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關于新冠變種JN.1,你需要知道這些信息

ERIN PRATER
2023-12-25

世衛組織最新“需要留意的變異株”JN.1,導致個別國家廢水中的新冠病毒含量創歷史新高。

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在印度孟買,一名老師正在畫海報,以提高人們對迅速傳播的JN.1病毒的意識。這種病毒正在印度喀拉拉邦、泰米爾納德邦和果阿邦等地傳播。世界衛生組織在12月19日宣布,JN.1是“需要留意的變異株”,其警告等級僅次于“需要關注的變異株”。圖片來源:INDRANIL ADITYA—NURPHOTO/GETTY IMAGES

世界衛生組織(World Health Organization)正在密切關注一種新出現的新冠病毒變異株。在一些國家,這種變異株導致廢水中的病毒含量達到史上最高水平。

世衛組織上周二將JN.1列為“需要留意的變異株”。JN.1是奧密克戎變異株的亞分支,今年夏天,專家因為它具有異常多的突變而發出警告。這是僅次于“需要關注的變異株”的警告等級。此前,奧密克戎、德爾塔和阿爾法新冠病毒變異株,均屬于“需要關注的變異株”,后來才被世衛組織取消。

JN.1變異株的危險性多高?感染的概率又有多高?它是否會影響你的假期計劃?《財富》雜志采訪的專家認為,你需要知道以下信息。

JN.1到底是什么意思?

從技術角度來說,JN.1是另外一種奧密克戎亞分支。它從BA.2.86新冠變異株進化而來。今年夏天,BA.2.86因為與原始奧密克戎變異株相比出現了大量突變,根據不同計算方法統計突變高達30種甚至更多,因此引起關注。自從2022年奧密克戎在全球傳播以來,BA.2.86曾經是、而且現在依舊是基因方面最特別的新冠病毒變異株。許多專家甚至表示,世界衛生組織有必要以一個新的希臘字母為其命名。

BA.2.86除了有大量突變以外,它還能逃脫免疫,而且更容易感染細胞。新冠變異株跟蹤研究員用一顆小行星的名字,將BA.2.86命名為“Pirola”,以表明他們相信這種新變異株或者其亞分支,最終會獲得一個新希臘字母作為名稱,按照字母表順序可能是Pi或Rho。

BA.2.86并沒有像想象中那樣成為主流病毒,但它在一些地區確實在迅速傳播。早在8月,有專家警告,雖然BA.2.86可能并非一些人想象的“奧密克戎黑天鵝事件”,但它的一個亞分支卻有可能做到。

它就是JN.1。這種變異株的命名雖然聽起來有些奇怪,但事實上并非如此。它是BA.2.86的亞分支之一,主要區別在于一個重要的突變:L455S,這讓它具備了逃脫先前感染和疫苗產生的抗體的能力。L455S讓JN.1“長出了翅膀”,而這是BA.2.86所不具備的能力。

從技術角度來說,JN.1的名稱應該是BA.2.86.1.1。但新冠變異株的命名系統,要求名稱的字母串不超過三組額外數字和句點。因此BA.2.86.1.1“被改為”JN.1。

這就是它名字的由來。

JN.1有哪些癥狀?

現在還無法判斷JN.1的癥狀與奧密克戎的典型癥狀有哪些區別。迄今為止,還沒有太多證據證明JN.1的癥狀不同于奧密克戎,盡管有報道稱腹瀉增加,但不確定這是否與這種變異株有關。

JN.1是否比其他奧密克戎變異株更危險?

現在下結論仍為時尚早。在紐約市等一些地區,住院人數增多。紐約市被視為“風向標”,可以預測美國其他地區的情況。但住院人數增多至少在一定程度上可能是群體免疫力下降的結果。其他變異株毫無疑問導致了住院和死亡。

美國疾病預防控制中心(U.S. Centers for Disease Control and Prevention)最近公開的數據顯示,在美國,從12月9日以來,新冠住院人數緩慢增多,但死亡率保持穩定。

主要新冠病毒建模專家杰伊·維蘭德對《財富》雜志表示,JN.1病毒的免疫逃脫力約為BA.2.86的40至50倍。至于其大幅增強的免疫逃脫力,會對不同群體產生什么影響,我們仍要拭目以待。

新冠疫苗對JN.1是否有效?

