The human immunodeficiency virus (yellow) infecting a human cell. (National Cancer institute/Unsplash)
Affected individuals at risk of progressing to AIDS ‘much more rapidly’
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A human immunodeficiency virus (HIV) variant has been discovered in the Netherlands by researchers at Oxford University, who say the variant is highly infectious and more damaging than other HIV variants and can put individuals at risk of developing AIDS “much more rapidly.”
HIV is a virus that attacks the body’s immune system, which can lead to AIDS if not treated. The World Health Organization (WHO) estimates that 30.2–45.1 million people were living with HIV at the end of 2020, with over two thirds of them (25.4 million) in the WHO African Region.
The newly discovered variant, named “VB” for virulent subtype B, showed significant differences compared with other HIV variants. Specifically, prior to antiretroviral treatment, people with the VB variant had a viral load (the level of the virus in the blood) of between 3.5 and 5.5 times higher. They also showed a higher risk of transmitting the virus to others.
Furthermore, the rate of CD4 cell decline—considered the marker of immune system damage by HIV—was twice as fast in people with the VB variant, which makes them at risk of developing AIDS “much more rapidly,” according to a release from the University of Oxford.
“Before this study, the genetics of the HIV virus were known to be relevant for virulence, implying that the evolution of a new variant could change its impact on health. Discovery of the VB variant demonstrated this, providing a rare example of the risk posed by viral virulence evolution,” lead author Chris Wymant said in a statement.
Fortunately, those with the VB variant responded similarly to antiretroviral treatment, the standard treatment for HIV, and had similar survival rates to people with other HIV variants.
Citing how the newly discovered variant can damage the immune system more rapidly, researchers said it is “critical” that people at higher risk of contracting HIV have access to frequent testing to get diagnosed early and start treatment as soon possible.
Early detection and treatment “limits the amount of time HIV can damage an individual’s immune system and jeopardize their health,” senior author Christophe Fraser said in a statement. “It also ensures that HIV is suppressed as quickly as possible, which prevents transmission to other individuals.”
Without treatment, people with the VB variant could progress to AIDS within two to three years of their initial HIV diagnosis, compared to an average of six to seven years after diagnosis with other HIV variants.
The peer reviewed study was published in the journal Science on Feb. 3.
Scientists noted that they cannot deduce any single genetic cause for the VB variant, which has many mutations spread throughout the genome.
The variant is estimated to have arisen in the late 1980s to 1990s. Researchers were alerted to the VB variant from another ongoing study, called the BEEHIVE project, which collects test samples from across Europe and Uganda.
They found that 17 of the HIV-positive people in the BEEHIVE study had a “distinct subtype-B viral variant” with viral loads that were “highly elevated” in the 6–24 month period after a person had a positive test in the early stage of their infection. Of the 17 people, 15 came from the Netherlands.
From there, researchers analyzed data from a cohort of some 6,706 HIV-positive people in the Netherlands, from which they found 92 more people infected with the viral variant, bringing the total of people confirmed to have the VB variant to 109.
The “first sampled VB individual” was diagnosed with HIV in 1992, researchers wrote.
After analyzing the patterns of genetic variation among the samples, scientists estimated that the VB variant first arose in the late 1980s or early 1990s in the Netherlands, after which it spread faster compared to other variants in the 2000s, although the spread has been declining since around 2010.
“The research team believe that the VB variant arose in spite of widespread treatment in the Netherlands, not because of it, since effective treatment can suppress transmission,” according to the University of Oxford release.
“The individuals with the VB variant showed typical characteristics for people living with HIV in the Netherlands, including age, sex, and suspected mode of transmission. This indicates that the increased transmissibility of the VB variant is due to a property of the virus itself, rather than a characteristic of people with the virus.”