內文 :
若說新冠肺炎對世人有何教誨,那就是病毒會不斷變異,COVID-19如是,愛滋病(AIDS)肇因HIV病毒也不例外。最新研究發現,某種HIV突變株 ,傳染力更強、致病率更高,萬萬不可輕忽。

 

HealthDay 報導,該變異株名為VB,早在30年前就已現蹤,但如今才獲一組跨國基因研究人員確認,患者至少109名,多在荷蘭。相較於全球愛滋病患者,數目雖少,但毒性更強,不及早治療,恐藥石罔效。

 

與HIV其他突變種相較,帶有VB變異株的患者,病毒量是一般患者的3.5至5.5倍,傳染力也較強。30多歲的患者,病程惡化快速,約於九個月內就可能演變為重症,年紀越長,惡化速度更快。

 

愛滋病即後天免疫缺乏症候群,患者抵抗力降低,從而引發各種病症。VB的可怕之處在於,它會使人體的CD4細胞數量快速下降,而CD4是至關重要的人體免疫細胞。

 

所幸目前的反轉錄病毒療法(active antiretroviral therapy,ART),可成功抑制VB。因此專家強調,此一發現的重要性在於,有疑慮者,務必儘早檢查,愈早介入治療,投入抗病毒藥物,愈能控制病情,即便遭高毒性HIV侵襲,也無須太過擔憂。

 


More Destructive Variant of HIV Spotted in the Netherlands

 

If the pandemic taught the world nothing else, it's that viruses can mutate, potentially giving rise to new and more harmful variants.

 

Now, new research reveals that's exactly what has happened with HIV, the virus that causes AIDS.

 

Called VB (for virulent subtype B), the "new" HIV variant actually seems to have emerged more than 30 years ago. But its existence was only recently confirmed by a team of genetic researchers from the United States, the United Kingdom, the Netherlands, France, Sweden, Germany, Switzerland and Finland.

 

That it has largely flown under the radar may reflect the fact that the VB variant has only been found in 109 HIV-positive patients so far, most of them Dutch. But although not widespread, the concern is that — absent preventive treatment — the variant seems to attack a patient's immune system much more aggressively than more common strains.

 

Even so, study author Chris Wymant, a senior researcher in statistical genetics and pathogen dynamics with the University of Oxford's Big Data Institute, is adamant that "the public needn't be worried."

 

For one thing, he noted that while there may be more VB-infected patients than is currently known, the number is "unlikely to be dramatically higher than what we found." The 109 patients already identified are not, Wymant said, "the tip of the iceberg."

 

And most critically, existing antiretroviral therapies (ART) remain very effective at keeping the VB variant at bay.

 

So, the real value of this discovery is to re-emphasize "the importance of [the] guidance that was already in place — that individuals at risk of acquiring HIV have access to regular testing to allow early diagnosis, followed by immediate treatment," Wymant explained.

 

"This limits the amount of time HIV can damage an individual's immune system and jeopardize their health," he noted. "It also ensures that HIV is suppressed as quickly as possible, which prevents transmission to other individuals."

 

In the Feb. 4 issue of Science, Wymant and his colleagues described how the new variant was first discovered through the ongoing efforts of the so-called BEEHIVE project.

 

BEEHIVE was launched in 2014 in recognition of the fact that "HIV mutates so quickly that every individual has a virus which is different from everyone else's," Wymant said, though he stressed that, as a practical matter, "the large majority of these mutations make no difference."

 

But Wymant pointed out that among those not already on a one-pill-a-day ART regimen, HIV seems to affect patients "in a remarkably variable way."

 

"Some progress to AIDS within months," he noted, "while others do not progress after decades. Some have viral loads — levels of virus — thousands of times higher than others. [And] research by our team, and others before the BEEHIVE project, established that this variability is partly due to the virus, not only due to people's immune systems varying in their ability to fight the virus."

 

So, the BEEHIVE scientists set out to continuously monitor incoming data from seven different HIV studies across Europe and Africa, with the goal being to identify and track any viral changes that might significantly alter the way a virus that has already claimed 33 million lives behaves.

 

Enter the VB variant, which was initially identified in just 15 patients in the Netherlands, one in Switzerland and one in Belgium. A subsequent deep dive into the viral underpinnings of more than 6,700 HIV-positive patients unearthed another 92 VB-infected patients.

 

The investigators found that patients infected with the VB variant had HIV viral loads amounting to 3.5 to 5.5 times higher than would be found in patients infected with other known variants. The VB variant was also found to be much more transmissible.

 

And absent treatment, the team observed that, on average, VB-infected patients in their 30s progressed to "advanced HIV" in just nine months. That is much faster than is typical among those infected with other variants, said Wymant, with older patients likely to experience even quicker disease progression.

 

Why? Because of a far faster drop in the patient's CD4 cell count, a key marker for immune system damage.

 

Still, the good news is very good: once VB-infected patients are put on antiretroviral therapy, survival rates were just as strong as with any other HIV variant. And while acknowledging that even more deadly variants may eventually surface, Wymant noted that, so far, "this is an example of something that thankfully seems to be rare."

 

The main message is that "we need to ensure timely HIV diagnosis and rapid provision of antiretroviral drugs," agreed Joel Wertheim, an associate professor in the department of medicine at the University of California, San Diego.

 

"Viruses are constantly evolving," Wertheim noted. "The COVID-19 pandemic keeps reminding us of that in real-time."

 

That means that "HIV testing is as important as ever," he stressed. "If people don't know they've been infected, they can't take the precautions needed to limit transmission. This is true regardless of HIV variant, and doubly so where this more virulent variant has been observed."

 

from https://consumer.healthday.com/2-5-more-destructive-variant-of-hiv-spotted-in-the-netherlands-2656519350.html