是的。疫苗能夠提供良好的保護力,可避免重癥、住院和死亡。

約翰斯·霍普金斯大學(Johns Hopkins)醫學系數據完整性與分析醫學副主任斯圖爾特·雷伊博士對《財富》雜志表示:“如果有人不想感染新冠,希望以更低風險獲得免疫力,幾個月前發布的單價XBB疫苗能夠對JN.1變異株提供強有力的免疫反應?!?/p>

他補充道:“就像之前那些優勢流行變異株一樣,目前尚不確定JN.1是否會導致新冠重癥率或長新冠顯著增加,但我在醫院患者中看到了許多因新冠、合胞病毒和流感引發的呼吸道疾病。因此,在當前呼吸病毒高發季節,應該采取合理的預防措施。”

面對難以控制的JN.1病毒,我是否應該再戴上口罩?

許多專家表示,戴口罩是明智的做法。雷伊建議“在公共場合,尤其是室內,在不影響基本任務的情況下,配戴有效的口罩?!?/p>

他補充道:“而且戴口罩也是一種為臉部保暖的好方法。”

Paxlovid藥物對JN.1是否有效?

是的。但專家警告,如果患者開了Paxlovid藥物,卻因為其令人討厭的金屬味而中途停藥,這可能導致病毒圍繞這種抗病毒藥物進化,最終導致藥物無效。

居家新冠檢測對JN.1是否有效?

是的,但居家監測無論過去還是現在都做不到完全準確。許多人進行檢測的時間過早或過晚。無論過早還是過晚,病毒載量可能都不足以出現陽性檢測結果。專家建議,如果你有癥狀但檢測呈陰性,可以再等兩天重新檢測。

世衛組織宣布JN.1為“需要留意的變異株”。這意味著什么?

12月19日,世衛組織宣布JN.1為“需要留意的變異株”,呼吁各國衛生主管部門保持警惕,并增加基因測序。

加拿大安大略省圭爾夫大學(University of Guelph)生物學教授瑞恩·格里高利對《財富》雜志表示,實際上,對于普通人而言,“這不會帶來任何改變”。一年多以來,格里高利和一批“變異株跟蹤研究人員”設計了新冠變異株的“代號”,以便于向公眾更好地宣傳奧密克戎變異株不斷演變的威脅。

他補充道:“我認為,在某種程度上,他們指出病毒仍在進化,并且依舊值得監控,這是好事。”

JN.1的傳播速度有多快?

由于新冠病毒樣本測序幾乎處于歷史最低水平,因此很難判斷JN.1的傳播速度。雷伊表示,但我們知道,JN.1的傳播速度“似乎將超過全球正在傳播的其他變異株,包括其母系病毒BA.2.86和同代亞分支。”

要評估一種變異株的傳播速度,一種有效的方法是計算其“倍增時間”或者其在特定區域內基因測序數量翻倍的時間。由于基因測序水平較低,難以準確計算新變異株的倍增時間。JN.1的前一代BA. 2.86.1倍增時間約為每兩周一次。維蘭德表示,這遠落后于原始奧密克戎BA.1.1變異株每2.5-3天一次的倍增時間。目前的變異株傳播速度更慢,因此JN.1家族的倍增時間足以令其脫穎而出。

JN.1在哪些國家導致或促使新冠傳播達到創紀錄的水平?

維蘭德表示,目前德國、荷蘭和丹麥廢水中的新冠病毒含量創歷史新高,甚至高于2022年初奧密克戎最高峰時的水平。

專家表示,在美國,除了初始奧密克戎病毒株以外,JN.1可能超過其他所有病毒株。但各國的新冠疫情略有不同甚至有很大區別,這取決于我們已知的許多因素,例如天氣、社交隔離、群體免疫力等,甚至還有一些我們尚不了解的因素。歐洲國家初始奧密克戎疫情的規模小于美國,這可能是這些國家目前JN.1疫情創紀錄的原因。

JN.1從何而來?

