科學家說，一個「高致病性」的愛滋病毒株但「無需驚慌」
據研究人員稱，新發現更具傳染性的 HIV 毒株可能於 1990 年代開始在荷蘭傳播，並且對治療反應良好。
資料來源：NBC 新聞；2022 年 2 月 4 日，作者：班傑明·瑞安；財團法人台灣紅絲帶基金會編譯
一個國際研究小組已經確定了一種高毒性和傳染性的 HIV 毒株，該毒株可能於 1990 年代開始在荷蘭傳播，並感染了 100 多人。
如果不加以治療，與典型的 HIV 疾病進展相比，這種病毒株會導致血液中的病毒水準高得多，關鍵免疫細胞的下降速度增加一倍。
該研究小組由牛津大學的科學家領導，他們在阿姆斯特丹的一個愛滋病基金會（Stichting HIV Monitoring） 做出了重要貢獻，他們強調這些發現並不值得恐慌。這種特殊的 HIV 毒株對抗反轉錄病毒治療反應良好，這對阻斷傳播具有額外好處。雖然該病毒株仍可能傳播給新人，但一旦患有該菌株的人開始治療，它與疾病或死亡風險的增加無關。
加州大學聖地亞哥分校的臨床病毒學家 Douglas D. Richman 博士沒有參與這項研究，他稱讚這篇週四發表在《科學》雜誌上的新論文是「第一篇針對 HIV 變異株似乎變得更加兇猛令人信服的描述」。
「最重要的帶回家的課題是，它不像這裡或那裡的新 omicron 變異株，我們將遇到新一波的一些可怕問題」，Richman 說。
不過，西雅圖弗雷.哈欽森癌症研究中心（Fred Hutchinson Cancer Research Center in Seattle）的病毒學家邁克爾·埃默曼（Michael Emerman）對該論文對大眾想像的潛在影響表示擔憂，並預計「它將被解釋為存在一種致命的超級 HIV 毒株」。
關於 HIV 流行的溝通如何引起不必要的公眾恐慌是有先例的。
2005 年，紐約市的研究人員發現，當地一名男同性戀者最近感染了一種他們認為具有高度毒性的 HIV 毒株——他在感染後不到 20 個月就患上了愛滋病——並且對紐約市的抗反轉錄病毒治療具有廣泛的抗藥性。那時。該男子報告說習慣性地使用冰毒，並且經常與多個伴侶發生性行為而沒有使用保險套。
傳染病醫生湯姆.弗里登（Tom Frieden）博士當時是紐約市衛生和心理衛生局局長，後來被任命為疾病控制和預防中心主任，他於 2005 年 2 月召開新聞發布會，宣布調查結果和警告這個人的案子可能預示著對公共健康的嚴重威脅。該公告引發了對所謂超級病菌的全球恐慌，新論文的作者渴望避免這種情況。
最後，紐約市男子的病毒對治療反應良好，沒有發現其他如此迅速發展的 HIV 病例。
正如厭倦了 Covid-19 的公眾透過新的冠狀病毒變異的出現了解到的那樣，病毒總是在不斷發展。偶然突變有時會給病毒帶來選擇性優勢。然後，新的變異版本可以因此傳播得更廣泛。
新論文的作者最初確定了 17 個人，他們都是歐洲和烏干達愛滋病毒感染者研究的成員，他們在診斷後具有異常高的病毒載量。其中 15 人還在荷蘭的另一項世代研究中被登記，其中一人住在比利時，另一人住在瑞士。
接下來，研究人員撒下了更大的網，檢查了參與另一項荷蘭研究的 HIV 感染者的 6,706 份血液樣本。在那裡，他們發現了另外 92 人，根據基因分析，他們都生活在一種密切相關的、高毒力的 HIV 毒株中。
有跡象表明，這種病毒株在荷蘭以外的傳播範圍可能不大。研究人員通過分析瑞士一項針對愛滋病毒感染者的大型研究樣本確定了這一點——該世代涵蓋了自 2009 年以來該國約 90% 的診斷。在那裡，他們只發現了三名攜帶相關病毒株的人，包括之前的一名確定的瑞士人。
通過分析 109 名相關 HIV 毒株患者的治療前疾病軌跡，科學家們觀察到病毒載量通常比更廣泛的世代研究中的其他相同 HIV 亞型、但不同病毒株之6,604 人高出 3.5 倍至 5.5 倍。（HIV 亞型是比毒株更廣泛的遺傳類別。）統計分析表明，在攜帶特別毒力病毒的人中，CD4 免疫細胞的下降速度加倍，這與高病毒載量無關。
根據這些發現，研究人員預測，如果不進行治療，攜帶高毒力 HIV 毒株的人可能會在診斷後的兩到三年內患上愛滋病，相較於對照組如預期中典型的六到七年。
就年齡、性別、疑似 HIV 感染方式和出生地而言，兩組的總體特徵相似。這有助於研究人員得出結論，病毒遺傳密碼的數百種突變可能是導致該菌株效力和傳染性增加的原因，而不是感染該病毒株的人之遺傳或營養或其他感染等環境因素。
這種毒株的最早證據是在 1992 年被診斷出患有 HIV 的個體身上。然後，它在荷蘭默默傳播了幾十年，比新論文的作者們配備了他們參與開發用於分析病毒遺傳學的尖端工具可檢測到早了幾十年。
亞特蘭大埃默里疫苗中心的分子病毒學家埃里克.亨特（Eric Hunter）沒有參與這項研究，他說他期待未來對這種愛滋病毒株的後續研究可能會揭示出對其起源和疾病軌蹟的進一步見解。
「了解這些個體疾病進展更快的病毒或分子基礎是什麼特別有趣」，亨特說。
