is stalling, drugs are now supposed to end the AIDS pandemic

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Science: World AIDS Day: Current research

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Research is being carried out around the world into ways to cure AIDS. So far this has not been successful and there is no vaccination yet, but there are extremely effective medications.

Even though AIDS cannot be cured, an infection with the human immunodeficiency virus (HIV) can now be treated very efficiently. Antiretroviral drugs have been the treatment of choice for HIV since the mid-1990s. They suppress the virus in the body and prevent it from multiplying. The virus is then no longer transmittable and can be permanently controlled.

Most patients receive a combination of different antiretroviral medications, each targeting different stages of the HIV cycle.

With this therapy, those affected usually take one or two tablets every day. Check-ups that should be carried out every three months are also important. Among other things, the viral load in the body is measured, i.e. how much HIV RNA is in the blood. The lower the viral load, the better.

Building on this, the therapy has continued to improve, says Hendrik Streeck. He is the director of the Institute for Virology at the University Hospital of Bonn and specializes in AIDS research.

The last major breakthrough was the integrase inhibitors, said Streeck. The enzyme integrase plays an important role in the replication of the HIV virus and is responsible for ensuring that the so-called viral DNA genome integrates into the host cell and can multiply there.

“This active ingredient is simply enormously effective,” explains Streeck. “These integrase inhibitors essentially saved the lives of many patients who perhaps already had a very resistant viral infection and for whom there were hardly any active ingredients left. They are now part of every therapy.”

Better medication

One focus of AIDS research is on developing medications that are even more tolerable than previous ones, although side effects now only occur extremely rarely. Research is also underway into how medications can be administered more easily and yet efficiently.

These include, for example, preparations that have a type of depot that then releases the corresponding active ingredient within defined periods of time. Research is also underway on an implant. There are a wide variety of approaches around the world, some of which are already being used in practice, others are still being developed.

“We have more and more good therapies. The big question here is: How do you achieve long-term effectiveness? The near future is an injection that is given once a year so that you no longer have to swallow a tablet every day,” says Streeck.

For those affected, it is certainly another step in the right direction and it also has a psychological effect. Patients are not reminded about the virus every day.

Treatment before and after

The so-called PrEP, pre-exposure prophylaxis, is a precautionary measure. It prevents the HIV viruses from multiplying. A combination drug from HIV therapy is used for this purpose. The active ingredients reach, among other things, the cells of the mucous membranes, which come into contact with body fluids during sex. For PrEP to work, there must be a sufficient amount in the mucous membranes. Once PrEP is stopped, the effect stops.

If you are worried that you may have become infected through sexual intercourse, you have the option of taking HIV medication for four weeks. This post-exposure prophylaxis, PEP, prevents the infection from spreading.

PEP is useful, for example, for women who have been raped, but also for doctors who fear that they have become infected from a patient. Treatment must be carried out as soon as possible, but no later than 48 hours after the suspected infection.

Waiting for the vaccination

Even after 40 years there is still no vaccine. But at least AIDS research has made a significant contribution to the development of corona vaccines. “We wouldn’t have had the corona vaccine so quickly if we hadn’t done all the HIV research beforehand. Many of the concepts that were used were developed in vaccine research,” explains Streeck.

Many would like to see an HIV vaccine developed as quickly as possible and see this as the best solution. But news of success is often followed by disillusionment. This also applies to developments that are already well advanced. Unfortunately, the last vaccine trials were stopped early because they were not effective. Unfortunately, we still don’t understand why we can’t manage to build up sterilizing immunity,” Streeck notes.

There have been eight effectiveness studies in advanced stages for HIV. “Basically all of them failed except for one. We had a vaccine – we call it the Thai trial because it was done in Thailand. It showed 31 percent effectiveness. We have not been able to repeat this effectiveness in any other experiment,” says the AIDS researcher.

Developing an effective vaccine is so difficult because the virus is constantly changing, giving rise to countless forms of HIV. And although some antibodies are certainly capable of fighting one variant of the HIV virus, for example, they are completely ineffective against other forms. Because of these many variants, developing a vaccine is still a difficult undertaking.

The end of the pandemic

In addition to mRNA vaccines, the focus of global AIDS research is also on the CRISPR-Cas9 gene scissors. It could cut HIV genetic material from human DNA or enable the reprogramming of immune cells. Ideally, these reprogrammed immune cells could kill infected cells. Intensive research is also being carried out on antibodies that can recognize different variants of the HIV virus and thus block their replication.

Until these approaches are fully developed, it is important to exploit the existing possibilities. This means that everyone has access to education, tests, prophylaxis and therapies.

Streeck already sees good opportunities in the fight against HIV and AIDS. “HIV patients who receive good treatment can no longer pass on the virus. And we have prophylactic measures that protect against HIV infection. In this way, we could already contain the pandemic worldwide.”

Author: Gudrun Heise

The original for this article “World AIDS Day: State of Research” comes from Deutsche Welle.

Deutsche Welle Science/Environment