科學家們并不能完全確定JN.1及其前身BA.2.86從何而來,這個問題可能永遠都不會有答案。有人認為,BA.2.86可能是在免疫力低下的BA.2患者或者長期感染BA.2的患者體內,經過一年多時間進化而成。BA.2在2022年初被發現,因其在PCR檢測中能夠逃過檢測的能力而被稱為“隱形奧密克戎”。

大多數人的免疫系統能夠在相對較短的時間內擊敗新冠病毒和其他變異株。但免疫系統受損的患者,其感染可能持續幾個月甚至數年,這讓病毒有機會圍繞人體免疫系統不斷進化。在這些情況下,病毒可能“藏匿在”我們意想不到的地方,例如胃腸道系統。此時,在呼吸道系統中進行普通新冠檢測,結果將是陰性。但患者依舊處在被感染狀態,而且可能通過糞便污染傳播病毒。

在長期感染者體內進化的新變異株,很少有機會重新在人群中傳播,而且即使能夠傳播也不太可能馬上超過優勢流行新冠病毒株。為什么呢?變異株在一個宿主體內,沒有必要為了在適者生存的進化過程中獲勝而形成更高的傳播力。但在全球傳播的變異株有幾個月時間,出現新的突變,并增強其傳播能力。

格里高利在今年秋天對《財富》雜志表示,一旦BA.2.86等高度突變的變異株開始大范圍傳播,它就會開始自我完善的過程。他當時表示:“Pirola在宿主體內進化,已經獲得了足夠的立足點,這意味著我們應該要保持警惕?!?/p>

不出所料,BA.2.86繼續進化,最終出現了標志性的刺突蛋白L455S突變,其逃脫先前感染和接種疫苗形成的抗體的能力得到了增強。這就是JN.1能夠迅速傳播而BA.2.86卻沒有形成氣候的原因。

專家表示,原始奧密克戎也是類似的情況。BA.1.1.529是高度突變的原始奧密克戎毒株,它與前身德爾塔病毒幾乎沒有相似之處。但它并沒有快速傳播。在獲得了能令它更快傳播的新突變之后,BA.1.1.529變成了BA.1.1.529.1.1,簡寫為BA.1.1,最終席卷全球。

JN.1未來會走向何方?

簡而言之:無法確定。

JN.1可能像BA.2.86一樣繼續進化,或者像所有新冠毒株一樣消失。變異株之間的競爭是真實的適者生存游戲,它們之間會繼續競爭,通過一種名為趨同進化的平行進化獲得相同或類似的突變。JN.1可能獲得目前還沒有獲得的許多突變,這可能令其后代變得更加棘手。

有專家表示,JN.1可能進化出最新的主要新冠變異株,就像目前所有新出現的主要新冠變異株都從奧密克戎進化而來一樣。換言之,這可能是疫情新時代的起點。

另外,新冠病毒可能再次令全世界措手不及。長期感染看似古老的病毒株的患者體內存在高度突變變異株,可能再次傳播。因此,格里高利認為,公共衛生官員在制定未來計劃時,不能只專注于目前的新冠疫情狀況。因為,有時候,“不可思議的一次性事件可能再次發生”。

變異株跟蹤研究人員是否會給JN.1一個新“代號”,例如對Pirola或Kraken的命名?

格里高利表示,人們針對是否要給JN.1一個單獨的“綽號”進行了“許多討論”。一方面,它與其母系病毒BA.2.86“Pirola”的區別只有一種重大突變。另一方面,它正在以一種Pirola從未有過的勢頭快速傳播。

目前,這些跟蹤者決定不為JN.1重新命名,并將其作為Pirola家族的一員。

他表示:“關鍵不在于某一種變異株,或者它們是否會像最初的奧密克戎一樣引發一波疫情。關鍵是進化譜系的觀念。這符合我們最初的觀點:問題不在于變異株[BA.2.86]本身,”而是它會進化出哪些亞分支——可能是一系列新變異株,例如奧密克戎進化出既有相似之處又有區別的變異株,它們的免疫逃脫力和感染宿主的能力日益增強。(財富中文網)

譯者:劉進龍

審校:汪皓

世界衛生組織(World Health Organization)正在密切關注一種新出現的新冠病毒變異株。在一些國家,這種變異株導致廢水中的病毒含量達到史上最高水平。

世衛組織上周二將JN.1列為“需要留意的變異株”。JN.1是奧密克戎變異株的亞分支,今年夏天,專家因為它具有異常多的突變而發出警告。這是僅次于“需要關注的變異株”的警告等級。此前,奧密克戎、德爾塔和阿爾法新冠病毒變異株,均屬于“需要關注的變異株”,后來才被世衛組織取消。

JN.1變異株的危險性多高?感染的概率又有多高?它是否會影響你的假期計劃?《財富》雜志采訪的專家認為,你需要知道以下信息。

JN.1到底是什么意思?

