根據(jù)廢水監(jiān)測(cè)和預(yù)測(cè)人員的建模,,美國(guó)的新冠感染率正徘徊在2020年新冠疫情首次爆發(fā)時(shí)的峰值附近,并接近2021年年底的德爾塔疫情峰值,。
這再次表明,,雖然官方的疫情可能已經(jīng)結(jié)束,但真正的疫情遠(yuǎn)未終結(jié),。
除了2020年3月的初始峰值外,,病毒廢水水平與2020年新冠疫情的所有峰值都相差無(wú)幾,而且已經(jīng)超過了2020年3月的峰值,。根據(jù)Biobot Analytics(為美國(guó)聯(lián)邦政府監(jiān)測(cè)相關(guān)數(shù)據(jù))的數(shù)據(jù),,它們僅略低于2021年年底致命的德爾塔疫情峰值,。
領(lǐng)先的新冠病毒建模專家杰伊·韋蘭在上周發(fā)布的一項(xiàng)預(yù)測(cè)得出了同樣的結(jié)論。韋蘭于9月14日估計(jì),,每天有65萬(wàn)美國(guó)人感染新冠病毒,目前每51名美國(guó)人中就有一人感染了新冠病毒,。
韋蘭預(yù)測(cè),,在接下來的一個(gè)半月里,還會(huì)有7%到10%的美國(guó)人被感染,。
Biobot的數(shù)據(jù)和韋蘭的模型都顯示,,美國(guó)的感染病例開始減少。但在預(yù)期的秋冬季節(jié)的激增之前,,病例可能不會(huì)下降太多(如果有下降的話),。
世界衛(wèi)生組織指出令人擔(dān)憂的趨勢(shì)
根據(jù)美國(guó)疾病控制與預(yù)防中心(U.S. Centers for Disease Control and Prevention)提供的最新數(shù)據(jù),除了新冠病毒感染病例外,,住院和死亡人數(shù)還在繼續(xù)上升,。
從8月27日到9月2日(美國(guó)聯(lián)邦衛(wèi)生機(jī)構(gòu)提供數(shù)據(jù)的最新時(shí)期),住院人數(shù)上升了近9%,。從9月3日至9日,,死亡人數(shù)上升了近5%。
世界衛(wèi)生組織(World Health Organization)的新冠疫情技術(shù)負(fù)責(zé)人瑪利亞·范·科霍夫在9月14日的新聞發(fā)布會(huì)上稱,,世界衛(wèi)生組織不斷收到有關(guān)疫情趨勢(shì)的報(bào)告,,包括越來越多的國(guó)家報(bào)告感染、住院和入住重癥監(jiān)護(hù)室的人數(shù)增加,。
她說,,除了早期診斷和獲得護(hù)理之外,接種疫苗還可以預(yù)防重癥和死亡,。世界衛(wèi)生組織的官員鼓勵(lì)那些因感染預(yù)后不良的高風(fēng)險(xiǎn)人群,,例如老年人和免疫免疫力低下的人,盡快接種加強(qiáng)針——即便這些加強(qiáng)針并不是在世界某些地區(qū)(比如美國(guó)和英國(guó))推出的最新XBB疫苗配方,。
官員們表示,,接種任何現(xiàn)有版本的疫苗和加強(qiáng)針“對(duì)于挽救人們的生命仍然至關(guān)重要”。
美國(guó)批準(zhǔn)更新XBB加強(qiáng)針
美國(guó)疾病控制與預(yù)防中心在上周宣布,,所有年滿六個(gè)月及以上的美國(guó)人都有資格接種針對(duì)XBB奧密克戎毒株定制的最新加強(qiáng)針,。
該機(jī)構(gòu)的免疫實(shí)踐咨詢委員會(huì)(Advisory Committee on Immunization Practices)在9月12日以13比1的投票結(jié)果批準(zhǔn)了Moderna、輝瑞(Pfizer)和Novavax為絕大多數(shù)美國(guó)居民提供的更新版疫苗,。此后不久,,聯(lián)邦衛(wèi)生機(jī)構(gòu)宣布接受委員會(huì)的建議,疫苗在上周晚些時(shí)候上市,。
美國(guó)食品與藥品管理局(U.S. Food and Drug Administration)尚未批準(zhǔn)Novavax的新疫苗,,但該機(jī)構(gòu)在9月11日批準(zhǔn)了Moderna和輝瑞的加強(qiáng)針,。
聯(lián)邦衛(wèi)生官員在9月12日的委員會(huì)會(huì)議上說,美國(guó)疾病控制與預(yù)防中心預(yù)計(jì)會(huì)有足夠的加強(qiáng)針供應(yīng),,不需要優(yōu)先考慮為某些人群(例如老年人或免疫力低下的人)接種首批疫苗,。
