專家:疫苗未必能阻止新冠疫情擴(kuò)散
頂級(jí)傳染病專家表示,當(dāng)首支新冠疫苗進(jìn)入市場(chǎng)時(shí),世界并不一定會(huì)因此而恢復(fù)“正?!薄?/p>
在醫(yī)學(xué)雜志《柳葉刀》(Lancet)的一篇新文章中,香港大學(xué)的兩名研究人員警告說,即便當(dāng)?shù)谌谂R床試驗(yàn)結(jié)束時(shí),疫苗在阻止新冠病毒傳播方面的有效性仍將打上問號(hào)。
流行病學(xué)家梁卓偉和公共衛(wèi)生病毒學(xué)家裴偉士認(rèn)為,盡管多家疫苗生產(chǎn)商以創(chuàng)紀(jì)錄的速度進(jìn)行了三期臨床試驗(yàn),但目前,科學(xué)家們?cè)谝呙缛绾未偈谷虼罅餍薪Y(jié)束這一問題上,只成功研究了其中的一部分。
他們表示,目前正在接受評(píng)估的內(nèi)容,只是疫苗如何防止那些接種疫苗的人患上新冠肺炎,而不是疫苗如何能夠減少病毒傳播。
文章寫道,這些疫苗對(duì)感染和傳播的影響沒有得到有效的評(píng)估。“即使疫苗被證明在降低疾病的嚴(yán)重程度方面有效,我們也不能就此認(rèn)為它可以將病毒傳播也降低到類似的程度?!?/p>
換句話說,疫苗制造商可以確定疫苗能否保護(hù)被注射者不患病,但不一定能夠確定疫苗能否阻止被接種者將疾病傳染給其他人。因此,即便疫苗最早可能在今年年底上市,也幾乎沒有證據(jù)表明這種疫苗在阻止新冠疫情傳播方面有多有效。
兩位專家表示,考慮到研究中的漏洞,政策制定者和公眾應(yīng)該調(diào)整他們的預(yù)期,關(guān)注新冠疫苗的推出將如何讓世界回到疫情前的“正?!睜顟B(tài)。
美國(guó)公共衛(wèi)生專家最近也在試圖降低公眾對(duì)疫苗有效性的期望。
美國(guó)疾病控制與預(yù)防中心的主任羅伯特?雷德菲爾德在9月17日的國(guó)會(huì)聽證會(huì)上表示:“我甚至可以說,佩戴口罩比接種疫苗更能夠保護(hù)我免受感染——因?yàn)橐呙缈赡軆H有70%的有效性?!?/p>
美國(guó)總統(tǒng)特朗普稱雷德菲爾德的說法是“不正確的”,但是其他傳染病專家支持他的說法。根據(jù)美國(guó)食品和藥品管理局的要求,只要疫苗被證明有50%的有效性,就會(huì)得到批準(zhǔn)。
盡管存在潛在的限制,兩位專家仍然認(rèn)為,當(dāng)疫苗上市時(shí),公眾不應(yīng)該猶豫。
他們寫道,“需要新冠疫苗”來保護(hù)脆弱人群。但疫苗“只是應(yīng)對(duì)疫情的整體公共衛(wèi)生措施中的一種手段,不太可能是許多人所期望的最終解決方案”。(財(cái)富中文網(wǎng))
編譯:楊二一
頂級(jí)傳染病專家表示,當(dāng)首支新冠疫苗進(jìn)入市場(chǎng)時(shí),世界并不一定會(huì)因此而恢復(fù)“正常”。
在醫(yī)學(xué)雜志《柳葉刀》(Lancet)的一篇新文章中,香港大學(xué)的兩名研究人員警告說,即便當(dāng)?shù)谌谂R床試驗(yàn)結(jié)束時(shí),疫苗在阻止新冠病毒傳播方面的有效性仍將打上問號(hào)。
流行病學(xué)家梁卓偉和公共衛(wèi)生病毒學(xué)家裴偉士認(rèn)為,盡管多家疫苗生產(chǎn)商以創(chuàng)紀(jì)錄的速度進(jìn)行了三期臨床試驗(yàn),但目前,科學(xué)家們?cè)谝呙缛绾未偈谷虼罅餍薪Y(jié)束這一問題上,只成功研究了其中的一部分。
他們表示,目前正在接受評(píng)估的內(nèi)容,只是疫苗如何防止那些接種疫苗的人患上新冠肺炎,而不是疫苗如何能夠減少病毒傳播。
文章寫道,這些疫苗對(duì)感染和傳播的影響沒有得到有效的評(píng)估?!凹词挂呙绫蛔C明在降低疾病的嚴(yán)重程度方面有效,我們也不能就此認(rèn)為它可以將病毒傳播也降低到類似的程度?!?/p>
換句話說,疫苗制造商可以確定疫苗能否保護(hù)被注射者不患病,但不一定能夠確定疫苗能否阻止被接種者將疾病傳染給其他人。因此,即便疫苗最早可能在今年年底上市,也幾乎沒有證據(jù)表明這種疫苗在阻止新冠疫情傳播方面有多有效。
兩位專家表示,考慮到研究中的漏洞,政策制定者和公眾應(yīng)該調(diào)整他們的預(yù)期,關(guān)注新冠疫苗的推出將如何讓世界回到疫情前的“正?!睜顟B(tài)。
美國(guó)公共衛(wèi)生專家最近也在試圖降低公眾對(duì)疫苗有效性的期望。
美國(guó)疾病控制與預(yù)防中心的主任羅伯特?雷德菲爾德在9月17日的國(guó)會(huì)聽證會(huì)上表示:“我甚至可以說,佩戴口罩比接種疫苗更能夠保護(hù)我免受感染——因?yàn)橐呙缈赡軆H有70%的有效性?!?/p>
美國(guó)總統(tǒng)特朗普稱雷德菲爾德的說法是“不正確的”,但是其他傳染病專家支持他的說法。根據(jù)美國(guó)食品和藥品管理局的要求,只要疫苗被證明有50%的有效性,就會(huì)得到批準(zhǔn)。
盡管存在潛在的限制,兩位專家仍然認(rèn)為,當(dāng)疫苗上市時(shí),公眾不應(yīng)該猶豫。
他們寫道,“需要新冠疫苗”來保護(hù)脆弱人群。但疫苗“只是應(yīng)對(duì)疫情的整體公共衛(wèi)生措施中的一種手段,不太可能是許多人所期望的最終解決方案”。(財(cái)富中文網(wǎng))
編譯:楊二一
When the first COVID-19 vaccines reach market, the world will not necessarily return to “normal,” say top infectious disease experts.