從技術角度來說,JN.1是另外一種奧密克戎亞分支。它從BA.2.86新冠變異株進化而來。今年夏天,BA.2.86因為與原始奧密克戎變異株相比出現了大量突變,根據不同計算方法統計突變高達30種甚至更多,因此引起關注。自從2022年奧密克戎在全球傳播以來,BA.2.86曾經是、而且現在依舊是基因方面最特別的新冠病毒變異株。許多專家甚至表示,世界衛生組織有必要以一個新的希臘字母為其命名。

BA.2.86除了有大量突變以外,它還能逃脫免疫,而且更容易感染細胞。新冠變異株跟蹤研究員用一顆小行星的名字,將BA.2.86命名為“Pirola”,以表明他們相信這種新變異株或者其亞分支,最終會獲得一個新希臘字母作為名稱,按照字母表順序可能是Pi或Rho。

BA.2.86并沒有像想象中那樣成為主流病毒,但它在一些地區確實在迅速傳播。早在8月,有專家警告,雖然BA.2.86可能并非一些人想象的“奧密克戎黑天鵝事件”,但它的一個亞分支卻有可能做到。

它就是JN.1。這種變異株的命名雖然聽起來有些奇怪,但事實上并非如此。它是BA.2.86的亞分支之一,主要區別在于一個重要的突變:L455S,這讓它具備了逃脫先前感染和疫苗產生的抗體的能力。L455S讓JN.1“長出了翅膀”,而這是BA.2.86所不具備的能力。

從技術角度來說,JN.1的名稱應該是BA.2.86.1.1。但新冠變異株的命名系統,要求名稱的字母串不超過三組額外數字和句點。因此BA.2.86.1.1“被改為”JN.1。

這就是它名字的由來。

JN.1有哪些癥狀?

現在還無法判斷JN.1的癥狀與奧密克戎的典型癥狀有哪些區別。迄今為止,還沒有太多證據證明JN.1的癥狀不同于奧密克戎,盡管有報道稱腹瀉增加,但不確定這是否與這種變異株有關。

JN.1是否比其他奧密克戎變異株更危險?

現在下結論仍為時尚早。在紐約市等一些地區,住院人數增多。紐約市被視為“風向標”,可以預測美國其他地區的情況。但住院人數增多至少在一定程度上可能是群體免疫力下降的結果。其他變異株毫無疑問導致了住院和死亡。

美國疾病預防控制中心(U.S. Centers for Disease Control and Prevention)最近公開的數據顯示,在美國,從12月9日以來,新冠住院人數緩慢增多,但死亡率保持穩定。

主要新冠病毒建模專家杰伊·維蘭德對《財富》雜志表示,JN.1病毒的免疫逃脫力約為BA.2.86的40至50倍。至于其大幅增強的免疫逃脫力,會對不同群體產生什么影響,我們仍要拭目以待。

新冠疫苗對JN.1是否有效?

是的。疫苗能夠提供良好的保護力,可避免重癥、住院和死亡。

約翰斯·霍普金斯大學(Johns Hopkins)醫學系數據完整性與分析醫學副主任斯圖爾特·雷伊博士對《財富》雜志表示:“如果有人不想感染新冠,希望以更低風險獲得免疫力,幾個月前發布的單價XBB疫苗能夠對JN.1變異株提供強有力的免疫反應。”

他補充道:“就像之前那些優勢流行變異株一樣,目前尚不確定JN.1是否會導致新冠重癥率或長新冠顯著增加,但我在醫院患者中看到了許多因新冠、合胞病毒和流感引發的呼吸道疾病。因此,在當前呼吸病毒高發季節,應該采取合理的預防措施?!?/p>

面對難以控制的JN.1病毒,我是否應該再戴上口罩?

許多專家表示,戴口罩是明智的做法。雷伊建議“在公共場合,尤其是室內,在不影響基本任務的情況下,配戴有效的口罩?!?/p>

他補充道:“而且戴口罩也是一種為臉部保暖的好方法。”

Paxlovid藥物對JN.1是否有效?

