researchers have Discovered the HI-Virus (HIV) almost 40 years ago. Since then, the same question arises again and again: Why is there still no vaccine? The simplified answer: Because HIV is the chameleon of the virus and will be able to change again and again.
to pack Heavy
The HI-Virus to deal with, among other things, so difficult, because it has a complicated, three-dimensional surface structure. In addition, half of this surface is covered with sugar, scientists say – glykolisiert. In such glycol-polymerized surfaces, the immune system can attack bad. And also a vaccine fails in this frosting.
HIV is different
The vaccine research would probably be quite a number of steps, when the HI-Virus would behave like many other viruses. But this is not the case. It changed the form of his cover of the virus from one Generation to the next extremely quickly. to be able to
in order To fight it, depend the immune system of the opponent to recognize. The Virus is changing however, not not the immune system recognises it, sees it as a pathogen and attacks it. So the HI-Virus deceives constantly the immune system and seems to be the research to always be a step ahead.
retroviruses
The HI Virus belongs to the group of retroviruses. You have the ability, their DNA into the host cell to incorporate. Researchers are trying to understand for a long time, how retroviruses reproduce, to be able to strategies to develop a cure. Again and again there are studies, again and again, there are new disappointments, because the Virus is apparently not easy to get a grip on to.
One step forward, two back?
HVTN 702 was a large-scale vaccine trial, which began in 2016 in South Africa. 5407 HIV-negative persons between the ages of 18 and 35 years took part. In the study, a so-called “Prime-Boost was taken”scheme. Two vaccines are combined. The first vaccination – the “Prime”vaccination – has a different active ingredient than the subsequent “booster”vaccination. Behind it is the hope of a wider response from the immune system put this with a vaccine of the case.
the basis for the HVTN 702 trial of the vaccine RV 144 is. It is the only one who could show in a study in Thailand, a rather low protective effect of 31%. The protective effect was maintained, however, only a few months. 129 HIV infections had occurred among the vaccinated subjects and subjects, 124 among those who had received a Placebo.
In February 2020, the South African HVTN 702 has been cancelled-study, however, there is no clear success was visible.
The MOSAICO-vaccine experiment, a further study, which is based on the Prime-Boost scheme. Also here applies that The first vaccination, which runs under the concept Prime, consists of a different active ingredient than the Boost vaccine. In this vaccine, a Protein is included, the copies of the complex HIV-interface. Experiments with monkeys have already run and have shown promising results. By almost 90 percent, could be reduced by using this vaccine combination, the likelihood of Transmission of the HI Virus. Since the end of last year, clinical trials are underway in the United States. 3800 people take part in it.
The third notable study is being conducted under the name IMBOKODO. It, too, belongs in the category of Prime-Boost strategies with 2600 participants from various African countries. So far, the protective effect is hopeful of 67 percent. The study began in November of 2017 and will run until February 2022.
The result of
is one of The great breakthrough is still to wait. In a researchers agree that Even if one of the approaches to HIV vaccination is successful, you will be able to in the near future no 100-percent protection, expected. But a vaccine with a protective effect of 60 to 70 percent would be a success. Until then, there is only the possibility to treat the disease with anti-retroviral drugs.
author: Gudrun Heise
*The contribution of “No vaccine against HIV in perspective” published by Deutsche Welle. Contact with the executives here.
Deutsche Welle
