Highlights
- The variant increases the number of HIV virus particles in the blood of infected individuals.
- People with virulent subtype B (VB) exhibits a higher number of viral particles in an infected person’s blood.
- It makes infected individuals more likely to transmit the virus, researchers claim.
SCIENTISTS have found a “mutated” HIV strain that causes more severe illness — and is more transmissible.
The researchers reported the subtype-B variant of HIV-1 with “exceptionally high virulence”. The journal Science, which reported about the findings on February 3, 2021, based their report on an Oxford team’s analysis of more than 100 people infected with the new-found variant.
The findings were also reported in Nature.
What we know so far:
What is the variant called?
Oxford scientists who found the new variant called it the HIV virulent subtype B — or “VB”.
Where was the new HIV strain detected?
The highly transmissible and damaging variant of HIV has been circulating in The Netherlands — possibly for the past two decades — according to the researchers.
What happens to people with VB compared to more common HIV variant?
The researchers found the following:
Individuals with the VB variant had a “viral load” (the level of the virus in the blood) between 3.5 and 5.5 times higher.
- Individuals with the VB variant had a “viral load” (the level of the virus in the blood) between 3.5 and 5.5 times higher.
- Researchers found that rate of decline of CD4 cells (an indicator of immune system damage by HIV) occurred twice as fast in individuals with the VB variant.
- A drop in CD4 T cells, which help to coordinate the body’s immune response to infections, is a tell-tale sign that HIV has damaged the immune system.
- VB-infected people are at greater risk of developing AIDS much more rapidly than those with other versions of HIV.
- This places them at risk of developing AIDS much more rapidly.
- Individuals with the VB variant also showed an increased risk of transmitting the virus to others.
- People with VB showed significant differences before anti-retroviral treatment compared with individuals infected with previous HIV variants.
How common are viral mutations?
Viral mutations are not uncommon. Recently, a 22-year-old COVID-infected HIV patient had developed 21 mutations, according to one study.
However, if two strains infect the same person, they can combine to form a cross between the two — known as a recombinant.
Within group M there are known to be at least nine genetically distinct subtypes of HIV-1. These are subtypes A, B, C, D, F, G, H, J and K, according to Avert, the global information and education on HIV and AIDS.
Do existing HIV drugs work against the new strain?
Experts said the existing known HIV drugs are still effective against the new HIV variant, and the mutations found in VB don’t make it resistant to existing HIV drugs.
Joel Wertheim, an evolutionary biologist and molecular epidemiologist at the University of California San Diego told Nature. “All of the tools in our arsenal should still work.”
In general, successful treatment with anti-retroviral drugs suppresses viral load and interrupts the decline in CD4 counts that would otherwise lead to AIDS.
How many were found infected with “VB”, the new HIV strain?
The study stated 109 individuals were found with this variant. More important: they had up to 5.5-fold increase in “viral load” — and a twice-as-fast decline in CD4 cell — as 6604 individuals with other subtype-B strains.
Without treatment, advanced HIV — CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences — is expected to be reached — on average, 9 months after diagnosis for individuals in their thirties with this variant.
HIV attacks and destroys the infection-fighting CD4 cells (CD4 T lymphocyte) of the immune system. Loss of CD4 cells makes it hard for the body to fight off infections and certain HIV-related cancers.
The researchers attributed the increased virulence to the viral strain — as the age, sex, suspected mode of transmission, and place of birth for the 109 individuals were typical for HIV-positive people in the Netherlands.
How does HIV spread?
Most scientific literature state that HIV mostly passes between people through body fluids, including the following:
▶ Blood
▶ Semen, pre-seminal fluid
▶ Rectal fluids
▶ Vaginal fluids
▶ Breast milk.
When did the 'new' variant originally arise?
Researchers cite genetic sequence analysis suggesting that this variant with higher transmissibility arose in the 1990s from “de novo” (from the beginning) mutation — instead of recombination. It also had “an unfamiliar molecular mechanism of virulence,” they added.
The main (M) group of HIV-1, seen behind the global pandemic, is thought to have first emerged around 1920 in the area of what is now Kinshasa, Democratic Republic of the Congo.
It had diversified into subtypes by 1960. Given what is known about the new strain VB, the researchers it is important to continue monitoring HIV virulence.
What does “greater virulence” mean?
Greater virulence simply means giving a viral strain ability to cause greater damage to their hosts. Extensive population-level studies show the risk posed by viruses evolving to greater virulence.
How is virulence measured?
HIV-1 virulence is most commonly measured by viral loads (the concentration of viral particles in blood plasma) and CD4 counts (the concentration of CD4+ T cells in peripheral blood, which tracks immune system damage by the virus).
How was the highly virulent variant discovered?
One was through the “Beehive” project of Oxford (on individuals enrolled in eight cohorts across Europe and Uganda). It identified a group of 17 individuals with a distinct subtype-B viral variant. The 17 individuals with the distinct viral variant comprised 15 participants in the “Athena” study in the Netherlands, 1 from Switzerland, and 1 from Belgium.
ART cannot cure HIV, but HIV medicines help people with HIV live longer, healthier lives. ART also reduces the risk of HIV transmission.
It prevents HIV from multiplying (making copies of itself), which reduces the amount of HIV in the body (called the viral load). Having less HIV in the body gives the immune system a chance to recover and produce more CD4 cells.
Even though there is still some HIV in the body, the immune system is strong enough to fight off infections and certain HIV-related cancers.
What if VB-infected people go untreated?
The researchers estimate that, without treatment, people infected with this variant would develop AIDS within 2–3 years after diagnosis, compared with 6–7 years for those infected with other HIV strains.
We are not overly worried about this new variant.
Are experts worried?
No. “We are not overly worried about this new variant,” says Meg Doherty, director of the Global HIV, Hepatitis and Sexually Transmitted Infections Programmes at the WHO.
But the emergence of a more virulent form of HIV is “a reason to stay vigilant” — though it’s not a public-health crisis.
Experts also said the study findings underscore need for pandemic preparedness and surveillance. It also study highlights the importance of widespread HIV testing and treatment services in order to identify infected people quickly and start treatment early, because treatments work well, even against this variant.
“With proper treatment, we now expect people with HIV to live a normal life span,” says Dr. Michael Horberg, national director of HIV/AIDS for Kaiser Permanente.
Since 1996, with the advent of highly active, antiretroviral therapy, a person with HIV with good access to antiretroviral therapy (ART) can expect to live a normal life span, so long as they take their prescribed medications.
