A new, more virulent and transmissible form of HIV has been discovered in Europe, infecting at least 109 people.

On February 3, academic journal science specialized papers to introduce the new HIV variants, the university of Oxford and the university of Amsterdam in the Netherlands, researchers in institutions such as named VB mutant strains, said its viral load is 3.5 to 5.5 times of ordinary after HIV infection, CD4 cells decreased for two times, in the case of the untreated, Intermediate stage of HIV infection is about 9 months after infection, compared with about 3 years for normal HIV infection.

The VB mutant may have existed for more than 30 years and is caused by de novo mutation of the virus rather than gene recombination. Its origin, virulence and infectivity… There are still plenty of mysteries to be solved.

The virus has been around for 30 years

In a previous study, researchers found that 17 hiv-infected people, 15 from the Netherlands, were infected with a new and unknown HIV mutation. When the study was expanded, 92 additional cases of infection with the new mutant strain were found.

Let’s start with some data on the VB mutant.

Without treatment, CD4 cells decreased to 350 cells/mm³ in patients with the VB mutant in about 9 months, compared with 36 months in patients with conventional HIV. And enter the commonly recognized onset of AIDS, VB mutant infection about 2 to 3 years, routine infection about 6 to 7 years.

To explain the surge in virulence, the researchers looked at the mutant genome of the VB strain for clues. The report shows that the VB mutant carries a variety of mutations, with significant changes in its genome affecting nearly 300 amino acids. However, the genetic causes of increased virulence cannot be determined at a specific point due to their dispersion.

The mortality rate after treatment was similar to that of conventional HIV infection. This is because existing antiretroviral drugs, the standard treatment for HIV, are not less effective against VB mutant strains. At the same time, this may be one of the reasons why the VB mutant strain has not completely replaced conventional HIV.

In short, the virulence of the VB mutant and the duration of treatment are mutually affected. Due to the virulence of the VB mutant strain, both morbidity and mortality increase when untreated. However, due to the stronger virulence and shorter incubation period of VB mutant strain, the time for patients to show symptoms is faster, which accelerates the timely intervention of medical treatment.

How is the VB mutant produced? The researchers have yet to draw a definitive conclusion.

Unlike the emergence of drug-resistant bacteria as a result of antibiotic overuse, it is not a result of “survival of the fittest”, as existing AIDS drugs remain sensitive to the VB mutant. Researchers have tentatively concluded that the mutation is likely due to the fact that the original infected person did not receive treatment for a long time.

Using statistical models of the data, the researchers found that the VB mutant was likely to have appeared in the Netherlands as early as the 1980s and had been spreading faster than other mutants in the early 2000s, but the rate of spread slowed significantly after 2010.

For similar reasons, rapid detection and intervention also reduced the risk of high-risk transmission of HIV infection, while screening and treatment were not fully available.

“Possible more deadly Novel Coronavirus variant”

“Is it ‘sleep on brushwood and taste gall’, or short high-gloss burning?” In an accompanying editorial, Professor Joel Wertheim, an expert on viral evolution at the University of California, San Diego, said the less virulent HIV is and the lower its viral load, the longer its host lives but the less able it is to spread. On the contrary, the host enters the onset stage more quickly and is more transmissible, but the transmission time is shorter.

Naturally, viruses tend to choose the middle ground. However, medical intervention has made the factors more complicated, and the selective drivers behind the evolution of HIV are still not fully explained.

The scientists hope to clarify the balance between virulence, infectivity and treatment. Previous studies have tried to determine the best time to treat HIV. One idea is that:

Without treatment, HIV is less likely to mutate into a more virulent form because the host becomes ill quickly, limiting transmission opportunities. And once too early, too wide spread treatment, may accelerate the emergence of highly virulent HIV.

The simple answer is, “If you’re going to be blocked, you might as well be more virulent.”

Credit: Cavallini James/BSIP/Science Photo Library

But the VB mutant was created before drugs were widely available, and this time the researchers suggest a different conclusion: widespread treatment helps prevent new virulent variants, because treatment reduces the progression of transmission, regardless of virulence.

In other words, if viruses can’t replicate, they can’t mutate.

The researchers also stressed that because the VB mutant is more harmful to the body’s immune system, early diagnosis and early treatment are crucial.

In addition, this research is further extended to the field of novel Coronavirus. Scientists believe the finding points to the risk of a more deadly novel Coronavirus variant.

“The emergence of Omicron contributes to the idea that novel Coronavirus is becoming less lethal, but that is not how novel Coronavirus has evolved.” Dr Emma Hodcroft, a molecular epidemiologist at the University of Bern in Switzerland.

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Professor Chris Wymant, one of the authors of the paper, said the discovery of the VB mutant was a warning: “We should not underestimate the evolutionary potential of viruses or be overconfident that they will only evolve in milder, less virulent directions.”

“Since the first AIDS discovery in the United States in 1981, the viral load of patients at diagnosis has increased every decade, both before and after treatment became widely available.” Professor Joel Wertheim said it was unclear how the virus would evolve in the future in response to human “siege”.

But he also stressed that the emergence of a more virulent and contagious FORM of HIV was not a public health crisis and that existing methods of screening and treatment could still be effective.