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輝瑞疫苗對德爾塔有效性顯著下降,接下來該怎么辦?

輝瑞疫苗對德爾塔有效性顯著下降,接下來該怎么辦?

Sy Mukherjee 2021年08月13日
現在有越來越多的證據表明,隨著時間的推移,像輝瑞和Moderna這樣的mRNA疫苗會失去保護效力。

8月11日,作為首批獲得美國食品與藥品管理局緊急授權的新冠疫苗制造商,輝瑞及其合作伙伴BioNTech的股價雙雙暴跌。原因是,妙佑醫療國際(Mayo Clinic)發布了一項令人沮喪的新研究,從而迫使投資者紛紛質疑輝瑞疫苗在預防冠狀病毒感染,以及保護接種者免受德爾塔(Delta)變異毒株感染方面的有效性究竟還能夠持續多久。

數據顯示,對于“突破性感染”(意指完成疫苗接種超過14天后新冠病毒檢測結果呈陽性),輝瑞疫苗的有效性可能遠不如Moderna疫苗——輝瑞/BioNTech疫苗的有效性為42%,而Moderna疫苗的有效性為76%。輝瑞股價在當天下跌了近4%,德國BioNTech公司的股價下跌了13.76%。但投資者的反應如此緊迫,也從一個側面凸顯了德爾塔毒株浪潮的嚴重性,以及這種在美國市場銷售了整整9個月的開創性疫苗所面臨的不確定性。

這項研究尚未在同行評議的醫學期刊上發表。它提出了一個關鍵問題:對于數百萬接種了兩劑輝瑞疫苗的美國人來說,是否有必要再打一劑輝瑞加強針(無論是目前可用的加強針,還是某種更新版本)來跟上病毒的突變,或者預防再次感染老的冠狀病毒毒株。到2022年春季,根據與美國政府達成的供應協議,輝瑞預計將交付總額達5億劑的新冠疫苗。有鑒于此,如果美國人使用輝瑞公司的產品進行免疫,他們是否應該擔心感染德爾塔變異毒株,或者將病原體傳播給其他人?

簡而言之:現在有越來越多的證據表明,隨著時間的推移,像輝瑞和Moderna這樣的mRNA(即信使核糖核酸)疫苗會失去保護效力,特別是面對德爾塔變異毒株的時候。而輝瑞疫苗的效力下降得尤為厲害。

妙佑醫療國際的研究發現,與今年早些時候相比,在妙佑醫療國際衛生系統(Mayo Clinic Health System)7月接診的病患中,mRNA疫苗預防感染的能力顯著下降——當月,在這家著名醫療機構所處的明尼蘇達州,德爾塔感染病例在本地新增感染病例的占比超過了70%。1月至7月,Moderna疫苗在預防這一人群感染方面的有效性為86%,輝瑞疫苗的有效性為76%。但僅在7月,Moderna和輝瑞疫苗的有效率就分別降至76%和42%。研究人員發現,在明尼蘇達州以外的疫情重災區,比如佛羅里達州,輝瑞疫苗的有效率也出現了類似的下降。(令人稍感欣慰的是,事實證明,Moderna和輝瑞疫苗在預防新冠感染患者必須入院治療方面仍然非常有效,有效性分別為92%和85%。)

這些都是令人擔憂的數字。但有幾點需要注意。首先,考慮到德爾塔感染病例的激增是一種相對較新的現象,我們仍然需要更多的數據來了解這種毒株正在對疫情造成何種影響,以及它對現有的新冠治療方案有何反應等問題。在美國,這些信息的收集面臨一個漫長的滯后期,因為各地信息匯總到美國疾病控制中心數據庫的速度非常緩慢。

另一個原因是,該機構在5月決定停止追蹤那些可能會導致完全接種者出現癥狀,但還沒有因為感染新冠而住院治療或死亡的“突破性感染”病例,這造成了一個信息黑洞。此外,追蹤一種疫苗在較長時間內對任何病毒株的效力有多大,以及它可能喪失多少免疫能力和喪失的速度,往往受困于對實地情況進行實時監測的能力。