新研究的主要作者、牛津大學醫學系的流行病學家克里斯.懷曼特（Chris Wymant）重申，他的團隊的發現「沒有理由驚慌」。
Wymant 指出，廣泛採用的應對全球 HIV 流行病的指南——廣泛檢測和診斷後立即開始治療——可以幫助識別任何可能感染這種病毒株的人，並確保它不會不成比例地影響他們的長期健康前景。
根據聯合國愛滋病毒/愛滋病聯合規劃署和疾病預防控制中心的數據，全世界估計有 3,800 萬人感染艾滋病毒，其中約 120 萬人在美國。全球每年約有 150 萬例 HIV 傳播，其中包括約 37,000 例美國新病例。
A ‘highly virulent’ HIV strain is ‘no cause for alarm,’ scientists say |
The newly identified, more infectious strain of HIV likely began circulating in the Netherlands in the 1990s and responds well to treatment, according to researchers.NBC News
Feb. 4, 2022,By Benjamin Ryan
An international research team has identified a highly virulent and infectious strain of HIV that likely began circulating in the Netherlands in the 1990s and has infected more than 100 people.
Left untreated, this viral strain leads to a much higher level of virus in the blood and a doubled rate of decline in key immune cells compared with the typical HIV disease progression.
The research team, led by scientists at the University of Oxford with key contributions from Stichting HIV Monitoring in Amsterdam, has stressed that these findings are not cause for alarm. This particular HIV strain responds well to antiretroviral treatment, which has the added benefit of blocking transmission. While the strain could still be transmitting to new people, once someone with the strain starts treatment, it is not associated with an increased risk of illness or death.
Dr. Douglas D. Richman, a clinical virologist at the University of California, San Diego, who was not involved with the study, praised the new paper, published Thursday in Science, as “the first compelling description of an HIV variant that appears to be more virulent.”
“The most important take-home lesson is, it’s not like a new omicron variant here and that we’re going to have a new wave of some terrible problem,” Richman said.
Michael Emerman, a virologist at the Fred Hutchinson Cancer Research Center in Seattle, nevertheless expressed concern about the paper’s potential impact on the popular imagination, anticipating “that it’s going to be interpreted that there’s a deadly super-HIV strain.”
