科學家預測：針對新冠肺炎疫情的隔離措施可能要持續到2022年

有科學家在一份分析報告中警告稱，間歇性的隔離措施可能需要持續到2022年。這項報告指出，未來幾年，新冠肺炎疫情可能會卷土重來。

這份發表在《科學》期刊上的研究報告得出結論說，一時的封鎖將不足以控制全球性流行病，如果沒有持續的限制措施，第二次疫情高峰可能會比目前這次更嚴重。該研究的一次場景模擬預測，在沒有疫苗或有效治療方法的情況下，新冠肺炎疫情可能會在2025年再度襲來。

研究報告的合著者之一、哈佛大學流行病學教授馬克·利普斯蒂奇說：“兩個因素會引發傳染病的傳播：被感染者和易感染者。除非群體免疫的人群比我們所知道的大得多……否則，大多數人口都仍是易感染者。認為疫情將在2020年夏天結束的預測不符合我們對于疫情傳播的了解。”

這份研究報告指出，新的療法、疫苗或急救護理能力的提高可以緩解對嚴格隔離措施的需求，但是作者總結道：“如果上述的這些都沒有的話，監控和間歇性的隔離措施可能將持續到2022年。”

研究發現，未來五年的病例總數和所需的隔離水平很大程度上取決于目前總體的感染水平以及被感染者是否都能獲得免疫力，如果獲得了免疫力，這種免疫力可以持續多久。作者警告稱，這些都是很大的未知因素，因此準確預測疫情長期發展態勢是不可能的。

研究報告指出，如果被感染者能獲得永久的免疫力，那么新冠肺炎疫情將會在第一次暴發至少五年后消失。如果人們的免疫力能持續一年左右，就像其他一些冠狀病毒一樣，那么一年一度的暴發周期將是最可能發生的結果。

荷蘭鹿特丹伊拉斯謨大學醫學中心病毒學主任馬里恩·科普曼斯教授說，對于呼吸道病毒而言，完全且永久的免疫并不常見。他的團隊正在研究被感染者的抗體反應。

在這份最新研究報告發布之前，科普曼斯表示：“你能期待的是——希望如此——那些得過新冠肺炎的人（再次被感染時）癥狀會比較輕。”（孫曄供稿）

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.