但公共衛生專家指出,如果這一趨勢被更多的同行評議研究證實,制藥商和醫療機構就必須得反思他們對抗高傳染性德爾塔變異毒株的方法。潛在的方案包括打加強針、接種為德爾塔這類毒株量身定制的改良疫苗,或者像英國“混打”阿斯利康(AstraZeneca)疫苗和mRNA疫苗那樣嘗試新冠疫苗的不同組合。

在對抗德爾塔這類惡性變異毒株方面,以輝瑞為代表的mRNA疫苗究竟表現如何?隨著這方面的信息不斷浮現,著名醫生、科學家,斯克里普斯研究轉化研究所(Scripps Research Translational Institute)的創始人及所長埃里克?托波爾直言不諱地表達了他的看法。

托波爾在8月11日發推文稱:“現在需要道出真相:在預防有癥狀的德爾塔感染病例方面,mRNA疫苗的保護效力顯著降低。在德爾塔毒株出現前,它的有效性是95%。許多人聲稱其有效性仍然高達80%左右。絕非如此。從所有來源(不包括美國,因為我們沒有這方面的數據)提供的信息來看,預計有效性最多也就是50%至60%。”他還附上了一張親身編撰的表格,逐一列舉mRNA疫苗、強生和阿斯利康疫苗在對抗德爾塔毒株方面的有效率數據。

托波爾接著指出,以色列等高接種率國家一直在密切關注輝瑞的mRNA免疫效果,鑒于這些國家的經歷,他預計美國的數據一旦出爐,肯定會更加糟糕。盡管mRNA疫苗在預防住院治療和死亡方面的成就不可否認,但患病數天乃至數周仍然是一件令人驚恐的事情,對于像免疫力低下這類高危人群來說,這更是一個公共衛生問題。

對于那些擔心輝瑞疫苗對德爾塔毒株無效的人來說,首要的信息是踐行公共安全指導意見,例如在室內有其他人時戴口罩,在擁擠的地方保持社交距離,還要遵循一些常識,比如咳嗽或打噴嚏時捂住嘴,在擁擠悶熱的房間內除了戴口罩之外,還要保持良好通風。如果你還沒有接種疫苗,現在就是最好的時機。大多數人現在都可以選擇接種三種疫苗,即輝瑞、Moderna和強生疫苗(12歲以上人群可接種輝瑞疫苗)。現在實現充分免疫,將為制藥商和政府機構找到推行加強針的最佳方式贏得寶貴的時間。

關于這一點,輝瑞和Moderna表示,其新冠疫苗接種者可能需要再打一劑加強針,接種時間很可能在2021年冬天之前,特別是那些距離完全接種已經過了4、6或9個月的群體,或者新冠重癥高風險人群。這兩家公司正在對其現有疫苗和新型疫苗進行加強針試驗。Moderna報告稱,在已接種人群中,三種不同的實驗性候選加強針都產生了“強有力的”免疫效果。輝瑞和BioNTech宣稱,在接種現有疫苗的第三劑之后,接種者對其他冠狀病毒變種的抗體反應有所增強。他們相信第三劑疫苗將對德爾塔毒株產生類似效果。預計輝瑞將在本月向美國食品與藥品管理局提交第三劑疫苗的使用授權申請,并且已經開始尋求其疫苗獲得全面使用批準。

此外,輝瑞和BioNTech在一份聲明中表示,鑒于mRNA治療方法具有高度可修改性,“只要獲得監管部門批準,他們有信心、有能力在做出決定后大約100天內開發和生產針對德爾塔毒株的定制疫苗。”但我們仍然需要熬過一段時間才能夠知道,疫苗“混打”、保持目前的接種方式,或者打一劑全新的加強針,最終是否會徹底馴服德爾塔變異毒株。(財富中文網)

譯者:任文科

8月11日,作為首批獲得美國食品與藥品管理局緊急授權的新冠疫苗制造商,輝瑞及其合作伙伴BioNTech的股價雙雙暴跌。原因是,妙佑醫療國際(Mayo Clinic)發布了一項令人沮喪的新研究,從而迫使投資者紛紛質疑輝瑞疫苗在預防冠狀病毒感染,以及保護接種者免受德爾塔(Delta)變異毒株感染方面的有效性究竟還能夠持續多久。

