Medicine: Promising HIV vaccine does not protect

Promising HIV vaccine does not protect

A logo of the US pharmaceutical and consumer goods manufacturer Johnson & Johnson on a first aid kit.  Photo: Steven

A logo of the US pharmaceutical and consumer goods manufacturer Johnson & Johnson on a first aid kit. photo

© Steven Senne/AP/dpa

There is still no vaccine against HIV. Very special hopes were placed on one candidate. But even those were apparently not fulfilled.

A particularly promising vaccine candidate against the immune deficiency disease AIDS does not provide adequate protection against one HIV-Infection. This was announced by the US pharmaceutical company Johnson & Johnson after reviewing data from the crucial clinical study. “We are disappointed with this result,” said lead researcher Penny Heaton, according to a statement. The phase III study (“Mosaico”) with 3900 subjects will be completed.

According to HIV expert Hendrik Streeck, who was involved in the study on the sidelines, no other preparation had had such good prospects. The poor results of the study that have now been published would have made the search for a vaccine “Clearly thrown back,” said Streeck, who heads the Institute for Virology at the University of Bonn, the German Press Agency. “Until recently I was still hoping that this vaccine might work.” This is how monkeys would have shown their very good immune response against the virus. However, a study (“Imbokodo”) for a similar HIV vaccine had already been stopped in 2021, which also dampened expectations of the “Mosaico” study.

Vector-based vaccine

The vaccine, the study of which is now being completed, is a so-called vector-based vaccine. A weakened cold virus is modified in such a way that it has a blueprint for the virus into cells so that the immune system produces antibodies against HIV. In addition, the immune system is stimulated by the surface protein of the HI virus. A total of four vaccine doses are necessary.

The fight against Immunodeficiency disease AIDS is one of the greatest medical challenges globally. Most recently, around 1.5 million people contracted HIV every year. If an infection is not treated, the virus weakens the immune system to such an extent that life-threatening illnesses occur. One then speaks of AIDS (Acquired Immune Deficiency Syndrome).

There are now drugs that protect against infection (PrEP) for people with an increased risk of infection. Daily intake is recommended. There are also medicines that inhibit the multiplication of the virus in infected people, so that the disease AIDS does not break out.

So far, however, there is no vaccine because the virus poses special challenges for researchers. The HI virus comes in many different variants and changes comparatively quickly, explained Streeck. This makes it difficult to develop a vaccine that protects across the board. In addition, the virus has a special surface on which immune substances stimulated by the vaccine can attack with comparative difficulty.

Another challenge is that a vaccine would have to lead to the generation of a completely protective, i.e. sterile, immunity. A short-term or slight infection despite vaccination is not possible because the virus attacks the immune system directly.


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