A New, 'Highly Virulent' HIV Variant Was Just Discovered in Europe

 


In the Netherlands, a new form of HIV, the virus that causes AIDS, was discovered, and it appears to promote quicker disease development than existing variants of the virus.

The human immunodeficiency virus (HIV) infects and kills immune cells known as CD4 cells in the body, resulting in a decrease in their quantity. If the infection is not treated, it can lead to AIDS. CD4 levels fell at nearly double the rate in patients infected with the novel HIV variant, known as the VB variant, as they do in people infected with closely related HIV strains, meaning those of the same genetic subtype (B).

Researchers published Thursday (Feb. 3) in the journal Science that infections with the VB variation would likely proceed to AIDS within two to three years of a person's initial HIV diagnosis if they were not treated.

On average, six to seven years after diagnosis, other variants of the virus show a comparable level of decrease.

In an email to Live Science, first author Chris Wymant, a senior researcher in statistical genetics and pathogen dynamics at the University of Oxford, said, "We found that on average, individuals with this variant would progress from diagnosis to 'advanced HIV' in nine months if they do not start treatment and if diagnosed in their thirties." He believes that the condition would grow considerably faster in an older person, he said.

Thankfully, the researchers discovered that antiretroviral medications, which are the conventional therapy for HIV, perform just as effectively against the VB variation as they do against other strains of the virus in their research.

"The degradation of the immune system towards AIDS is stopped for an individual on effective therapy, and transmission of their virus to other individuals is prevented," Wymant added.

How the variant was spotted

Wymant and the study's senior author, infectious-disease researcher Christophe Fraser, are also part of the BEEHIVE project, which aims to better understand HIV biology, evolution, and epidemiology.

"The BEEHIVE study, which began in 2014," Wymant explained, "was established to explore how alterations in the virus's genomes produce disparities in illness." "Data from seven national HIV cohorts in Europe, as well as one in Uganda, are combined in this research."

During the course of reviewing data from the continuing study, the researchers discovered 17 people infected with a "distinct" HIV variety, all of whom had unusually high levels of the virus in their blood early in infection — between six months and two years after diagnosis. There were fifteen infected people from the Netherlands, one from Switzerland, and one from Belgium.

According to the researchers, the new variety belongs to the genetic subtype B, a group of similar HIV viruses that are most typically seen in Europe and the United States. The researchers analyzed data from the ATHENA national observational HIV cohort, a large group of HIV-positive persons in the Netherlands who were diagnosed between 1981 and 2015, to see whether they could uncover further occurrences of the variation in the Netherlands.

More over 8,000 of these people had viral genetic sequence data, and roughly 6,700 of them were infected with subtype B viruses. The researchers found 92 people with the unusual VB variation among this cohort, bringing the total to 109.

These 109 persons had 3.5- to 5.5-fold greater viral loads than people infected with other subtype B strains, according to available clinical data. Individuals infected with the VB variety already had lower CD4 levels than those infected with other strains at the time of diagnosis. As a result, when compared to other HIV-positive patients, their CD4 levels started lower and decreased quicker.

The researchers went back to the VB variant genome in quest of evidence to explain how this significant increase in virulence occurred. They discovered that the variation has several mutations distributed across its genome, thus they are unable to establish a single, isolated genetic explanation for the virus's heightened virulence at this time, according to the researchers.

"It's improbable that a single mutation, or even a single gene, is to blame for this shift," said Joel Wertheim, an associate professor of medicine at the University of California, San Diego, who was not involved in the research. In an email to Live Science, he said, "Working out this process is of considerable interest."

Based on the available genetic data, the team was able to create a phylogenetic tree, which is "quite comparable to conventional family trees for people" and shows how closely various individuals are connected to one another, according to Wymant.

They calculated that the VB variation initially arose in the Netherlands in the late 1980s or early 1990s based on this tree. According to a 2019 analysis published in the journal Health Affairs, the first antiretroviral therapy for HIV had just been licensed by the US Food and Drug Administration at the time, and regimens combining antiretrovirals were not yet accessible.

"There would have been a substantial frequency of HIV infected persons who were not virally suppressed in Western Europe throughout this decade," Atkins added. "With such a big number of persons who were not virally suppressed, a novel variation may have evolved from the virus population."

According to Wymant, the tree revealed that those who got the VB variety carried "viruses that were abnormally closely connected to each other." This data shows that there was minimal viral evolution between the time someone got the virus and when they passed it on to someone else.

In other words, the VB variety of HIV may be more transmissible than other HIV strains, in addition to being more pathogenic. This conclusion, however, is less compelling than evidence of enhanced virulence since the tree only gives indirect proof of the virus's transmissibility, according to Wymant.

Following the emergence of the VB variety in the 1980s or 1990s, the number of persons infected with it continuously climbed until around 2010. The proportion of new VB cases among all new subtype B cases began to rise at the same period. The scientists discovered that the rise peaked in 2008 and subsequently gradually dropped.


"This is most likely a by-product of the Netherlands' significant efforts to reduce HIV transmission, regardless of variation," Wymant added. Absolute numbers of both VB and non-VB diagnoses were dropping at the time, and the exact ratio of VB to non-VB infections was unknown, according to the authors.

The finding of a very virulent HIV variation isn't entirely unexpected, according to Wertheim. "This discovery is consistent with evolutionary theory as well as long-term patterns in rising virulence in the United States," he told Live Science. "How sharp and clear this freshly characterized cluster is astounds me."

Looking forward, Many organisations throughout the world will begin examining their data to determine if the VB strain has spread outside the Netherlands, according to Wertheim. "I'm also intrigued if comparable mutations have appeared elsewhere in the world," Wertheim added.

Aside from the examples reported in Switzerland and Belgium, the researchers found no other first evidence of the variation outside of the Netherlands. They looked through publicly accessible viral genetic sequences and discovered nothing, although Wymant believes there may be a few more people infected with the variation who haven't been recognized yet.

"We are allowing other investigators in various nations to evaluate their own private data by making the genetic sequence of the VB variation freely available," he added.

Future research on the VB variety might show how it accumulates in the blood and decimates CD4 cells so swiftly, as well as more information about how it initially developed. The researchers discovered evidence that the variation gradually picked up mutations one by one over time, but they couldn't identify if this happened in numerous people or simply one, according to Wymant.

Should the general public be concerned about the newly discovered VB version in the meantime?

"There is no cause for the public to be concerned," Wymant added. "The discovery of this variation highlights the relevance of existing guidance: that those at risk of contracting HIV have access to frequent testing to enable for early identification and treatment... The VB version is subject to the same rules."

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