數據顯示,對于“突破性感染”(意指完成疫苗接種超過14天后新冠病毒檢測結果呈陽性),輝瑞疫苗的有效性可能遠不如Moderna疫苗——輝瑞/BioNTech疫苗的有效性為42%,而Moderna疫苗的有效性為76%。輝瑞股價在當天下跌了近4%,德國BioNTech公司的股價下跌了13.76%。但投資者的反應如此緊迫,也從一個側面凸顯了德爾塔毒株浪潮的嚴重性,以及這種在美國市場銷售了整整9個月的開創性疫苗所面臨的不確定性。

這項研究尚未在同行評議的醫學期刊上發表。它提出了一個關鍵問題:對于數百萬接種了兩劑輝瑞疫苗的美國人來說,是否有必要再打一劑輝瑞加強針(無論是目前可用的加強針,還是某種更新版本)來跟上病毒的突變,或者預防再次感染老的冠狀病毒毒株。到2022年春季,根據與美國政府達成的供應協議,輝瑞預計將交付總額達5億劑的新冠疫苗。有鑒于此,如果美國人使用輝瑞公司的產品進行免疫,他們是否應該擔心感染德爾塔變異毒株,或者將病原體傳播給其他人?

簡而言之:現在有越來越多的證據表明,隨著時間的推移,像輝瑞和Moderna這樣的mRNA(即信使核糖核酸)疫苗會失去保護效力,特別是面對德爾塔變異毒株的時候。而輝瑞疫苗的效力下降得尤為厲害。

妙佑醫療國際的研究發現,與今年早些時候相比,在妙佑醫療國際衛生系統(Mayo Clinic Health System)7月接診的病患中,mRNA疫苗預防感染的能力顯著下降——當月,在這家著名醫療機構所處的明尼蘇達州,德爾塔感染病例在本地新增感染病例的占比超過了70%。1月至7月,Moderna疫苗在預防這一人群感染方面的有效性為86%,輝瑞疫苗的有效性為76%。但僅在7月,Moderna和輝瑞疫苗的有效率就分別降至76%和42%。研究人員發現,在明尼蘇達州以外的疫情重災區,比如佛羅里達州,輝瑞疫苗的有效率也出現了類似的下降。(令人稍感欣慰的是,事實證明,Moderna和輝瑞疫苗在預防新冠感染患者必須入院治療方面仍然非常有效,有效性分別為92%和85%。)

這些都是令人擔憂的數字。但有幾點需要注意。首先,考慮到德爾塔感染病例的激增是一種相對較新的現象,我們仍然需要更多的數據來了解這種毒株正在對疫情造成何種影響,以及它對現有的新冠治療方案有何反應等問題。在美國,這些信息的收集面臨一個漫長的滯后期,因為各地信息匯總到美國疾病控制中心數據庫的速度非常緩慢。

另一個原因是,該機構在5月決定停止追蹤那些可能會導致完全接種者出現癥狀,但還沒有因為感染新冠而住院治療或死亡的“突破性感染”病例,這造成了一個信息黑洞。此外,追蹤一種疫苗在較長時間內對任何病毒株的效力有多大,以及它可能喪失多少免疫能力和喪失的速度,往往受困于對實地情況進行實時監測的能力。

但公共衛生專家指出,如果這一趨勢被更多的同行評議研究證實,制藥商和醫療機構就必須得反思他們對抗高傳染性德爾塔變異毒株的方法。潛在的方案包括打加強針、接種為德爾塔這類毒株量身定制的改良疫苗,或者像英國“混打”阿斯利康(AstraZeneca)疫苗和mRNA疫苗那樣嘗試新冠疫苗的不同組合。

在對抗德爾塔這類惡性變異毒株方面,以輝瑞為代表的mRNA疫苗究竟表現如何?隨著這方面的信息不斷浮現,著名醫生、科學家,斯克里普斯研究轉化研究所(Scripps Research Translational Institute)的創始人及所長埃里克?托波爾直言不諱地表達了他的看法。

托波爾在8月11日發推文稱:“現在需要道出真相:在預防有癥狀的德爾塔感染病例方面,mRNA疫苗的保護效力顯著降低。在德爾塔毒株出現前,它的有效性是95%。許多人聲稱其有效性仍然高達80%左右。絕非如此。從所有來源(不包括美國,因為我們沒有這方面的數據)提供的信息來看,預計有效性最多也就是50%至60%。”他還附上了一張親身編撰的表格,逐一列舉mRNA疫苗、強生和阿斯利康疫苗在對抗德爾塔毒株方面的有效率數據。