美國(guó)公共衛(wèi)生協(xié)會(huì)(American Public Health Association)的執(zhí)行主任喬治·本杰明博士在9月12日告訴《財(cái)富》雜志,所有符合條件的人都應(yīng)該盡可能接種新加強(qiáng)針,。
他說:“顯而易見的是,,疫苗在所有年齡段都是安全有效的。高危人群尤其會(huì)從疫苗中受益,?!?/p>
美國(guó)醫(yī)學(xué)協(xié)會(huì)(American Medical Association)于9月12日在提供給《財(cái)富》雜志的一份聲明中表示,它對(duì)委員會(huì)的建議表示贊同,,認(rèn)為更新后的疫苗接種將在未來幾年內(nèi)防止約40萬(wàn)人住院,,并防止4萬(wàn)人死亡。
世界衛(wèi)生組織說:“我們繼續(xù)強(qiáng)烈敦促每個(gè)人及時(shí)接種新冠,、流感和呼吸道合胞病毒疫苗,,以保護(hù)自己和親人免受嚴(yán)重并發(fā)癥、住院和死亡的威脅,?!笔澜缧l(wèi)生組織還補(bǔ)充道,預(yù)計(jì)今年秋冬的感染人數(shù)會(huì)增加,。
新加強(qiáng)針,,瀕臨滅絕的毒株
去年勞動(dòng)節(jié)(Labor Day)前后發(fā)布的更新版奧密克戎加強(qiáng)針是二價(jià)的,同時(shí)針對(duì)奧密克戎和新冠病毒的初始毒株,。今年的加強(qiáng)針是單價(jià)的,,這意味著它們只針對(duì)一種毒株:“海怪”XBB.1.5。這種病毒去年年底到今年年初在美國(guó)和其他地方占主導(dǎo)地位,。
現(xiàn)在,,該毒株幾乎滅絕。根據(jù)美國(guó)疾病控制與預(yù)防中心提供的最新變體數(shù)據(jù),,估計(jì)9月15日五美國(guó)感染病例中只有2.2%是由XBB.1.5病毒引起的,。
雖然最新的疫苗是針對(duì)瀕臨滅絕的奧密克戎病毒,但它們?nèi)匀挥型A(yù)防目前流行的毒株造成的重癥和死亡,,其中絕大多數(shù)是XBB病毒家族的成員,。
約翰斯·霍普金斯大學(xué)(Johns Hopkins)的醫(yī)學(xué)系(Department of Medicine)負(fù)責(zé)數(shù)據(jù)完整性和分析的副主任斯圖爾特·雷博士在9月12日告訴《財(cái)富》雜志,新疫苗配方“與目前流行的EG.5相關(guān)變體高度相似”,。
最近發(fā)布的初步數(shù)據(jù)顯示,,更新后的加強(qiáng)針也應(yīng)該能夠?qū)π碌摹⒏叨茸儺惖膴W密克戎子代“皮羅拉”BA.2.86提供很好的保護(hù)。該變體不是XBB家族的成員,,而是被認(rèn)為是從所謂的“隱形奧密克戎”BA.2進(jìn)化而來的,。
雷說,更新后的疫苗對(duì)皮羅拉病毒的保護(hù)效果不如它對(duì)EG.5和其他XBB變體的保護(hù)效果好,。盡管如此,,能夠?qū)崿F(xiàn)免疫的不僅僅是抗體(由B細(xì)胞在對(duì)感染和接種疫苗作出反應(yīng)時(shí)產(chǎn)生的)。免疫系統(tǒng)中經(jīng)常被遺忘的另一半是T細(xì)胞,,它在保護(hù)人體免受嚴(yán)重疾病的影響,。雖然T細(xì)胞不能夠像B細(xì)胞那樣預(yù)防感染,但它們?nèi)匀挥兄跍p輕BA.2.86感染,、EG.5感染或其他感染的帶來的影響,。
對(duì)棘手的“翻轉(zhuǎn)”突變的擔(dān)憂日益增加
根據(jù)美國(guó)疾病控制與預(yù)防中心發(fā)布的新數(shù)據(jù),,盡管9月15日美國(guó)的“變體湯”基本沒有變化,,但專家們繼續(xù)敲響警鐘,認(rèn)為具有相同但令人擔(dān)憂的突變的變體比例正在上升,。
位于美國(guó)阿肯色州瓊斯伯勒的紐約理工學(xué)院(New York Institute of Technology)的研究助理院長(zhǎng)兼副教授拉杰·拉杰納拉亞南(新冠病毒變體追蹤頂級(jí)專家)在9月15日告訴《財(cái)富》雜志,,過去一個(gè)月里,美國(guó)約93%的新冠病毒序列含有F486P突變,。這種突變位于刺突蛋白上,,通過與人類細(xì)胞更緊密地結(jié)合,增強(qiáng)了病毒的感染能力,。拉杰納拉亞南將其稱為本季的標(biāo)志性突變,。
