羣體免疫真的靠譜嗎？西班牙新研究提出質疑

通過大部分人口產生免疫力來阻斷病毒傳播的羣體免疫策略，在西方國家中一直被寄予厚望。日前，西班牙的一項大規模研究得出結果稱，從西班牙人口產生新冠病毒抗體的比例來看，羣體免疫恐怕難以實現。

Covid-19 antibodies in Spain’s population “are insufficient to provide herd immunity,” a new study has claimed, despite the country being one of the worst-affected by the pandemic.

儘管西班牙是受疫情衝擊最嚴重的國家之一，但一項新研究稱，西班牙人口的新冠病毒抗體“不足以產生羣體免疫”。

In a peer-reviewed paper published in the Lancet medical journal Monday, researchers from Harvard, MIT and several Spanish institutions analyzed findings from a widescale study on antibody prevalence in Spain.

本週一（7月6日）發表在醫學期刊《柳葉刀》上的同行評審論文中，來自哈佛大學、麻省理工學院和幾個西班牙研究所的研究人員分析了對西班牙抗體普及率進行的一項大規模研究得出的結果。

More than 251,700 cases of coronavirus have been confirmed in Spain, while the virus has killed 28,388 people in the country to date, according to data compiled by Johns Hopkins University. With 607 deaths per million people, Spain has the third-highest number of deaths relative to population in the world, according to Our World in Data.

根據約翰斯·霍普金斯大學編纂的數據，西班牙確診的新冠肺炎病例逾251700例，迄今爲止新冠病毒已導致該國28388人喪生。用數據看世界網站的數據顯示，西班牙每100萬人中就有607人死於新冠肺炎，死亡率排全球第三。

Households all over Spain were invited at random by the research team to take part in the study, which aimed to determine the proportion of the population that had developed antibodies for the coronavirus.

研究團隊隨機邀請西班牙各地的家庭參與這項研究，該研究旨在確定產生新冠病毒抗體的人佔西班牙人口的比例。

A total of 61,075 people agreed to participate in the study, which was carried out between April 27 and May 11. Participants answered a questionnaire on coronavirus symptoms, were given a point-of-care finger prick test, and had the option to donate blood for further laboratory testing (which 51,958 of the people in the study did).

總共有61075人同意參與這項研究，研究於4月27日到5月11日期間進行。參與者要填寫一份關於新冠肺炎症狀的問卷，接受即時手指點刺檢測，並可選擇是否捐血進行進一步的實驗室測試（51958名研究參與者捐了血）。

point-of-care: 即時的

Just 5% of participants presented with antibodies from point-of-care tests, while antibodies were detected in 4.6% of the blood samples.

手指點刺檢測中只有5%的參與者發現了抗體，提交的血液樣本中有4.6%檢測出了抗體。

According to the findings, there was “substantial geographical variability,” with antibodies found in 10% of samples from Madrid but just 3% of those taken from coastal areas.

研究發現，抗體分佈存在着“極大的地理變化性”，馬德里有10%的樣本發現了抗體，而沿海地區只有3%的樣本發現了抗體。

Around a third of those who tested positive for Covid-19 antibodies had been asymptomatic while infected with the virus, the study found.

研究發現，約有三分之一新冠病毒抗體檢測呈陽性的人在感染病毒時無症狀。

Among those who reported having been unwell with symptoms of Covid-19 prior to the study, 16.9% tested positive for antibodies. Meanwhile, 90% of those who had tested positive for the coronavirus more than 14 days before taking part in the study had antibodies detected in their lab-tested blood samples.

那些報告稱在研究前因新冠肺炎症狀而感到不適的人有16.9%檢測出了抗體。與此同時，在參與研究至少14天前新冠病毒檢測呈陽性的人有90%在送交實驗室檢測的血液樣本中發現了抗體。

"Despite the high impact of Covid-19 in Spain, prevalence estimates remain low and are clearly insufficient to provide herd immunity,” the report’s authors said. “This cannot be achieved without accepting the collateral damage of many deaths in the susceptible population and overburdening of health systems. In this situation, social distance measures and efforts to identify and isolate new cases and their contacts are imperative for future epidemic control.”

該報告的作者稱：“儘管新冠病毒對西班牙造成了很大沖擊，但是抗體的普及率依然偏低，顯然不足以產生羣體免疫。要達成羣體免疫，就不得不接受易感人羣大量死亡和讓醫療系統超負荷的附帶損害。在這種情況下，未來的疫情防控中必須實行社交隔離措施，努力發現和隔離新病例及其密切接觸者。”

Herd immunity is achieved when immunity is built among the general population through some exposure to a virus or infection. The strategy has been cited by health officials in Sweden, which controversially did not impose a lockdown.

羣體免疫的理念是，某種程度的接觸或感染病毒，從而讓整個羣體產生抗體。瑞典衛生官員曾引用了這一策略，該國沒有實施封鎖的決定備受爭議。

However, many experts are skeptical about the effectiveness of such an approach, warning that immunity to the coronavirus is not guaranteed after infection or may only last a short while.

然而，許多專家都對這種方式的有效性感到懷疑，並警告稱，感染新冠病毒後不一定會產生免疫力，或者免疫力可能只能延續一小段時間。

Speaking on CNBC’s “Squawk Box Europe” on Monday, Danny Altmann, professor of immunology at Imperial College London, said it was not a “safe bet” to rely on immunity to Covid-19 as a strategy for coping with the pandemic, adding that herd immunity strategies were “probably never going to work.”

帝國理工學院免疫學教授丹尼·阿爾特曼週一在CNBC電視臺的《歐洲之聲》節目上說，依靠新冠病毒免疫力作爲應對疫情的策略“有風險”，並補充道，羣體免疫策略“很可能永遠不會奏效”。

Depending on how contagious an infection is, between 50% and 90% of a population must be immune to achieve herd immunity, according to experts at Johns Hopkins University, who estimate that at least 70% of the population would need to be immune to Covid-19 for herd immunity to be realized.

約翰斯·霍普金斯大學的專家稱，要達到羣體免疫，50%到90%的人口都必須產生免疫力，比例大小取決於病毒的傳染性有多強。專家估計，要實現對新冠病毒的羣體免疫，至少70%的人口必須產生免疫力。

Top White House health advisor Dr. Anthony Fauci speculated last month that if Covid-19 behaved like other coronaviruses, there “likely isn’t going to be a long duration of immunity” from antibodies. Meanwhile, the WHO has stated that it remains unclear whether those who have already caught the virus once will be immune to getting it again.

白宮頂級衛生顧問安東尼·福奇博士上月推測，如果新冠病毒和其他冠狀病毒的行爲模式一樣，那麼抗體帶來的“免疫力應該不會持續很長時間”。與此同時，世界衛生組織指出，尚不清楚曾感染過新冠病毒的人是否能免於再度感染。