In a new article for the Lancet medical journal, two University of Hong Kong researchers caution that even at the conclusion of Phase III clinical trials, important questions will remain about how effective vaccines are in stopping viral transmission of COVID-19.
Gabriel Leung, an infectious disease epidemiologist, and Malik Peiris, a public health virologist, argue that even though multiple vaccine makers have reached Phase III clinical trials at a record pace, scientists are currently studying only part of the equation in gauging how a vaccine may help bring an end to the global pandemic.
Currently, they say, vaccines are being evaluated only for how they prevent those receiving the vaccine from developing COVID-19 and not for how a vaccine might be able to reduce viral transmission.
"The impact of these COVID-19 vaccines on infection and thus transmission is not being assessed," they write. "We cannot assume COVID-19 vaccines, even if shown to be effective in reducing severity of disease, will reduce virus transmission to a comparable degree."
In other words, vaccine makers may determine whether a vaccine can protect those injected from getting sick, but not necessarily whether the vaccine stops those inoculated from spreading the disease to others. So even if a vaccine reaches market—which could happen as early as the end of this year—there may be little evidence as to how effective the vaccine is at stopping the spread of COVID-19.
Given this hole in the research, policymakers and the general public should calibrate their expectations in terms of how a COVID-19 vaccine rollout will return the world to a pre-pandemic “normal,” Leung and Peiris say.
U.S. public health experts also have recently tried to dampen public expectations about the effectiveness of a potential vaccine.
"I might even go so far as to say that this face mask is more guaranteed to protect me against COVID-19 than when I take a COVID-19 vaccine, because [the vaccine] may be 70% [effective]," Robert Redfield, director of the Centers for Disease Control and Prevention, said in a congressional hearing on Sept. 17.
U.S. President Donald Trump called Redfield's statement "incorrect," but other infectious disease experts backed up Redfield's claim. The Food and Drug Administration requires only that a COVID-19 vaccine is proved to be 50% effective for those injected to be approved.
Despite potential limitations, Leung and Peiris argue that the general public should not be hesitant to get vaccines when they come to market.
"COVID-19 vaccines are needed" to protect vulnerable populations, Leung and Peiris write. But vaccines are "only one tool in the overall public health response to COVID-19 and unlikely to be the ultimate solution that many expect."