他說,在同一時(shí)期,,大約一半的美國(guó)基因序列出現(xiàn)了F456L突變,,該突變也出現(xiàn)在刺突蛋白中。這種突變使病毒具有更高的免疫(疫苗接種和先前感染病毒獲得的)逃逸能力,。他補(bǔ)充說,,所有美國(guó)頂級(jí)譜系都有這種突變。
此外,,拉杰納拉亞南補(bǔ)充道,,頂級(jí)譜系也開始攜帶刺突突變L455F,這進(jìn)一步降低了感染難度,。
由于涉及氨基酸變化的復(fù)雜科學(xué)原因,,變體追蹤者將F456L和L455F突變稱為“翻轉(zhuǎn)”突變。專家說,,這兩種突變正在成為本季最令人擔(dān)憂的趨勢(shì)之一,,Biobot追蹤的近20%的廢水樣本中含有這種突變。
專家們說,今年秋冬,,沒有哪個(gè)變體會(huì)比其他變體更有優(yōu)勢(shì),。但“翻轉(zhuǎn)組合”的變體可能會(huì)成為主導(dǎo),并構(gòu)成本季最嚴(yán)重的變體,。
更重要的是,,拉杰納拉亞南說,高度變異的變體“皮羅拉”BA.2.86很可能在某些時(shí)候出現(xiàn)“翻轉(zhuǎn)”,,使其成為更嚴(yán)重的變體,,并有可能讓其實(shí)現(xiàn)更有效的傳播。(財(cái)富中文網(wǎng))
譯者:中慧言-王芳
根據(jù)廢水監(jiān)測(cè)和預(yù)測(cè)人員的建模,,美國(guó)的新冠感染率正徘徊在2020年新冠疫情首次爆發(fā)時(shí)的峰值附近,,并接近2021年年底的德爾塔疫情峰值。
這再次表明,,雖然官方的疫情可能已經(jīng)結(jié)束,,但真正的疫情遠(yuǎn)未終結(jié)。
除了2020年3月的初始峰值外,,病毒廢水水平與2020年新冠疫情的所有峰值都相差無(wú)幾,,而且已經(jīng)超過了2020年3月的峰值。根據(jù)Biobot Analytics(為美國(guó)聯(lián)邦政府監(jiān)測(cè)相關(guān)數(shù)據(jù))的數(shù)據(jù),,它們僅略低于2021年年底致命的德爾塔疫情峰值,。
領(lǐng)先的新冠病毒建模專家杰伊·韋蘭在上周發(fā)布的一項(xiàng)預(yù)測(cè)得出了同樣的結(jié)論。韋蘭于9月14日估計(jì),,每天有65萬(wàn)美國(guó)人感染新冠病毒,,目前每51名美國(guó)人中就有一人感染了新冠病毒。
韋蘭預(yù)測(cè),,在接下來的一個(gè)半月里,,還會(huì)有7%到10%的美國(guó)人被感染。
Biobot的數(shù)據(jù)和韋蘭的模型都顯示,,美國(guó)的感染病例開始減少,。但在預(yù)期的秋冬季節(jié)的激增之前,病例可能不會(huì)下降太多(如果有下降的話),。
世界衛(wèi)生組織指出令人擔(dān)憂的趨勢(shì)
根據(jù)美國(guó)疾病控制與預(yù)防中心(U.S. Centers for Disease Control and Prevention)提供的最新數(shù)據(jù),,除了新冠病毒感染病例外,住院和死亡人數(shù)還在繼續(xù)上升,。
從8月27日到9月2日(美國(guó)聯(lián)邦衛(wèi)生機(jī)構(gòu)提供數(shù)據(jù)的最新時(shí)期),,住院人數(shù)上升了近9%。從9月3日至9日,,死亡人數(shù)上升了近5%,。
世界衛(wèi)生組織(World Health Organization)的新冠疫情技術(shù)負(fù)責(zé)人瑪利亞·范·科霍夫在9月14日的新聞發(fā)布會(huì)上稱,,世界衛(wèi)生組織不斷收到有關(guān)疫情趨勢(shì)的報(bào)告,包括越來越多的國(guó)家報(bào)告感染,、住院和入住重癥監(jiān)護(hù)室的人數(shù)增加,。
她說,除了早期診斷和獲得護(hù)理之外,,接種疫苗還可以預(yù)防重癥和死亡,。世界衛(wèi)生組織的官員鼓勵(lì)那些因感染預(yù)后不良的高風(fēng)險(xiǎn)人群,例如老年人和免疫免疫力低下的人,,盡快接種加強(qiáng)針——即便這些加強(qiáng)針并不是在世界某些地區(qū)(比如美國(guó)和英國(guó))推出的最新XBB疫苗配方,。
官員們表示,接種任何現(xiàn)有版本的疫苗和加強(qiáng)針“對(duì)于挽救人們的生命仍然至關(guān)重要”,。
美國(guó)批準(zhǔn)更新XBB加強(qiáng)針