是的。但專家警告,如果患者開了Paxlovid藥物,卻因為其令人討厭的金屬味而中途停藥,這可能導致病毒圍繞這種抗病毒藥物進化,最終導致藥物無效。

居家新冠檢測對JN.1是否有效?

是的,但居家監測無論過去還是現在都做不到完全準確。許多人進行檢測的時間過早或過晚。無論過早還是過晚,病毒載量可能都不足以出現陽性檢測結果。專家建議,如果你有癥狀但檢測呈陰性,可以再等兩天重新檢測。

世衛組織宣布JN.1為“需要留意的變異株”。這意味著什么?

12月19日,世衛組織宣布JN.1為“需要留意的變異株”,呼吁各國衛生主管部門保持警惕,并增加基因測序。

加拿大安大略省圭爾夫大學(University of Guelph)生物學教授瑞恩·格里高利對《財富》雜志表示,實際上,對于普通人而言,“這不會帶來任何改變”。一年多以來,格里高利和一批“變異株跟蹤研究人員”設計了新冠變異株的“代號”,以便于向公眾更好地宣傳奧密克戎變異株不斷演變的威脅。

他補充道:“我認為,在某種程度上,他們指出病毒仍在進化,并且依舊值得監控,這是好事?!?/p>

JN.1的傳播速度有多快?

由于新冠病毒樣本測序幾乎處于歷史最低水平,因此很難判斷JN.1的傳播速度。雷伊表示,但我們知道,JN.1的傳播速度“似乎將超過全球正在傳播的其他變異株,包括其母系病毒BA.2.86和同代亞分支。”

要評估一種變異株的傳播速度,一種有效的方法是計算其“倍增時間”或者其在特定區域內基因測序數量翻倍的時間。由于基因測序水平較低,難以準確計算新變異株的倍增時間。JN.1的前一代BA. 2.86.1倍增時間約為每兩周一次。維蘭德表示,這遠落后于原始奧密克戎BA.1.1變異株每2.5-3天一次的倍增時間。目前的變異株傳播速度更慢,因此JN.1家族的倍增時間足以令其脫穎而出。

JN.1在哪些國家導致或促使新冠傳播達到創紀錄的水平?

維蘭德表示,目前德國、荷蘭和丹麥廢水中的新冠病毒含量創歷史新高,甚至高于2022年初奧密克戎最高峰時的水平。

專家表示,在美國,除了初始奧密克戎病毒株以外,JN.1可能超過其他所有病毒株。但各國的新冠疫情略有不同甚至有很大區別,這取決于我們已知的許多因素,例如天氣、社交隔離、群體免疫力等,甚至還有一些我們尚不了解的因素。歐洲國家初始奧密克戎疫情的規模小于美國,這可能是這些國家目前JN.1疫情創紀錄的原因。

JN.1從何而來?

科學家們并不能完全確定JN.1及其前身BA.2.86從何而來,這個問題可能永遠都不會有答案。有人認為,BA.2.86可能是在免疫力低下的BA.2患者或者長期感染BA.2的患者體內,經過一年多時間進化而成。BA.2在2022年初被發現,因其在PCR檢測中能夠逃過檢測的能力而被稱為“隱形奧密克戎”。

大多數人的免疫系統能夠在相對較短的時間內擊敗新冠病毒和其他變異株。但免疫系統受損的患者,其感染可能持續幾個月甚至數年,這讓病毒有機會圍繞人體免疫系統不斷進化。在這些情況下,病毒可能“藏匿在”我們意想不到的地方,例如胃腸道系統。此時,在呼吸道系統中進行普通新冠檢測,結果將是陰性。但患者依舊處在被感染狀態,而且可能通過糞便污染傳播病毒。

在長期感染者體內進化的新變異株,很少有機會重新在人群中傳播,而且即使能夠傳播也不太可能馬上超過優勢流行新冠病毒株。為什么呢?變異株在一個宿主體內,沒有必要為了在適者生存的進化過程中獲勝而形成更高的傳播力。但在全球傳播的變異株有幾個月時間,出現新的突變,并增強其傳播能力。

格里高利在今年秋天對《財富》雜志表示,一旦BA.2.86等高度突變的變異株開始大范圍傳播,它就會開始自我完善的過程。他當時表示:“Pirola在宿主體內進化,已經獲得了足夠的立足點,這意味著我們應該要保持警惕。”