托波爾接著指出,以色列等高接種率國家一直在密切關注輝瑞的mRNA免疫效果,鑒于這些國家的經歷,他預計美國的數據一旦出爐,肯定會更加糟糕。盡管mRNA疫苗在預防住院治療和死亡方面的成就不可否認,但患病數天乃至數周仍然是一件令人驚恐的事情,對于像免疫力低下這類高危人群來說,這更是一個公共衛生問題。

對于那些擔心輝瑞疫苗對德爾塔毒株無效的人來說,首要的信息是踐行公共安全指導意見,例如在室內有其他人時戴口罩,在擁擠的地方保持社交距離,還要遵循一些常識,比如咳嗽或打噴嚏時捂住嘴,在擁擠悶熱的房間內除了戴口罩之外,還要保持良好通風。如果你還沒有接種疫苗,現在就是最好的時機。大多數人現在都可以選擇接種三種疫苗,即輝瑞、Moderna和強生疫苗(12歲以上人群可接種輝瑞疫苗)。現在實現充分免疫,將為制藥商和政府機構找到推行加強針的最佳方式贏得寶貴的時間。

關于這一點,輝瑞和Moderna表示,其新冠疫苗接種者可能需要再打一劑加強針,接種時間很可能在2021年冬天之前,特別是那些距離完全接種已經過了4、6或9個月的群體,或者新冠重癥高風險人群。這兩家公司正在對其現有疫苗和新型疫苗進行加強針試驗。Moderna報告稱,在已接種人群中,三種不同的實驗性候選加強針都產生了“強有力的”免疫效果。輝瑞和BioNTech宣稱,在接種現有疫苗的第三劑之后,接種者對其他冠狀病毒變種的抗體反應有所增強。他們相信第三劑疫苗將對德爾塔毒株產生類似效果。預計輝瑞將在本月向美國食品與藥品管理局提交第三劑疫苗的使用授權申請,并且已經開始尋求其疫苗獲得全面使用批準。

此外,輝瑞和BioNTech在一份聲明中表示,鑒于mRNA治療方法具有高度可修改性,“只要獲得監管部門批準,他們有信心、有能力在做出決定后大約100天內開發和生產針對德爾塔毒株的定制疫苗。”但我們仍然需要熬過一段時間才能夠知道,疫苗“混打”、保持目前的接種方式,或者打一劑全新的加強針,最終是否會徹底馴服德爾塔變異毒株。(財富中文網)

譯者:任文科

On August 11, Pfizer and partner BioNTech, makers of the United States’ first Food and Drug Administration (FDA) emergency authorized COVID vaccine, saw their share prices plummet as discouraging new research from the Mayo Clinic forced investors to question how long the Pfizer vaccine remains effective at preventing coronavirus infections and protecting those who are vaccinated from getting sick with a Delta variant case.

Pfizer’s shot may be significantly less effective than Moderna’s against breakthrough infections (42% efficacy for Pfizer/BioNTech versus 76% for Moderna), according to the data, and Pfizer stock ended the day down nearly 4% while Germany’s BioNTech slipped 13.76%. But the urgency of the investor reaction underscores the gravity of the Delta wave and uncertainty surrounding a pioneering vaccine that's been on the U.S. market for exactly nine months.

One key issue raised by the study, which has yet to be published in a peer-reviewed medical journal, for the millions of Americans who received two doses of Pfizer’s treatment is whether or not a Pfizer booster dose—either of the currently available jab or a new and updated version—is necessary to keep up with mutations or prevent COVID-19 reinfection from older coronavirus strains. Given that Pfizer expects to have delivered 500 million doses of its COVID vaccine under supply agreements with the U.S. government by the spring of 2022, should Americans be worried about catching a nasty case of the Delta variant or spreading the pathogen to others if they're immunized with Pfizer's product?

