无症状感染者具有传染性吗？大城市输入病例能清零吗？听听钟南山怎么说
10日下午，钟南山院士应中国驻韩国大使邢海明邀请，与韩国疫情防控专家进行了线上交流，就无症状感染者、输入病例以及全球疫情发展趋势发表了自己的看法。
钟南山指出：大部分无症状感染者具有传染性；大城市输入病例清零不现实；全球疫情的走向很大程度取决于人为干预措施。
At the invitation of Chinese Ambassador to South Korea Xing Haiming, China's top respiratory expert Zhong Nanshan and South Korean health experts exchanged experiences in containing the spread of COVID-19 via a webinar on Friday afternoon, with topics including asymptomatic cases, imported cases and the trend of the global pandemic.
大部分无症状感染者具有传染性
钟南山表示，无症状感染者涉及到两类人群：一类是与新冠肺炎确诊患者接触过的人群；另一类是来自疫情严重地区的人群，这类人群被感染后上呼吸道带有病毒。
目前看来，大部分无症状感染者经过一段时间后会发展出症状，这类人群是具有传染性的。
然而，有极少数人新冠病毒核酸检测呈阳性，但在后续追踪过程中一直没有表现出症状，此类人群是否具有传染性目前无法确定。钟南山指出，把这类人群作为具有潜在传染性的对象进行隔离是比较安全的做法。
The asymptomatically infected people actually involve two groups, one comprises people who have come into contact with COVID-19 patients, the other involves travelers from places with severe outbreaks, said Zhong. When they are infected, they have the virus in their upper respiratory tract.
Currently, most of the infected appear to be infectious as many asymptomatic people will develop symptoms over a period of time. However, some preliminary studies show a very small number of people whose nucleic acid test is positive but who don't have any symptoms over a long time. It is unclear whether they are contagious.
"We prefer to treat the asymptomatically infected people as potentially infectious ones and isolate them appropriately. It's safer," said Zhong, adding that the proportion of these cases now is very small.
China has issued a circular on the management of asymptomatic cases of COVID-19 to strengthen the detection, reporting and treatment of such cases.
大城市输入病例清零不现实
“风险肯定是存在的，但是风险不等于现实。” 对于国内输入病例是否会造成疫情大暴发，钟南山表示自己并不悲观。
他说，“如果国内采取严格的监控追踪，一旦发现输入病例就进行隔离，并对接触者进行严密的观察，这样的情况下，不会造成暴发。”
钟南山认为，大城市实现输入病例清零并不现实，未来肯定会有陆续的输入病例出现，但是只要控制在最低水平就可以了。
Zhong added that it's not realistic to clear all imported cases, but they can be kept to a minimum level.
Regarding racist remarks online, Zhong emphasized that the infection does not target at a certain race and there's no racial difference when facing the disease.
"Once infected, people should be treated equally to get medical treatment and isolated. There should not be any racial discrimination."
全球疫情走向很大程度取决于人为干预
关于全球疫情的发展趋势，钟南山表示有两个决定因素：一是疾病自身的发展规律；二是人们对疾病的干预措施，这也是更为重要的一个方面。
目前看来，新冠病毒基因突变后更适应在人体内生存了，所以它的传播能力很强。另外，它的致死率比流感高的多，在一些欧洲国家甚至高达10%，这值得我们引起重视。
钟南山认为，依靠群体免疫造成的牺牲太大了，在疫情迅速发展的当下，抓紧研发并接种疫苗才是更好的选择。另外，他还强调了欧美国家政府抗疫态度对全球疫情走向的重要性，并指出封城令和居家令等措施，人与人之间保持一定距离是关键。
如今，美国每日新增确诊病例高达2万多例，钟南山对此表示担忧并呼吁各国加强合作。他说，“地球上200多个国家和地区，缺哪一个都不行，任何一个国家疫情大范围暴发，全世界都不可能安宁。”
The trend of the global COVID-19 pandemic depends on two aspects. One is the law of the disease itself, and the other is intervention, according to Zhong.
"Now this disease has mutated to be well adapted to survive in the human body," the expert said. It spreads vigorously and has a much higher mortality rate than flu, estimated by the World Health Organization to be 10 times higher.
The law of disease refers to mutation and development rules. For general respiratory diseases, they will decrease in the summer.
And "intervention is a more important aspect," said Zhong.
The high mortality rate of COVID-19, which in some European countries even reached 10 percent, requires rapid development of a vaccine. That's a way of human intervention, while "herd immunity" won't work as it requires a huge sacrifice.
"The state of the pandemic also relies greatly on the attitude of European and American governments," stressed Zhong. "None of the countries on the Earth can stay out of the battle. The whole world cannot be at ease when the outbreak takes place in any one county."
He called for joint cooperation among governments, saying the key to the pandemic is containing and reducing the infection.
剑桥大学官网刊文：新冠病毒存在三个主要变体，分别流行在不同区域