不出所料,BA.2.86繼續進化,最終出現了標志性的刺突蛋白L455S突變,其逃脫先前感染和接種疫苗形成的抗體的能力得到了增強。這就是JN.1能夠迅速傳播而BA.2.86卻沒有形成氣候的原因。

專家表示,原始奧密克戎也是類似的情況。BA.1.1.529是高度突變的原始奧密克戎毒株,它與前身德爾塔病毒幾乎沒有相似之處。但它并沒有快速傳播。在獲得了能令它更快傳播的新突變之后,BA.1.1.529變成了BA.1.1.529.1.1,簡寫為BA.1.1,最終席卷全球。

JN.1未來會走向何方?

簡而言之:無法確定。

JN.1可能像BA.2.86一樣繼續進化,或者像所有新冠毒株一樣消失。變異株之間的競爭是真實的適者生存游戲,它們之間會繼續競爭,通過一種名為趨同進化的平行進化獲得相同或類似的突變。JN.1可能獲得目前還沒有獲得的許多突變,這可能令其后代變得更加棘手。

有專家表示,JN.1可能進化出最新的主要新冠變異株,就像目前所有新出現的主要新冠變異株都從奧密克戎進化而來一樣。換言之,這可能是疫情新時代的起點。

另外,新冠病毒可能再次令全世界措手不及。長期感染看似古老的病毒株的患者體內存在高度突變變異株,可能再次傳播。因此,格里高利認為,公共衛生官員在制定未來計劃時,不能只專注于目前的新冠疫情狀況。因為,有時候,“不可思議的一次性事件可能再次發生”。

變異株跟蹤研究人員是否會給JN.1一個新“代號”,例如對Pirola或Kraken的命名?

格里高利表示,人們針對是否要給JN.1一個單獨的“綽號”進行了“許多討論”。一方面,它與其母系病毒BA.2.86“Pirola”的區別只有一種重大突變。另一方面,它正在以一種Pirola從未有過的勢頭快速傳播。

目前,這些跟蹤者決定不為JN.1重新命名,并將其作為Pirola家族的一員。

他表示:“關鍵不在于某一種變異株,或者它們是否會像最初的奧密克戎一樣引發一波疫情。關鍵是進化譜系的觀念。這符合我們最初的觀點:問題不在于變異株[BA.2.86]本身,”而是它會進化出哪些亞分支——可能是一系列新變異株,例如奧密克戎進化出既有相似之處又有區別的變異株,它們的免疫逃脫力和感染宿主的能力日益增強。(財富中文網)

譯者:劉進龍

審校:汪皓

The World Health Organization is keeping an eye on a new COVID variant—one that, in some countries, is sending wastewater levels of the virus skyrocketing to the highest point ever seen.

The global health watchdog on Tuesday promoted JN.1—an Omicron spawn experts flagged this summer for its unusually large number of mutations—to a “variant of interest.” It’s second only in alert level to “variant of concern,” a designation Omicron, Delta, and Alpha had until the organization removed their status.

How dangerous is JN.1, how likely are you to get it, and could it derail your holiday plans? Here’s what you need to know, according to the experts Fortune spoke with.

What in the heck does JN.1 even mean?

JN.1 is yet another Omicron offshoot, technically. It evolved from BA.2.86, a COVID variant that caught the attention of experts this summer because of its large number of mutations compared with the original Omicron: a whopping 30 or more, depending on how you count them. BA.2.86 was—and still is—the most genetically distinct COVID variant to have evolved since Omicron, which made a global splash in 2022. It was so distinct, many experts said, that it warranted a new Greek letter from the World Health Organization.

Along with BA.2.86’s laundry list of mutations came the ability for the virus to evade immunity and infect cells with increasing ease. Variant trackers dubbed BA.2.86 “Pirola”—after an asteroid—as a nod to their belief that the new variant, or one of its offspring, may eventually warrant a new Greek letter: presumably Pi or Rho, next in the alphabet.

BA.2.86 failed to take off in the way it seemed poised to, though it managed to show strong growth in some regions of the world. As early as August, however, experts warned that while BA.2.86 may not be the black swan “Omicron event” some thought it was, one of its descendants could be.