In short: There is now mounting evidence that mRNA-based vaccines such as Pfizer's and Moderna's lose potency over time and especially against the Delta variant, and that the Pfizer vaccine's efficacy drop is significantly more dramatic. The Mayo Clinic study noted a wide shortfall in the mRNA vaccines' ability to prevent infections among patients using the Mayo Clinic Health System for the month of July, when Delta variant cases made up more than 70% of new local infections in its home state of Minnesota, compared with earlier in the year. Between January and July, Moderna's jab was 86% effective at preventing infection in this population while Pfizer's was 76% effective. But for July alone, those numbers fell to 76% for Moderna and 42% for Pfizer, and the researchers observed similar drops for the Pfizer shot outside of Minnesota in states with high COVID counts such as Florida. (On a brighter note, both the Moderna and Pfizer vaccines still proved highly effective at preventing the need for COVID infection-related hospitalization at 92% and 85% efficacy, respectively.)

Those are concerning figures. But it's important to note several caveats. For one, we still need more data on how the Delta variant is shaping the pandemic and interacting with available COVID treatments given that mutation's surge is still relatively new. Collecting this information has a long lag time in the U.S. as local information trickles up to the Centers for Disease Control (CDC) database, and the agency's decision in May to stop tracking breakthrough infections that may cause symptoms but not coronavirus-related hospitalization or death among the fully vaccinated has created an information black hole. Furthermore, tracking how strong a vaccine is against any viral strain over an extended period, and how much immunizing power it may lose and how quickly, is inherently handicapped by having to monitor how the situation plays out on the ground in real time.

But public health experts note that if this trend continues to hold true in more peer-reviewed research, drugmakers and medical institutions will have to rethink their approach to fighting the highly infectious Delta variant, potentially through boosters, modified vaccines specifically tailored toward strains like Delta, or by trying different combinations of COVID vaccines as the U.K. has done with AstraZeneca's shot in concert with an mRNA-based vaccine.

Prominent physician-scientist and Scripps Research Translational Institute founder and director Eric Topol didn't mince words about the steady drip of new information on mRNA jabs such as Pfizer's and how they fare against this vicious variant.

"There needs to be truth-telling about the reduced protection of mRNA vaccines vs symptomatic Delta infections. It was 95% pre-Delta. Many are claiming it's still ~80%. It isn't. 50-60% is best estimate from all sources (not US, since we don't have the data)," wrote Topol in a tweet on August 11, attaching a table he compiled of the available efficacy data on mRNA vaccines and the Johnson & Johnson and AstraZeneca jabs when it comes to fighting the Delta strain.

Topol goes on to say he expects the numbers in the U.S., once more of them come out, to be even worse given the experiences of more vaccinated countries like Israel, which are keeping close tabs on how strong Pfizer's mRNA immunization remains over time. While the prevention of hospitalization and death is still an undeniable win, the prospect of getting sick for a few days or weeks is still cumbersome and a public health concern for high-risk individuals such as the immunocompromised.

The overarching message for those worried about their Pfizer vaccine being ineffective against the Delta variant is to practice public safety guidelines such as wearing masks around others indoors and maintaining distance in crowded areas, as well as commonsense practices like covering your mouth if you cough or sneeze and keeping stuffy, crowded rooms well ventilated on top of masking. And if you haven't been vaccinated yet, there's no time like the present. The three COVID shots from Pfizer, Moderna, and Johnson & Johnson are all available to most of the public (including for those 12 years and older for the Pfizer vaccine), and getting fully immunized now would buy precious time as drugmakers and government agencies figure out the best way to proceed with boosters.

On that note, Pfizer and Moderna have stated that their COVID vaccines will likely require booster doses down the line, possibly before winter 2021, and especially for people who are four, six, or nine months out from when they became fully vaccinated or have high risk for serious COVID illness. The companies are conducting booster trials of both their existing vaccines and new types, with Moderna reporting "robust" immunization from three separate, experimental booster candidates among those who had already been vaccinated. Pfizer and BioNTech have touted increased antibody response against other coronavirus variants after a third dose of their existing vaccine and believe they will see similar effects against Delta. Pfizer is expected to request FDA authorization for a third dose this month and has already applied for full approval of its vaccine.

Furthermore, Pfizer/BioNTech said in a statement they expect to be able to "develop and produce a tailor-made vaccine against that [Delta] variant in approximately 100 days after a decision to do so, subject to regulatory approval" given the highly modifiable nature of mRNA-based treatments. But we're still a ways from knowing whether the mix-and-match shots approach, the stay-the-course-on-current-jabs method, or a new kind of booster shot entirely will ultimately tame the COVID Delta variant.

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