美國(guó)疾病控制與預(yù)防中心在上周宣布,,所有年滿六個(gè)月及以上的美國(guó)人都有資格接種針對(duì)XBB奧密克戎毒株定制的最新加強(qiáng)針。
該機(jī)構(gòu)的免疫實(shí)踐咨詢委員會(huì)(Advisory Committee on Immunization Practices)在9月12日以13比1的投票結(jié)果批準(zhǔn)了Moderna,、輝瑞(Pfizer)和Novavax為絕大多數(shù)美國(guó)居民提供的更新版疫苗,。此后不久,聯(lián)邦衛(wèi)生機(jī)構(gòu)宣布接受委員會(huì)的建議,,疫苗在上周晚些時(shí)候上市,。
美國(guó)食品與藥品管理局(U.S. Food and Drug Administration)尚未批準(zhǔn)Novavax的新疫苗,,但該機(jī)構(gòu)在9月11日批準(zhǔn)了Moderna和輝瑞的加強(qiáng)針,。
聯(lián)邦衛(wèi)生官員在9月12日的委員會(huì)會(huì)議上說,美國(guó)疾病控制與預(yù)防中心預(yù)計(jì)會(huì)有足夠的加強(qiáng)針供應(yīng),,不需要優(yōu)先考慮為某些人群(例如老年人或免疫力低下的人)接種首批疫苗,。
美國(guó)公共衛(wèi)生協(xié)會(huì)(American Public Health Association)的執(zhí)行主任喬治·本杰明博士在9月12日告訴《財(cái)富》雜志,所有符合條件的人都應(yīng)該盡可能接種新加強(qiáng)針,。
他說:“顯而易見的是,,疫苗在所有年齡段都是安全有效的。高危人群尤其會(huì)從疫苗中受益,?!?/p>
美國(guó)醫(yī)學(xué)協(xié)會(huì)(American Medical Association)于9月12日在提供給《財(cái)富》雜志的一份聲明中表示,它對(duì)委員會(huì)的建議表示贊同,,認(rèn)為更新后的疫苗接種將在未來幾年內(nèi)防止約40萬(wàn)人住院,,并防止4萬(wàn)人死亡。
世界衛(wèi)生組織說:“我們繼續(xù)強(qiáng)烈敦促每個(gè)人及時(shí)接種新冠,、流感和呼吸道合胞病毒疫苗,,以保護(hù)自己和親人免受嚴(yán)重并發(fā)癥、住院和死亡的威脅,?!笔澜缧l(wèi)生組織還補(bǔ)充道,預(yù)計(jì)今年秋冬的感染人數(shù)會(huì)增加。
新加強(qiáng)針,,瀕臨滅絕的毒株
去年勞動(dòng)節(jié)(Labor Day)前后發(fā)布的更新版奧密克戎加強(qiáng)針是二價(jià)的,,同時(shí)針對(duì)奧密克戎和新冠病毒的初始毒株。今年的加強(qiáng)針是單價(jià)的,,這意味著它們只針對(duì)一種毒株:“海怪”XBB.1.5,。這種病毒去年年底到今年年初在美國(guó)和其他地方占主導(dǎo)地位。
現(xiàn)在,,該毒株幾乎滅絕,。根據(jù)美國(guó)疾病控制與預(yù)防中心提供的最新變體數(shù)據(jù),估計(jì)9月15日五美國(guó)感染病例中只有2.2%是由XBB.1.5病毒引起的,。
雖然最新的疫苗是針對(duì)瀕臨滅絕的奧密克戎病毒,,但它們?nèi)匀挥型A(yù)防目前流行的毒株造成的重癥和死亡,其中絕大多數(shù)是XBB病毒家族的成員,。
約翰斯·霍普金斯大學(xué)(Johns Hopkins)的醫(yī)學(xué)系(Department of Medicine)負(fù)責(zé)數(shù)據(jù)完整性和分析的副主任斯圖爾特·雷博士在9月12日告訴《財(cái)富》雜志,,新疫苗配方“與目前流行的EG.5相關(guān)變體高度相似”。
最近發(fā)布的初步數(shù)據(jù)顯示,,更新后的加強(qiáng)針也應(yīng)該能夠?qū)π碌?、高度變異的奧密克戎子代“皮羅拉”BA.2.86提供很好的保護(hù)。該變體不是XBB家族的成員,,而是被認(rèn)為是從所謂的“隱形奧密克戎”BA.2進(jìn)化而來的,。
雷說,更新后的疫苗對(duì)皮羅拉病毒的保護(hù)效果不如它對(duì)EG.5和其他XBB變體的保護(hù)效果好,。盡管如此,,能夠?qū)崿F(xiàn)免疫的不僅僅是抗體(由B細(xì)胞在對(duì)感染和接種疫苗作出反應(yīng)時(shí)產(chǎn)生的)。免疫系統(tǒng)中經(jīng)常被遺忘的另一半是T細(xì)胞,,它在保護(hù)人體免受嚴(yán)重疾病的影響,。雖然T細(xì)胞不能夠像B細(xì)胞那樣預(yù)防感染,但它們?nèi)匀挥兄跍p輕BA.2.86感染,、EG.5感染或其他感染的帶來的影響,。
