科學家窺見新疫情的起源（2/2）

Recently the New York Times reported the following:

Scientists Get a Glimpse of How New Pandemics Are Made (2/2)

Researchers have devised a new tool for discerning between naturally occurring viral outbreaks and those resulting from lab accidents.

The NYT - By Carl Zimmer

March 9, 2026

Updated 9:43 a.m. ET

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Since then, researchers have not found direct evidence to test this scenario or others like it. But the new study by Dr. Wertheim and his colleagues concluded that the 1977 virus underwent some odd evolution before the pandemic — and that the mutations it gained bear patterns identical to those found in viruses that are grown in labs.

Gigi Gronvall, a biosecurity expert at Johns Hopkins University, said that the new study suggests that the 1977 pandemic began as a vaccine trial. “It’s more evidence that they were trying to create an attenuated vaccine and failed spectacularly,” she said.

Spyros Lytras, a virologist at the University of Tokyo who was not involved in the new study, said the study’s methodology offered a new tool for tracing the origin of outbreaks. “The genetic data holds a robust signal that can distinguish between lab passaging and manipulations versus natural spillovers,” he said.

James Lloyd-Smith, a disease ecologist at the University of California, Los Angeles, said that detecting the genetic signature of lab evolution in the Russian flu was “very cool.” But he cautioned that scientists typically only capture a fraction of the evolution of viruses in their samples. “This approach isn’t a magic wand, and the study still faces the same challenges of limited data that have dogged the field,” he said.

Of the several outbreaks that Dr. Wertheim and his colleagues analyzed, only the Russian flu proved to be an exception to the rule. The virus that caused Covid — SARS-CoV-2 — was not.

The researchers found no peculiar changes in SARS-CoV-2 before it jumped into humans. It gained mutations as it spread from bat to bat, just like other bat coronaviruses did; only after the virus emerged in humans did it undergo a marked shift. Within a year, radically new variants were evolving, with mutations that made them exquisitely well-adapted to humans.

The new study adds to the ongoing debate over Covid’s origins. In a January interview with The New York Times, Dr. Jay Bhattacharya, the director of the National Institutes of Health, asserted that SARS-CoV-2 emerged from a lab. “I think if you just focus on the scientific evidence alone, I would say it’s certain,” he said.

Some experts who favor a lab-leak origin point to just how well prepared SARS-CoV-2 was to spread among humans from the start of the pandemic. In November, Dr. Robert Redfield, former director of the Centers for Disease Control and Prevention, claimed that the Chinese military had created SARS-CoV-2 as an inhaled vaccine. “I think that was all engineered,” Dr. Redfield said in a podcast interview.

But last month, a group of experts assigned by the World Health Organization to examine Covid’s origins came down in favor of SARS-CoV-2 having originated in bats, which then passed it to animals sold in a market in Wuhan.

“Most of the peer-reviewed scientific evidence supports this hypothesis,” the scientists noted.

Dr. Wertheim has helped collect some of that peer-reviewed scientific evidence. The new study adds more evidence in favor of an animal origin, he said.

If SARS-CoV-2 was reared in a lab, its mutations would unfold in a pattern like that of the Russian flu. Instead, Dr. Wertheim and his colleagues found, its mutation pattern matched the five naturally occurring outbreaks they studied.

Instead, Dr. Wertheim said, Covid appears to have arisen from some really bad luck. As the precursor virus was adapting to infect bats, it ended up ready to start a pandemic among people. “It’s coincidentally exceptionally good at being a human virus,” Dr. Wertheim said.

David Robertson, a virologist at the University of Glasgow who was not involved in the new research, said that the study offered insights not just for Covid but for any zoonotic virus — a virus that spreads from animals to humans. “It’s a key point for understanding zoonotic risk,” he said. “Viruses can be circulating in nature without requiring adaptations to infect or transmit successfully in humans.”

If that’s the case across a wide range of zoonotic viruses, Dr. Wertheim said, we can expect more pandemics in the future. “It’s what we don’t know that’s going to get us,” he said. “They’re out there, and they’re ready to go.”

