科学家预测：针对新冠肺炎疫情的隔离措施可能要持续到2022年

有科学家在一份分析报告中警告称，间歇性的隔离措施可能需要持续到2022年。这项报告指出，未来几年，新冠肺炎疫情可能会卷土重来。

这份发表在《科学》期刊上的研究报告得出结论说，一时的封锁将不足以控制全球性流行病，如果没有持续的限制措施，第二次疫情高峰可能会比目前这次更严重。该研究的一次场景模拟预测，在没有疫苗或有效治疗方法的情况下，新冠肺炎疫情可能会在2025年再度袭来。

研究报告的合著者之一、哈佛大学流行病学教授马克·利普斯蒂奇说：“两个因素会引发传染病的传播：被感染者和易感染者。除非群体免疫的人群比我们所知道的大得多……否则，大多数人口都仍是易感染者。认为疫情将在2020年夏天结束的预测不符合我们对于疫情传播的了解。”

这份研究报告指出，新的疗法、疫苗或急救护理能力的提高可以缓解对严格隔离措施的需求，但是作者总结道：“如果上述的这些都没有的话，监控和间歇性的隔离措施可能将持续到2022年。”

研究发现，未来五年的病例总数和所需的隔离水平很大程度上取决于目前总体的感染水平以及被感染者是否都能获得免疫力，如果获得了免疫力，这种免疫力可以持续多久。作者警告称，这些都是很大的未知因素，因此准确预测疫情长期发展态势是不可能的。

研究报告指出，如果被感染者能获得永久的免疫力，那么新冠肺炎疫情将会在第一次暴发至少五年后消失。如果人们的免疫力能持续一年左右，就像其他一些冠状病毒一样，那么一年一度的暴发周期将是最可能发生的结果。

荷兰鹿特丹伊拉斯谟大学医学中心病毒学主任马里恩·科普曼斯教授说，对于呼吸道病毒而言，完全且永久的免疫并不常见。他的团队正在研究被感染者的抗体反应。

在这份最新研究报告发布之前，科普曼斯表示：“你能期待的是——希望如此——那些得过新冠肺炎的人（再次被感染时）症状会比较轻。”（孙晔供稿）

Physical distancing measures may need to be in place intermittently until 2022, scientists have warned in an analysis that suggests there could be resurgences of Covid-19 for years to come.

The paper, published in the journal Science, concludes that a onetime lockdown will not be sufficient to bring the pandemic under control and that secondary peaks could be larger than the current one without continued restrictions.One scenario predicted a resurgence could occur as far in the future as 2025 in the absence of a vaccine or effective treatment.

Marc Lipsitch, a professor of epidemiology at Harvard and coauthor of the study, said: “Infections spread when there are two things: infected people and susceptible people. Unless there is some enormously larger amount of herd immunity than we’re aware of … the majority of the population is still susceptible. Predicting the end of the pandemic in the summer of 2020 is not consistent with what we know about the spread of infections.”

New treatments, a vaccine, or increasing critical care capacity could alleviate the need for stringent physical distancing, according to the paper. “But in the absence of these, surveillance and intermittent distancing may need to be maintained into 2022,” the authors conclude.

The overall numbers of cases in the next five years, and the level of distancing required, were found to depend crucially on the overall current levels of infection and whether all those who are infected gain immunity and, if so, for how long. The authors cautioned that these are big unknowns and that a precise prediction of the long-term dynamics is not possible.

If immunity is permanent, Covid-19 could disappear for five or more years after the first outbreak, the paper suggests. If people have immunity for about a year, as is seen for some other circulating coronaviruses, an annual outbreak cycle would be the most likely outcome.

Prof Marion Koopmans, the head of virology at the Erasmus University Medical Centre in Rotterdam, whose team is studying the antibody response of those infected, said complete and permanent protection would be unusual for a respiratory virus.

"What you would expect to see – hope to see – is that people who have had it once, the disease would get milder,” she said before the latest paper was released.