對(duì)棘手的“翻轉(zhuǎn)”突變的擔(dān)憂日益增加
根據(jù)美國(guó)疾病控制與預(yù)防中心發(fā)布的新數(shù)據(jù),盡管9月15日美國(guó)的“變體湯”基本沒有變化,,但專家們繼續(xù)敲響警鐘,,認(rèn)為具有相同但令人擔(dān)憂的突變的變體比例正在上升。
位于美國(guó)阿肯色州瓊斯伯勒的紐約理工學(xué)院(New York Institute of Technology)的研究助理院長(zhǎng)兼副教授拉杰·拉杰納拉亞南(新冠病毒變體追蹤頂級(jí)專家)在9月15日告訴《財(cái)富》雜志,,過去一個(gè)月里,,美國(guó)約93%的新冠病毒序列含有F486P突變。這種突變位于刺突蛋白上,,通過與人類細(xì)胞更緊密地結(jié)合,,增強(qiáng)了病毒的感染能力,。拉杰納拉亞南將其稱為本季的標(biāo)志性突變。
他說,,在同一時(shí)期,,大約一半的美國(guó)基因序列出現(xiàn)了F456L突變,該突變也出現(xiàn)在刺突蛋白中,。這種突變使病毒具有更高的免疫(疫苗接種和先前感染病毒獲得的)逃逸能力,。他補(bǔ)充說,所有美國(guó)頂級(jí)譜系都有這種突變,。
此外,,拉杰納拉亞南補(bǔ)充道,頂級(jí)譜系也開始攜帶刺突突變L455F,,這進(jìn)一步降低了感染難度,。
由于涉及氨基酸變化的復(fù)雜科學(xué)原因,變體追蹤者將F456L和L455F突變稱為“翻轉(zhuǎn)”突變,。專家說,,這兩種突變正在成為本季最令人擔(dān)憂的趨勢(shì)之一,Biobot追蹤的近20%的廢水樣本中含有這種突變,。
專家們說,,今年秋冬,沒有哪個(gè)變體會(huì)比其他變體更有優(yōu)勢(shì),。但“翻轉(zhuǎn)組合”的變體可能會(huì)成為主導(dǎo),,并構(gòu)成本季最嚴(yán)重的變體。
更重要的是,,拉杰納拉亞南說,,高度變異的變體“皮羅拉”BA.2.86很可能在某些時(shí)候出現(xiàn)“翻轉(zhuǎn)”,,使其成為更嚴(yán)重的變體,,并有可能讓其實(shí)現(xiàn)更有效的傳播。(財(cái)富中文網(wǎng))
譯者:中慧言-王芳
U.S. COVID infections are hovering near levels of the pandemic’s first peak in 2020, and approaching the Delta peak of late 2021, according to wastewater surveillance and modeling by forecasters.
It’s yet another sign that while the official pandemic state may be over, the days of COVID are far from it.
Viral wastewater levels are not far behind all of the pandemic’s 2020 peaks except for one—the initial peak of March 2020, which they’ve already surpassed. And they lag just slightly levels seen during the deadly Delta peak of late 2021, according to Biobot Analytics, which monitors such data for the federal government.
A forecast issued last week by Jay Weiland, a leading COVID modeler, came to the same conclusions. On September 14, Weiland estimated that 650,000 Americans are becoming infected daily, with 1 in 51 Americans currently infected with COVID.
