在许多国家，经过数周或数月的紧张新冠肺炎锁定限制，政府和官员一直在逐步放松规则，使某些部门能够恢复行动和社交互动在某种程度上进行。

Currently, we are still some way from an effective, safe and readily-available疫苗。Infection rateshave also not been as high as one may have expected at the start of the outbreak, even in areas considered “hotspots” like New York, likely in part due to lockdown measures that have prevented soaring case numbers from overwhelming health services. Certainly, no areas have been identified where infection has been as high as the estimated 60 % infection rate required to confer herd immunity, a point that isstill debated。但是，在没有这种情况的情况下，这确实意味着我们仍然缺乏任何形式畜群免疫在全球人口中，许多人容易受到SARS-COV-2感染。

因此，这就提出了接下来会发生什么的问题？是否有第二波感染，我们可以预测这一点，该怎么办？当我们考虑这些观点时，有必要研究中国的状况如何发展。

Coronavirus in Beijing – isolated outbreak or a second wave of infection?

在6月中旬，中国和新西兰都宣布自己“自由冠状病毒”。但是，这种胜利是短暂的，突出了持续谨慎的需求。在新西兰，两名妇女因同情的理由过早地从隔离中释放，后来才测试阳性。

出现了一群案件北京上周，导致重新引入对当地人口的限制。就像武汉的最初爆发一样linked to a food market。布伦丹·雷恩（Brendan Wren），伦敦卫生与热带医学学院微生物发病机理教授“Beijing had previously gone 57 days without a locally-transmitted case of COVID-19 and the latest peak in the number of cases is a real concern.” As more cases continued to emerge (137 over past six days) and it became clear the outbreak was not under control, China took the decision to once again ground hundreds of flights, raise the emergency level and prevent non-essential travel.

Whilst in the case of New Zealand, the source is known and appears to have been contained, the scenario in China is raising concern. Wren continued “It will be important to establish the source of this re-infection, it is likely to be locally-transmitted through human transfer, but given that the origin of the infection was in China we shouldn’t exclude the possibility of the original animal source suspected from food markets being responsible for the latest outbreak. DNA sequencing of the virus from infected individuals should establish a forensic trail to establish the source and reservoir of this re-infection.”

Some initial reports in Chinese local media following human and environmental testing had suggested a link to the import or packaging of salmon. Given what we know about SARS-CoV-2 infectivity, this seems unlikely to be the primary source, and is more feasibly a result of cross-contamination. Speaking at a周一的新闻发布会, Dr Michael Ryan, Head of the World Health Organization’s (WHO) emergencies program, was keen to stress [in relation to a link to salmon] that “I think we need to look at what has happened in this case, I don’t believe it is the primary hypothesis. But it needs to be explored.” He continued “As we’ve seen in many countries, the emergence of new clusters – especially when the origin of the cluster, the driver of the cluster, is not recognized – is always a concern.”

考虑到北京这一新爆发的来源，基思·尼尔，诺丁汉大学传染病流行病学的名誉教授，他评论说：“中国实际发生的事情永远不会真正透明，因此只有知情的猜测是可能的。北京一直在为所有返回的旅行者使用强制执行的隔离。如果人们在14天的隔离结束时进行了测试，并且鉴于没有测试对100％敏感，并且有1000人返回，则受感染的人会/总是会在这些控件中滑落。这是个人或人到人到人的人传播的人；可能像武汉一样专注于市场。鲑鱼作为来源的可能性极不可能 - 鲑鱼如何变得兴奋？鉴于市场上粪便的评论，食物卫生可能很差。”

这种情况是否构成第二波感染或更本地化的事物取决于您如何看待场景。尼尔得出结论：“这不是第二波，而是局部爆发。这确实取决于您如何定义第二波。重新出现将是一个持续的问题，还请注意新西兰随着国际旅行的情况。”无论您的定义如何，很明显，这是一个持续的问题，不会很快消失，警惕和控制措施将仍然是关键的重要性。

对世界其他地区有什么影响？

当我们从世界各地观看时，中国当前的局势应作为警告。汤姆·温菲尔德博士利物浦热带医学学校的高级临床讲师兼荣誉顾问医师说：“北京的Covid-19爆发爆发以提醒您，尽管英国已经经过了第一波Covid-19，但我们仍然留在早期大流行的阶段。”这种情况在全球范围内呼应，一些国家尚未认为达到了第一波案件的顶峰。

温菲尔德继续说：“在感染后有效的疫苗或免疫力的情况下，如果暴露于SARS-COV-2，大多数人口（无论是在英国还是全球）仍处于Covid-19的风险。不可避免地会继续爆发，即使在每天（例如中国）案件数量很少的国家中，也将继续爆发。”

国家和国际回应是关键

诸如废水监测和正在进行测试are likely to be important factors in identifying and “fire-fighting” new incursions as they crop up for the foreseeable future.

“在地区，国家和国际水平上，迅速和协调的反应将是破坏传播并防止病毒进一步传播的关键。这些反应可能包括针对性的测试，追踪和恢复锁定措施，例如社会疏远和旅行限制。还可能将回应专注于受疫情影响的特定热点地区，而不是成为一般的国家政策。”结束了温菲尔德。

As even hard-hit countries like Italy throw open their borders and re-instate tourist activities in the hope of stimulating much needed income, it should be considered at what human cost and do these actions just prolong the problem?

As cases continue to be identified across China, testing is being ramped up and restrictions tightened in the hope of containing further spread. At least with the wealth of research development that has happened since the initial outbreak in Wuhan, scientists, epidemiologists and officials are better armed to tackle the problem.