illustration of the HIV virus, which already affects more than 38 million people worldwide.
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As the current pandemic from covid-19, 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 with the HIV, present in more than 38 million people worldwide and has caused 33 million deaths to date. (You can read more health news here)
Fears seem to be confirmed now with the discovery of a new strain with greater infectivity in more than 100 people of the Netherlands, according to a study led by researchers at the Big Data Institute at the University of Oxford (UK). The results were published last week in Science.
Individuals infected with the new V-B variant (by virulent subtype B) showed significant differences before antiretroviral treatment compared to those infected with other variants: those with BV had a viral load between 3.5 and 5.5 times higher.
Furthermore, the rate of decline of the CD4 T lymphocytes – the hallmark of immune system damage caused by HIV – occurred twice as fast in individuals with the BV variant, putting them at risk of developing AIDS much more quickly. Likewise, they also showed an increased risk of transmitting the virus to other people.
“This new VB variant has greater virulence, that is, it has a more detrimental impact on health than is normal for HIV,” Chris Wymant, lead author from the University of Oxford, explains to SINC. (You may be interested: Quarantines disrupted our nutrition)
“The study shows how a virus that has been circulating among humans for more than a century can continue to adapt, evolve and become more virulent,” says Joel Wertheim, a professor at the University of California at San Diego (USA) and author of an article. that accompanies the investigation.
However, it is reassuring that, after starting treatment, individuals with the VB variant had a recovery of the immune system and survival similar to those of individuals with other HIV variants.
However, the scientists stress that since the VB variant causes a more rapid decline in the ability of the immune system, it is essential that affected people are diagnosed early and start treatment as soon as possible. (You may be interested: The countries that would not meet the WHO anticovid-19 vaccination goal)
“This demonstrates the importance of timely provision of HIV treatment to all those who receive it. diagnosis. First-line drugs should work just as well against this variant to prevent disease and further transmission,” adds Wertheim.
Know how virulence evolves
Tracking the virulence of HIV is a key task. However, outside of recent studies on SARS-CoV-2 variants, knowledge on the evolution of virulence in viruses beyond theoretical analyzes is lacking. 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.
“Before this study it was known that the genetics of the HIV virus were relevant to virulence, which implied that a new variant could change its impact on health. This discovery has shown it, with a rare example of the risk posed by the evolution of viral virulence, “says Wymant.
Christophe Fraser, another of the British institution’s experts and author, underlines the importance of the guidelines of the World Health Organization (WHO) so that people at risk of contracting HIV have access to periodic tests that allow an 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 the virus is suppressed as soon as possible, which prevents transmission to other people,” he notes, “and these principles apply equally to the VB variant.”
Thus, the team believes that this variant arose despite widespread treatment in the Netherlands, not because of it, as effective treatment can suppress transmission.
This is not a public health crisis
Although the researchers have described many different properties of this new variant, they do not explain the mechanism by which it is more virulent. “We don’t have experience in cell biology, so now we pass the baton to people who can study the interaction of this virus with cells of the immune system under controlled experimental conditions,” explains Wymant.
According to Joel Wertheim, when these individuals were diagnosed they were vulnerable to developing AIDS within 2-3 years: “Subsequent analysis of the VB variant showed significant genome-wide changes affecting nearly 300 amino acidsmaking it difficult to understand why this particular variant is so virulent.”
However, he wants to make it clear that observing the appearance of a more virulent and transmissible HIV it is not a public health crisis: “Let’s not forget the exaggerated reaction that the ‘super-AIDS’ claim entailed in 2005, when the alarm was triggered by a rapidly progressing multi-resistant HIV infection detected in New York, which was finally limited to a single individual”, he clarifies.
Future research to understand the mechanism that makes the VB variant more transmissible and more damaging to the immune system could uncover new targets for antiretroviral drugs new generation. “Society should not worry. This finding underlines the importance of the guidelines that were already in force: early diagnosis and immediate treatment”, conclude the experts.
How the new variant was located
It all started with the BEEHIVE (Bridging the Epidemiology and Evolution of HIV in Europe) project, an ongoing study collecting samples from across Europe and Uganda. In it, the VB variant was identified for the first time in 17 seropositive people.
Since 15 of them came from the Netherlands, the researchers analyzed data from a cohort of more than 6,700 HIV-positive citizens of the 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 among the samples, the authors estimate that the VB variant first emerged in this country in the late 1980s and 1990s. And it spread more rapidly than other HIV variants during the 2000s, but its expansion has slowed since about 2010.
Individuals with this variant showed the typical characteristics of people living with HIV in the Netherlands, including age, gender and presumed 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.
The scientists also detected one individual with the variant in Switzerland and another in Belgium, and say there are likely to be at least a few more people elsewhere who have not yet been detected: “By making the genetic sequence of the VB variant public , we allow other specialists to check their own private data”.