An additional 7% to 10% of the U.S. population will be infected over the next month and a half, Weiland predicted.
Both Biobot data and Wieland’s modeling show U.S. cases beginning to recede. But they may not fall much more, if any, before the anticipated fall and winter surge.
WHO flags concerning trend
Infections aside, COVID hospitalizations and deaths are continuing to rise, according to the latest data available from the U.S. Centers for Disease Control and Prevention.
Hospitalizations rose nearly 9% from Aug. 27 through Sept. 2, the most recent period for which the federal health agency made data available. And deaths rose nearly 5% from Sept. 3-9.
The World Health Organization continues to receive reports on concerning COVID trends, including a growing number of countries reporting an increase in infections, hospitalizations, and ICU admissions, Maria Van Kerkhove, technical lead for COVID-19 response, said at a September 14 news conference.
Vaccination, in addition to early diagnosis and access to care, can prevent severe disease and death, she said. WHO officials encouraged those at high risk for poor outcomes from the virus, like the elderly and immunocompromised, to obtain a booster ASAP—even if it’s not the latest XBB formula being rolled out in some parts of the world.
Vaccinating and boosting with any available version “remains vitally important to saving people’s lives now,” officials said.
U.S. approves updated XBB boosters
All Americans ages 6 months and older are eligible to receive an updated COVID booster tailored to the XBB Omicron strain, the CDC announced at last week.
The agency’s Advisory Committee on Immunization Practices voted 13-1 on September 12 to approve updated jabs from Moderna, Pfizer, and Novavax for the vast majority of U.S. residents. Shortly thereafter, the federal health agency announced that it had accepted the committee’s recommendation, and that vaccines would be available later in the last week.
