是的，戴口罩有幫助。這是為什么
是的，戴口罩有幫助。這是為什么
Mask wearing has become a topic of fierce debate.
戴口罩已經成為了激烈爭論的話題。
Take, for example, an analysis of 172 studies that looked at various interventions to prevent the transmission of COVID-19, SARS and MERS from an infected person to people close to them. The analysis, which was published in The Lancet on June 1, found that mask wearing significantly reduces the risk of viral transmission.
以一項對172項研究的分析為例，該研究考察了防止COVID-19、SARS和中東呼吸綜合征(MERS)從感染者向其身邊人傳播的各種干預措施。6月1日發(fā)表在《柳葉刀》上的這項分析發(fā)現(xiàn)，戴口罩可以顯著降低病毒傳播的風險。
"What this evidence supports is that, if there is a policy around using face masks in place, it does actually come with a fairly large effect," says study co-author Holger Schünemann, an epidemiologist at McMaster University.
麥克馬斯特大學的流行病學家、研究合著者霍爾格·舒內曼說：“這些證據支持的是，如果有一項關于使用口罩的政策出臺，它確實會產生相當大的效果。”
Now, most of the studies in the analysis looked at face mask use in health care, not community, settings. And they were observational, not the gold standard of science, a randomized controlled trial, which would be "very unethical in a pandemic," says Jeffrey Shaman, an epidemiologist at Columbia University.
現(xiàn)在，大多數分析中的研究關注的是口罩在衛(wèi)生保健中的使用，而不是社區(qū)環(huán)境。而且它們是觀察性的，而不是科學的黃金標準，是隨機對照試驗。哥倫比亞大學的流行病學家詹佛瑞·沙曼說，這種試驗“在大流行中非常不道德”。
Still, he says the fact that there is a benefit from masks is clear.
不過，他說，口罩的好處是顯而易見的。
"I personally think that face masks are a key component of the non-pharmaceutical arsenal we have to combat COVID-19," says Shaman.
“我個人認為，口罩是我們抗擊COVID-19的非藥物武器的一個關鍵組成部分，”沙曼說。
It's understandable if some people remain skeptical. But that changed as it became clear that infected people can spread the coronavirus before they even show symptoms of COVID-19 or even if they never show symptoms.
有些人對此持懷疑態(tài)度是可以理解的。但情況發(fā)生了變化，因為人們清楚地認識到，感染者甚至在出現(xiàn)COVID-19癥狀之前，或者即使從未出現(xiàn)癥狀，也可以傳播冠狀病毒。
Researchers emphasize there are two main reasons to wear masks. There's some evidence of protection for the wearer, but the stronger evidence is that masks protect others from catching an infection from the person wearing the mask. And infected people can spread the virus just by talking.
研究人員強調，戴口罩有兩個主要原因。有一些證據表明口罩對佩戴者有保護作用，但更有力的證據是，口罩可以保護其他人免受戴口罩者的感染。被感染的人可以僅通過交談傳播病毒。
"If you're talking, when things are coming out of your mouth, they're coming out fast," says Linsey Marr, a researcher at Virginia Tech who studies the airborne transmission of viruses. " I think even a low-quality mask can block a lot of those droplets."
弗吉尼亞理工大學研究病毒通過空氣傳播的研究員林夕·馬爾說:“如果你在說話，當東西從你嘴里出來的時候，它們出來的速度很快。”“我認為即使是一個低質量的口罩也能阻擋很多飛沫。”
Marr points to a study published in Nature Medicine in April that looked at people infected with the flu and seasonal coronaviruses. It found that even loose-fitting surgical masks blocked almost all the contagious droplets the wearers breathed out and even also some infectious aerosols — tiny particles that can linger in the air.
馬爾指出，4月份發(fā)表在《自然醫(yī)學》上的一項研究對感染流感和季節(jié)性冠狀病毒的人進行了研究。研究發(fā)現(xiàn)，即使是寬松的醫(yī)用口罩，也能阻擋佩戴者呼出的幾乎所有傳染性飛沫，甚至還能阻擋一些傳染性氣溶膠——能滯留在空氣中的微小顆粒。