Translation

科學家窺見新疫情的起源（2/2）

研究人員開發出一種新工具，用於區分由自然發生的病毒爆發疫情和由實驗室事故導致的爆發

（繼續）

此後，研究人員尚未找到直接證據來驗證此假設或其他類似假設。但Wertheim博士及其同事的一項新研究得出結論：1977年的病毒在大流行之前經歷了某種奇特的進化 - 而且它獲得的突變模式與實驗室培養的病毒的突變模式完全相同。

約翰霍普金斯大學的生物安全專家Gigi Gronvall表示，這項新研究表明，1977年的疫情始於一次疫苗試驗。 她說:「這進一步證明，他們當時試圖研發減毒疫苗，結果卻慘敗了」。

並未參與這項新研究的東京大學病毒學家Spyros Lytras表示，該研究的方法為追蹤疫情起源提供了一種新工具。他說: 「基因數據包含一個可靠的訊號，可以區分實驗室傳代和人為操作，相對於自然溢出」。

加州大學洛杉磯分校疾病生態學家James Lloyd-Smith表示，在俄羅斯流感中檢測到實驗室進化的基因特徵是「非常酷」的事。但他提醒說，科學家通常只能捕捉到病毒樣本中演化過程的一小部分。他說: 「這種方法並非萬能，這項研究仍然面臨著數據有限的挑戰，而數據有限一直是該領域長期存在的難題」。

在Wertheim博士及其同事分析的幾宗疫情中，只有俄羅斯流感被證明是例外。導致新冠肺炎的病毒—SARS-CoV-2—則不是。

研究人員發現，SARS-CoV-2 在感染人類之前並沒有發生任何異常變化。它像其他蝙蝠冠狀病毒一樣，在蝙蝠間傳播的過程中不斷發生變異；只有在病毒出現在人類身上之後，才出現了顯著的變化。不到一年，全新的變種病毒就不斷湧現，這些變異使其能夠完美地適應人類。

這項新研究為新冠病毒起源的持續爭論增添了新的內容。美國國立衛生研究院院長Jay Bhattacharya博士在1月接受《紐約時報》採訪時斷言，SARS-CoV-2 源自於實驗室。他說: 「我認為，如果只看科學證據，我會說這是肯定的」。

一些支持實驗室洩漏起源論的專家指出，SARS-CoV-2 從疫情爆發之初就充份预備好在人群中傳播。去年11月，美國疾病管制與預防中心前主任Robert Redfield博士聲稱，中國軍方發展了SARS-CoV-2病毒作為吸入式疫苗。Redfield博士在一次播客採訪中說道: 「我認為這一切都是設計出來的」。

但上個月，世界衛生組織指派的一個專家小組對新冠病毒的起源進行了調查，最終得出結論：SARS-CoV-2病毒起源於蝙蝠，然後蝙蝠將其傳播給了武漢一家市場出售的動物。

科學家指出:「大多數經過同行評審的科學證據都支持這個假設」。

Wertheim博士曾參與那個收集一部分曾經過同儕審查的科學證據。他表示，這項新研究為病毒起源於動物的觀點提供了更多證據。

如果SARS-CoV-2病毒是在實驗室中培育的，那麼它的變異模式應該類似於俄羅斯流感病毒。然而，Wertheim博士及其同事發現，它的變異模式與他們研究的五宗自然發生的疫情相吻合。

Wertheim博士表示，新冠病毒的出現似乎純粹是運氣不佳。其前身病毒在適應感染蝙蝠的過程中，最終卻意外地具備了在人類中引發大流行的能力。 Wertheim博士說: 「它巧合地非常擅長成為一種人類病毒」。

並未參與這項新研究的格拉斯哥大學的病毒學家David Robertson，他表示，這項研究不僅為新冠病毒，也為所有人畜共通病毒 - 即從動物傳播給人類的病毒 - 提供了新的見解。 “這是理解人畜共患風險的關鍵，”他說道:“病毒可以在自然界中傳播，而無需進行適應性改造就能成功感染或傳播給人類。”

Wertheim博士表示，如果這種情況普遍存在於多種人畜共通病毒中，那麼未來我們可能會面臨更多疫情。 他說道:「讓我們陷入困境的，是我們不知道的事」，「它們就在那裡，隨時準備爆發」。

So, a new study finds that Covid is pretty ordinary. Scientists have compared seven viral outbreaks that occurred in recent decades. For the most part, the researchers find that the outbreaks have not been preceded by any unusual genetic changes in the viruses. In all but one case, in 1977, the viruses circulated in animals and gained the ability to spread to and among people. Covid appears to have arisen from some really bad luck of human. Apparently, we can expect more pandemics in the future.