Enter JN.1. While the letters assigned to the strain make it sound like it’s coming from left field, it’s not. It’s BA.2.86 plus one additional major mutation that makes a lot of difference: L455S, which boosts its ability to evade antibodies from prior infection and vaccination. L455S is the reason JN.1 has “sprouted wings,” while BA.2.86 did not.

Technically, JN.1 is BA.2.86.1.1. But the naming system for COVID variants calls for the string of letters to truncate after three additional sets of numbers and periods. So BA.2.86.1.1 “rolled over” to JN.1.

Now you know.

What are the symptoms of JN.1?

It’s too early to tell if the symptoms of JN.1 differ from typical Omicron symptoms. So far, there’s not much evidence that this is the case, though there are reports of increased diarrhea that may or may not be associated with the variant.

Is JN.1 more dangerous than other Omicron variants?

It’s also too early to say. Hospitalizations are rising in some areas like New York City, considered a “bellwether state” that may forecast what’s to come for much of the rest of the country. But rising hospitalizations could be the result of waning population immunity, at least in part. And other variants undoubtedly contribute to hospitalizations and deaths.

In the U.S., COVID hospitalizations were slowly rising as of Dec. 9, while deaths were holding steady, according to the latest data made available by the U.S. Centers for Disease Control and Prevention.

JN.1 looks to be around 40-50 times more immune evasive than BA.2.86, Jay Weiland, a leading COVID modeler, told Fortune. Just how its greatly increased immune evasion will play out in various populations has yet to be seen.

Do COVID vaccines work against JN.1?

Yes. They’re thought to provide good protection against severe illness, hospitalization, and death.

“For those interested in gaining immunity with less risk than COVID-19 illness, the monovalent XBB vaccine released a few months ago provides substantial immune response to the JN.1 variant,” Dr. Stuart Ray, vice chair of medicine for data integrity and analytics at Johns Hopkins’ Department of Medicine, told Fortune.

“Like prior variants that have gained against others, it’s not clear whether JN.1 will result in significantly higher rates of severe COVID-19 or long COVID, but I’m seeing a lot of respiratory illness due to COVID-19, RSV, and influenza in my hospital patients,” he added. “So it makes sense to take reasonable precautions in this respiratory virus season.”

Should I be masking again, with JN.1 on the loose?

It would be wise to, many experts say. Ray recommends “wearing an effective respirator in public spaces, especially indoors, when it doesn’t interfere with essential tasks.”

“Not a bad way to keep your face warm, too,” he added.

Does Paxlovid work against JN.1?

Yes, though experts caution that patients who are prescribed Paxlovid and stop taking the pill midway through, owing to its off-putting metallic taste, could be contributing to the virus’s potential evolution around the antiviral, eventually rendering it ineffective.

Do at-home COVID tests still work with JN.1?

Yes, though they aren’t, and never were, completely accurate. Many people test too early in their infection or too late. At both times, viral loads may not be significant enough to turn the test positive. If you have symptoms but test negative, wait another couple of days and test again, experts recommend.

The WHO just declared JN.1 a ‘variant of interest.’ What does that mean?

When the WHO declared JN.1 a variant of interest Dec. 19, it was calling for vigilance and increased sequencing by health authorities across the globe.

But in a practical sense, and for the average person, “it doesn’t change anything,” Ryan Gregory, a biology professor at the University of Guelph in Ontario, Canada, told Fortune. For over a year, Gregory and a team of “variant trackers” have devised “street names” for COVID variants, in a bid to better communicate the evolving Omicron threat to the public.

“I do think that, in some ways, it’s good that they’re indicating this is still evolving and still worth monitoring,” he added.

Just how fast is JN.1 spreading?

With sequencing of COVID viral samples at a near all-time low, it’s hard to say. We do know, however, that JN.1 “appears to be outcompeting other circulating variants worldwide, including its recent ancestor BA.2.86 and siblings,” Ray said.

A good way to gauge how vast a variant is spreading is its “doubling time,” or the time it takes to double its number of sequences in a particular area. It’s hard to nail down an accurate doubling time on new variants due to low sequencing. JN.1’s immediate predecessor, BA.2.86.1, was doubling about once every two weeks. That pales in comparison to the doubling time of the original Omicron BA.1.1: every 2.5-3 days, according to Weiland. Still, the doubling time of the JN.1 family is enough to make it stand out in the current landscape, comprised of much slower-growing variants.