There is precedent for how communicating about the HIV epidemic can cause needless public panic.
In 2005, researchers in New York City discovered that a local gay man had recently contracted an HIV strain that they believed was both highly virulent — he became sick with AIDS no more than 20 months following infection — and broadly resistant to the antiretroviral treatments available at that time. The man reported habitual crystal meth use and frequent sex without a condom with multiple partners.
Dr. Tom Frieden, an infectious disease physician who was then the commissioner of the New York City Department of Health and Mental Hygiene and was later appointed director of the Centers for Disease Control and Prevention, held a February 2005 news conference announcing the findings and warning that this man’s case could portend a grave threat to public health. The announcement ignited a global panic over the so-called superbug, a situation the authors of the new paper are keen to avert.
In the end, the virus in the New York City man responded well to treatment, and no other cases of such rapidly advancing HIV were identified.
As the Covid-19-weary public has learned through the emergence of new coronavirus variants, viruses are always evolving. Chance mutations will at times lend a selective advantage to a virus. Then the new, mutated version can spread more widely as a result.
The authors of the new paper initially identified 17 individuals, all members of a study of people living with HIV in Europe and Uganda, who had unusually high viral loads following diagnosis. Fifteen of them were also registered in a separate cohort study based in the Netherlands, while one person lived in Belgium and another in Switzerland.
Next, the investigators cast a wider net, examining 6,706 blood samples from people with HIV participating in the separate Dutch study. There, they found an additional 92 people who, according to genetic analyses, were all living with a closely related, highly virulent HIV strain.
Signs suggest this strain might not have spread much outside the Netherlands. The researchers determined this by analyzing samples from a large study of people living with HIV in Switzerland — a cohort that covers about 90 percent of the nation’s diagnoses since 2009. There, they only found three people with the related viral strain, including the one previously identified Swiss individual.
Analyzing the pre-treatment disease trajectory of the 109 people with the related HIV strain in question, the scientists observed a viral load that was typically 3.5-fold to 5.5-fold higher compared with 6,604 other people in the wider cohort study who had the same HIV subtype but a different strain. (An HIV subtype is a broader genetic category than a strain.) The doubled rate of decline in CD4 immune cells seen in those with the especially virulent virus, a statistical analysis indicated, occurred independently of the high viral load.
Based on these findings, the investigators projected that without treatment, people with the highly virulent HIV strain would likely develop AIDS within just two to three years of diagnosis, compared with the more typical six to seven years expected in the comparison group.
The overall characteristics between the two groups were similar when it came to their age, sex, suspected mode of HIV acquisition and place of birth. This helped the investigators conclude that hundreds of mutations to the virus’s genetic code were likely responsible for the strain’s increased potency and infectiousness, not the genetics of the people who contracted the strain or environmental factors such as nutrition or other infections.
The earliest evidence of this strain was in an individual diagnosed with HIV in 1992. It would then spread silently in the Netherlands for decades before the authors of the new paper, armed with cutting-edge tools they had a hand in developing for analyzing viral genetics, would detect it.
Eric Hunter, a molecular virologist at the Emory Vaccine Center in Atlanta who was not involved in the study, said he looked forward to future research of this HIV strain that might reveal further insights into its origins and disease trajectory.
“It would be particularly interesting to understand what was the viral or molecular basis for that more rapid disease progression in these individuals,” Hunter said.
Chris Wymant, the new study’s lead author and an epidemiologist in the department of medicine at the University of Oxford, reiterated that his team’s findings are “no cause for alarm.”
Wymant noted that broadly adopted guidelines for tackling the global HIV epidemic — widespread testing and immediate initiation of treatment following diagnosis — could help identify anyone who might contract this viral strain and ensure it did not disproportionately impact their long-term health prospects.
An estimated 38 million people are living with HIV worldwide, about 1.2 million of whom are in the United States, according to the Joint United Nations Program on HIV/AIDS and the CDC. There are approximately 1.5 million HIV transmissions globally each year, including about 37,000 new U.S. cases.