The U.S. Food and Drug Administration has yet to approve Novavax’s updated formula. But the agency authorized such boosters from Moderna and Pfizer on September 11.
The CDC anticipates having adequate booster supply and shouldn’t need to prioritize certain groups—like the elderly or immunocompromised—for first doses, federal health officials said at the September 12 committee meeting.
All eligible should get the new booster when possible, Dr. Georges Benjamin, executive director of the American Public Health Association, told Fortune on September 12.
“It is clear that the vaccine remains safe and effective at all ages,” he said. “People at high risk will especially benefit from the vaccine.”
In a statement provided to Fortune, the American Medical Association on September 12 said it welcomed the committee’s recommendations, contending that the updated jabs would prevent about 400,000 hospitalizations and 40,000 deaths over the next couple of years.
“We continue to strongly urge everyone to stay up to date on their COVID-19, influenza, and RSV vaccines to protect themselves and their loved ones from severe complications, hospitalization, and death,” the organization said, adding that it expected an increase in infections this fall and winter.
New booster, dying strain
Last year’s updated Omicron boosters, released around Labor Day, were bivalent, tailored to both Omicron and the initial strain of COVID. This year’s boosters are monovalent, meaning they’re tailored to just one strain of the virus: XBB.1.5 “Kraken,” which dominated in the U.S. and elsewhere late last year into early this year.
The strain is now nearly extinct. XBB.1.5 was estimated to be responsible for just 2.2% of U.S. infections on September 15, according to the latest variant data the CDC has made available.
While the newest jabs are tailored to a dying strain of Omicron, they’re still expected to protect against severe disease and death from currently circulating strains, the vast majority of which are members of the XBB viral family.
The formula for the new vaccines “is highly similar to the EG.5-related variants circulating now,” Dr. Stuart Ray, vice chair of medicine for data integrity and analytics at Johns Hopkins’ Department of Medicine, told Fortune on September 12.
Recently released preliminary data shows that refreshed boosters should also offer decent protection against new, highly mutated Omicron spawn “Pirola” BA.2.86. It’s not a member of the XBB family, and is instead thought to have evolved from so-called “stealth Omicron” BA.2.
The updated vaccine’s protection against Pirola won’t be as good as the protection it offers against EG.5 and other XBB variants, Ray said. Still, there is more to immunity than antibodies, produced by B cells in response to infection and vaccination. The other, oft-forgotten half of the immune system, T cells, provides protection against severe disease. While T cells can’t prevent infection like B cells can, they still help soften the blow—of a BA.2.86 infection, EG.5 infection, or otherwise.
Rising concern for troublesome “flip” mutations
While the United States’ “variant soup” remained largely unchanged on September 15, according to new data released by the CDC, experts continued to sound alarm bells about a rising proportion of variants that share the same concerning mutations.
Around 93% of U.S. COVID sequences over the past month contain the mutation F486P, Raj Rajnarayanan—assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., and a top COVID-variant tracker—told Fortune on September 15. The mutation, located on the spike protein, increases the virus’s ability to effectively infect by binding more tightly with human cells. Rajnarayanan refers to it as this season’s signature mutation.
About half of U.S. sequences in over the same period picked up the F456L mutation, also in the spike protein, he said. The mutation makes the virus better at evading immunity from vaccination and prior infection. All top U.S. lineages have this mutation, he added.
What’s more, top lineages are also beginning to pick up the spike mutation L455F, which proffers further ease of infecting cells, Rajnarayanan added.
Variant trackers refer to the F456L and L455F mutations as “flip” mutations, for complex scientific reasons involving amino acid changes. The duo is becoming one of the most concerning trends of the season, experts say, with nearly 20% of wastewater samples tracked by Biobot containing such mutations.
Once again this fall and winter, no one variant may gain a major advantage over others, experts say. But variants with the “flip combo” likely to become dominant and pose this season’s largest issue.
What’s more, it’s likely that highly mutated variant “Pirola” BA.2.86 picks up “flip” at some point, Rajnarayanan said, making it more of an issue—and potentially granting it the ability to spread more effectively.