In what countries is JN.1 causing, or contributing to, a record level of COVID spread?

Countries that are currently seeing all-time highs of COVID in wastewater—higher than even the Omicron spike of early 2022—include Germany, the Netherlands, and Denmark, according to Weiland.

A JN.1 spike in the U.S. could eclipse all other spikes except the initial Omicron spike, experts say. Each country, however, has slightly or even vastly different COVID waves, depending on variables we know of—like weather, social distancing, population immunity, and the like—and even ones we’re not yet aware of. European countries had smaller initial Omicron waves than the U.S. saw, which may be why they’re seeing record-setting JN.1 waves now.

Where did JN.1 come from?

Scientists aren’t exactly sure where JN.1 and its predecessor, BA.2.86, came from and likely never will be. It’s thought that BA.2.86 evolved in the body of an immunocompromised patient—or one with a long-term infection—of BA.2 for over a year. BA.2, if you will remember, hit radars in early 2022 and was known as “stealth Omicron” for its ability to evade detection on PCR tests.

In most people, the immune system defeats the COVID virus, and others, in relatively short order. In those with a compromised immune system, however, infections can remains for months or even years, giving the virus a chance to repeatedly evolve around human immunity. In these cases, the virus may “hole up” somewhere we wouldn’t expect it to, like the GI system. If this happens, typical COVID tests, which involve the respiratory system, will return negative. But the person is still infectious and can spread the virus, potentially through fecal contamination.

New variants that evolve in those with long-term infections are unlikely to immediately out-compete top COVID strains, on the rare occasion that they spill back over into the population. Why? Contained within a single host, a variant has no need to develop increased transmissibility to win an evolutionary survival-of-the-fittest. Globally circulating variants, on the other hand, have had months to pick up new mutations and refine their ability to spread.

Once a highly mutated variant like BA.2.86 escapes into the broader population, it’s likely to begin its own process of refinement, Gregory told Fortune this fall. “The fact that Pirola has gained enough of a foothold to be evolving among hosts now means we need to be wary,” he said at the time.

As predicted, BA.2.86 underwent further evolution, eventually picking up the signature spike protein L455S mutation, which boosts its ability to evade antibodies from prior infection and vaccination. It’s the reason JN.1 has taken off, whereas BA.2.86 did not.

It’s a similar situation to what occurred with the original Omicron, experts say. BA.1.1.529 was the original, highly mutated Omicron, with very little similarities to its predecessor, Delta. It never took off. When it acquired a new mutation that allowed it to transmit faster, it became BA.1.1.529.1.1, shortened to BA.1.1—and that’s what eventually took over the world.

Where is JN.1 going?

In short: Nowhere.

JN.1 will continue to evolve—just as BA.2.86 did—or die, as all strains of COVID do. Variants continually compete in a veritable survival of the fittest, acquiring the same or similar mutations through a form of parallel evolution known as convergent evolution. There are a number of mutations JN.1 doesn’t currently have that it could acquire, potentially making its descendants more troubling than JN.1 itself.

Some experts say that most new major COVID variants could evolve from JN.1, in the way that all new major COVID variants currently evolve from Omicron. In other words, this could be the start of a new era in the pandemic.

On the other hand, COVID could always throw the world another curveball. Highly mutated variants from patients with long-term infections of seemingly ancient strains exist and can always re-enter the population. That’s why public health officials can’t simply focus on the current COVID landscape when planning for the future, Gregory said. Because sometimes, “weird, one-off things come back.”

Will the variant trackers assign JN.1 a new ‘street name’ like Pirola or Kraken?

The group has had “many discussions” as to whether it should give JN.1 its own nickname, Gregory said. On the one hand, only one major mutation separates it from its parent, BA.2.86 “Pirola.” On the other hand, it’s taking off in a way Pirola never did.

For now, the group has decided not to assign a new name to JN.1, and to reference it as a member of the Pirola family.

“What matters is not individual variants and whether they are going to cause a wave as big as the first Omicron. It’s the idea of evolving lineages,” he noted. “It’s consistent with what we said initially: It’s not the variant [BA.2.86], per se, that’s going to be an issue,” but likely what will evolve from it—a whole new line of COVID variants, potentially, in the way Omicron expanded into a family of diverse-yet-similar variants that became increasingly adept at evading immunity and infecting hosts.

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