Wed. Dec 6th, 2023


As the current coronavirus pandemic has shown, new mutations in viral genetic sequences can have a significant impact on the transmissibility of the virus and the damage it causes. For many years it has been feared that this could happen in the HIV-1 virus, which already affects 38 million people worldwide and has caused 33 million deaths to date, and now this new study has just confirmed it.

Researchers have discovered a new strain of HIV that is highly virulent and more harmful to health in the Netherlands, according to a study led by researchers at the Big Data Institute of the University of Oxford, in the United Kingdom, and published in the journal 'Science '.

Individuals infected with the new "VB variant" (for virulent B subtype) showed significant differences before antiretroviral treatment compared to individuals infected with other HIV variants.

Thus, individuals with the VB variant had a viral load (the level of virus in the blood) between 3.5 and 5.5 times higher. In addition, the rate of decline in CD4 cells (the hallmark of immune system damage caused by HIV) occurred twice as fast in individuals with the BV variant, putting them at much higher risk of developing AIDS. quickly .

At the same time, individuals with the VB variant also showed a higher risk of transmitting the virus to other people.

The researchers note that it is reassuring that, after starting treatment, individuals with the VB variant had similar immune system recovery and survival as individuals with other HIV variants. However, they stress that since the VB variant causes a more rapid decline in the strength of the immune system, it is critical that individuals are diagnosed early and begin treatment as soon as possible.

Further research to understand the mechanism that makes the VB variant more transmissible and more damaging to the immune system could lead to the discovery of new targets for next-generation antiretroviral drugs. The VB variant is characterized by having many mutations spread throughout the genome, which means that no single genetic cause can be identified at this time.

Lead author Dr Chris Wymant, from the University of Oxford Big Data Institute and Nuffield Department of Medicine, said: "Before this study it was known that the genetics of the HIV virus were relevant to virulence, which which implied that the evolution of a new variant could change its impact on health. The discovery of the VB variant has demonstrated this, providing a rare example of the risk posed by the evolution of viral virulence."

Lead author Professor Christophe Fraser, from the University of Oxford Big Data Institute and Nuffield Department of Medicine, added that the new findings "underline the importance of World Health Organization guidance. so that people at risk of contracting HIV have access to regular tests that allow early diagnosis , followed by immediate treatment.

"This limits the time that HIV can damage a person's immune system and put their health at risk. It also ensures that HIV is suppressed as soon as possible, which prevents transmission to others," he notes.

The VB variant was first identified in 17 HIV-positive people from the BEEHIVE project, an ongoing study collecting samples from across Europe and Uganda. Since 15 of these people came from the Netherlands, the researchers analyzed data from a cohort of more than 6,700 HIV-positive people in that country. A further 92 individuals with the variant were thus identified, coming from all regions of the Netherlands, bringing the total to 109.

By analyzing the patterns of genetic variation between the samples, the researchers estimate that the VB variant first emerged in the late 1980s and 1990s in the Netherlands. It spread more rapidly than other HIV variants during the 2000s, but its spread has slowed since about 2010. The research team believes that the VB variant emerged despite widespread treatment in the Netherlands, not because of it. since effective treatment can suppress transmission.

Individuals with the VB variant showed typical characteristics of people living with HIV in the Netherlands, including age, gender and the suspected mode of transmission. This indicates that the increased transmissibility of the BV variant is due to a property of the virus itself, rather than a characteristic of people with the virus.