群体免疫真的靠谱吗？西班牙新研究提出质疑

通过大部分人口产生免疫力来阻断病毒传播的群体免疫策略，在西方国家中一直被寄予厚望。日前，西班牙的一项大规模研究得出结果称，从西班牙人口产生新冠病毒抗体的比例来看，群体免疫恐怕难以实现。

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.

尽管西班牙是受疫情冲击最严重的国家之一，但一项新研究称，西班牙人口的新冠病毒抗体“不足以产生群体免疫”。

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.

本周一（7月6日）发表在医学期刊《柳叶刀》上的同行评审论文中，来自哈佛大学、麻省理工学院和几个西班牙研究所的研究人员分析了对西班牙抗体普及率进行的一项大规模研究得出的结果。

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.

根据约翰斯·霍普金斯大学编纂的数据，西班牙确诊的新冠肺炎病例逾251700例，迄今为止新冠病毒已导致该国28388人丧生。用数据看世界网站的数据显示，西班牙每100万人中就有607人死于新冠肺炎，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.

研究团队随机邀请西班牙各地的家庭参与这项研究，该研究旨在确定产生新冠病毒抗体的人占西班牙人口的比例。

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).

总共有61075人同意参与这项研究，研究于4月27日到5月11日期间进行。参与者要填写一份关于新冠肺炎症状的问卷，接受即时手指点刺检测，并可选择是否捐血进行进一步的实验室测试（51958名研究参与者捐了血）。

point-of-care: 即时的

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

手指点刺检测中只有5%的参与者发现了抗体，提交的血液样本中有4.6%检测出了抗体。

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.

研究发现，抗体分布存在着“极大的地理变化性”，马德里有10%的样本发现了抗体，而沿海地区只有3%的样本发现了抗体。

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

研究发现，约有三分之一新冠病毒抗体检测呈阳性的人在感染病毒时无症状。

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.

那些报告称在研究前因新冠肺炎症状而感到不适的人有16.9%检测出了抗体。与此同时，在参与研究至少14天前新冠病毒检测呈阳性的人有90%在送交实验室检测的血液样本中发现了抗体。

"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.”

该报告的作者称：“尽管新冠病毒对西班牙造成了很大冲击，但是抗体的普及率依然偏低，显然不足以产生群体免疫。要达成群体免疫，就不得不接受易感人群大量死亡和让医疗系统超负荷的附带损害。在这种情况下，未来的疫情防控中必须实行社交隔离措施，努力发现和隔离新病例及其密切接触者。”

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.

群体免疫的理念是，某种程度的接触或感染病毒，从而让整个群体产生抗体。瑞典卫生官员曾引用了这一策略，该国没有实施封锁的决定备受争议。

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，许多专家都对这种方式的有效性感到怀疑，并警告称，感染新冠病毒后不一定会产生免疫力，或者免疫力可能只能延续一小段时间。

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.”

帝国理工学院免疫学教授丹尼·阿尔特曼周一在CNBC电视台的《欧洲之声》节目上说，依靠新冠病毒免疫力作为应对疫情的策略“有风险”，并补充道，群体免疫策略“很可能永远不会奏效”。

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.

约翰斯·霍普金斯大学的专家称，要达到群体免疫，50%到90%的人口都必须产生免疫力，比例大小取决于病毒的传染性有多强。专家估计，要实现对新冠病毒的群体免疫，至少70%的人口必须产生免疫力。

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.

白宫顶级卫生顾问安东尼·福奇博士上月推测，如果新冠病毒和其他冠状病毒的行为模式一样，那么抗体带来的“免疫力应该不会持续很长时间”。与此同时，世界卫生组织指出，尚不清楚曾感染过新冠病毒的人是否能免于再度感染。