研究：新冠病毒抗体可能在数月内消失

就在全球科学家积极研发新冠疫苗的时候，英国的一项研究发现，新冠肺炎患者体内的抗体会在数月内消失，而疫苗提供的抗体可能也会如此，这意味着人们无法通过一次性注射疫苗“一劳永逸”。更糟的是，新冠病毒可能会像感冒一样让人们每年重复感染。

A woman holds a small bottle labeled with a "Vaccine COVID-19" sticker and a medical syringe in this illustration taken April 10, 2020. REUTERS/Dado Ruvic

People who have recovered from Covid-19 may lose their immunity to the disease within months, according to research suggesting the virus could reinfect people year after year, like common colds.

一项研究显示，新冠肺炎患者康复后可能会在数月内失去对新冠病毒的免疫力，该研究指出，新冠病毒可能会和普通感冒一样让人们每年重复被感染。

In the first longitudinal study of its kind, scientists analysed the immune response of more than 90 patients and healthcare workers at Guy’s and St Thomas’ NHS foundation trust and found levels of antibodies that can destroy the virus peaked about three weeks after the onset of symptoms then swiftly declined.

在首个同类型纵向研究中，科学家分析了盖伊和圣托马斯国民健康保险信托基金会的90多名患者和医护人员的免疫反应，发现可以摧毁病毒的抗体水平在症状出现三周后达到高点，然后就迅速下降。

Blood tests revealed that while 60% of people marshalled a “potent” antibody response at the height of their battle with the virus, only 17% retained the same potency three months later. Antibody levels fell as much as 23-fold over the period. In some cases, they became undetectable.

血液检测发现，尽管60%的人在和病毒作斗争时身体产生了“强有力的”抗体反应，但只有17%的人在三个月后还有同样强大的抗体。在此期间抗体水平下降到原来的24分之一。在某些情况下，甚至检测不到抗体。

potent [ˈpoʊtnt]: adj. 有效的；强有力的

Screenshot from Guardian

"People are producing a reasonable antibody response to the virus, but it’s waning over a short period of time and depending on how high your peak is, that determines how long the antibodies are staying around,” said Dr Katie Doores, lead author on the study at King’s College London.

这项研究的首席作者、伦敦国王学院的凯蒂·多萝丝博士说：“人们会对病毒产生足够的抗体反应，但是抗体会在短时间内消退，消退早晚取决于最高点的抗体水平，这决定了抗体能在体内存留多久。”

The immune system has multiple ways to fight the coronavirus but if antibodies are the main line of defence, the findings suggested people could become reinfected in seasonal waves and that vaccines may not protect them for long.

免疫系统有多种方式来抗击新冠病毒，但如果抗体是主要防线，该研究指出人们可能会在季节性疫情中被再次感染，疫苗也可能无法长时间保护他们。

"Infection tends to give you the best-case scenario for an antibody response, so if your infection is giving you antibody levels that wane in two to three months, the vaccine will potentially do the same thing,” said Doores. “People may need boosting and one shot might not be sufficient.”

多萝丝说：“感染通常会让身体产生最强的抗体反应，所以如果感染后的抗体水平在两到三个月后消退，疫苗可能也会如此。人们也许需要加强针，一针可能不够。”

Early results from the University of Oxford have shown that the coronavirus vaccine it is developing produces lower levels of antibodies in macaques than are seen in humans infected with the virus. While the vaccine appeared to protect the animals from serious infection, they still became infected and may have been able to pass on the virus.

牛津大学的早期研究结果显示，牛津正在研发的新冠病毒疫苗在猕猴体内产生的抗体水平比感染新冠病毒的人类体内的抗体水平更低。尽管该疫苗似乎能保护动物免于发展为重症，但是动物依然会被感染，或许还能传播病毒。

macaque [məˈkæk]: n. 猕猴，恒河猴；短尾猿

The King’s College study is the first to have monitored antibody levels in patients and hospital workers for three months after symptoms emerged. The scientists drew on test results from 65 patients and six healthcare workers who tested positive for the virus, and a further 31 staff who volunteered to have regular antibody tests between March and June.

伦敦国王学院的这项研究是首个对患者和医院工作人员在症状出现后进行为期三个月的抗体水平监测的研究。科学家采用的测试结果来自新冠病毒检测呈阳性的65名患者和6名医护工作者，以及自愿在三月到六月间定期进行抗体测试的31名工作人员。

The study, which has been submitted to a journal but has yet to be peer-reviewed, found that antibody levels rose higher and lasted longer in patients who were severe cases. This may be because the patients have more virus and churn out more antibodies to fight the infection.

该研究发现发展成重症的患者体内的抗体能达到更高水平，持续时间也更久。这可能是因为这些患者体内病毒更多，产生了更多抗体来抵御感染。这项研究报告已经提交给期刊但还未经过同行评审。

churn out: 快速大量生产

Prof Jonathan Heeney, a virologist at the University of Cambridge, said the study confirmed a growing body of evidence that immunity to Covid-19 is short-lived. “Most importantly, it puts another nail in the coffin of the dangerous concept of herd immunity,” he said.

剑桥大学的病毒学家乔纳森·希尼教授说，这项研究和日益增多的证据相吻合，证实新冠病毒的免疫反应是短暂的。他说：“最重要的是，它给群体免疫的危险概念再次判了死刑。”

But Prof Arne Akbar, an immunologist at UCL, said antibodies are only part of the story. There is growing evidence, he said, that T cells produced to fight common colds can protect people as well. Those patients who fight the virus with T cells may not need to churn out high levels of antibodies, he added.

然而，伦敦大学学院的免疫学家阿恩·阿克巴教授指出，抗体只是抗击病毒的其中一部分，越来越多的证据显示，抗击普通感冒的T淋巴细胞也能保护人们。他补充道，那些用T淋巴细胞抗击新冠病毒的患者也许不需要产生高水平的抗体。