得克萨斯州州长丹·帕特里克（Dat Patrick）在69岁时相对容易受到COVID-19惨案的破坏，于周一提出要作出最终牺牲。他说，他将“全力以赴”，以解除国家的封锁，并使美国人重返工作岗位。第二天，唐纳德·特朗普总统宣布约会。特朗普周二在福克斯新闻市政厅说：“我很想让这个国家开放，只是想在复活节之前去。” 第二天，特朗普宣布德克萨斯州为“重大灾难”。
在第一批COVID-19病例袭击纽约市并威胁要淹没其医院之际，公共卫生官员对终止限制的讨论感到震惊。但是，何时以及如何取消国家就地庇护战略的根本问题是合理的。疾病控制中心的顾问星期三说，预计美国的死亡人数将在3周左右达到高峰。那会发生什么呢？有什么计划？
如果可以安全，尽快地完成锁定，则有充分的理由解除锁定。对经济的严重破坏影响了贫困率和失业率，并加剧了压力，所有这些都会给公共健康，特别是那些以薪水为生的人造成重大损失。破坏持续的时间越长，经济回升的难度就越大。在某个时候，锁定可能会适得其反，但难以量化。
另一方面，取消限制得太早或太突然，几乎肯定会引发感染的第二次激增，可能与第一次一样致命。当太多的病人一次生病时，医院不堪重负，许多最病的病人得不到治疗，这在意大利已经发生，可能很快就会在纽约市发生。停止COVID-19是不可能的-它具有很高的传播性，当足够高的人群免疫时，成群免疫需要时间来发展。
知道何时解除锁定是很困难的，部分原因是对COVID-19病毒知之甚少，这种病毒仅在几个月前才首次在人类中出现，而且在美国的测试还远远不够，因此，决策者正在努力斯坦福大学的流行病学家约翰·约阿尼迪斯（John Ioannidis）说，天黑了。他质疑美国封锁的某些方面是否弊大于利。例如，关闭学校，将孩子们带回家与父母同住，可能会增加人口中年龄较大，更弱势群体的感染率。他在上周的《 StatNews》上写道：“由于缺乏真正的流行病数据，我们不知道这种观点是辉煌还是灾难性的。”
缺乏知识是卫生官员对特朗普总统的复活节时间表如此震惊的原因之一。流行病学家戴维·卡兹（David Katz）在《纽约时报》的一篇专栏文章中指出，人口中最弱势的成员（60岁以下，没有健康状况的人）可能会早日恢复工作，并可能发展成群免疫力，保护弱势群体。（不过，尚不清楚患者对这种病毒产生免疫力。）不过，卡茨在推特上发文说，“任意“返工”期限是危险的愚蠢行为。”
世界卫生组织正在为各国起草准则，以解除封锁。世卫组织传染病科学和技术咨询小组负责人，流行病学家大卫·海曼说，任何使该国重返工作的计划都必须得到数据的支持。他的小组正在研究在亚洲和欧洲采取的措施，并计划在一两周内发布报告。（该小组目前未获得美国的支持）尽管许多亚洲国家在2002年经历了SARS爆发，但他们具备更好的诊断测试能力以应对COVID-19危机，但它们在过渡过程中也面临挑战某种常态。海曼说：“大多数国家没有退出战略。”
尽管报告尚未完成，但海曼分享了一些要点。他说，一旦封锁使第一波爆发变得平淡无奇，其想法是考虑缓慢释放经济的某些部门，同时评估病毒对放松限制措施的反应。如果感染急剧上升，卫生系统将不得不跳下它们，以免疾病再次爆发。他说，在采取任何措施之前，必须进行风险评估。如果说办公室要重新开放，那么公共汽车和火车上以及饮水机周围可能发生多少病毒交换？在某些情况下，该活动是否会引发第二次高峰？
他说，这种计划的一个基本要素是一个监视系统，它可以使卫生官员一次准确地了解有多少人被感染。（从Amazon仓库中COVID-19感染的增加中可以明显看出这一点。）多产的测试是关键。仅仅知道某个城市或州有多少人具有COVID-19，还不够。卫生官员需要知道携带病毒的人口百分比，以及它们在城市和县之间的分布情况。这种数据要求对人群进行随机检验，这是民意测验者对公众舆论进行抽样的方式。它必须能够在地方一级区分爆发，以识别出感染源，然后再扩大。
海曼和其他专家将密切关注未来几周中国的情况。中国已经使用严厉的社会距离措施来遏制第一波COVID-19感染。但是最近它解除了对行业的一些限制。现在知道它会产生什么影响还为时过早，但是它应该为美国和欧洲提供有用的信息。
重返工作策略的另一个要素是弄清楚如何保护最容易感染COVID-19的老年人和有潜在健康问题的人。如果可以将病例数保持在较低水平，这将为最需要的人腾出医院资源。最终，如果事实证明人们在患病后对COVID-19病毒产生了免疫力，则疫苗和牛群的免疫力可能会使新的感染率降低。
有了正确的政策，不久以后至少有些人将能够重返工作岗位而不会危及Dan Patrick的生命。
AMID CORONAVIRUS, EXPERTS QUESTION WHEN IT'S SAFE TO GO BACK TO WORK, LOCKDOWN HAD NO 'EXIT STRATEGY'
Texas Lt. Gov. Dan Patrick, who at 69 would be relatively vulnerable to the ravages of COVID-19, offered on Monday to make the ultimate sacrifice. He said he'd be "all in" for lifting the nation's lockdown and getting Americans back to work. The next day, President Donald Trump floated a date. "I would love to have the country opened up and just raring to go by Easter," Trump said on Fox News town hall on Tuesday. The next day, Trump declared Texas a "major disaster."
Public health officials were aghast at talk of ending restrictions just as the first wave of COVID-19 cases was hitting New York City, threatening to overwhelm its hospitals. But the fundamental question of when and how to lift the nation's shelter-in-place strategy is legitimate. Deaths in the U.S. are expected to peak in about 3 weeks, a consultant to the Centers for Disease Control said Wednesday. What happens then? What's the plan?
There are good reasons to lift the lockdown, provided it can be done safely, as soon as possible. The severe disruption to the economy affects rates of poverty and unemployment and adds to stress, all of which exacts a toll on public health, particularly on people who live paycheck to paycheck. The longer that disruption goes on, the more difficult it will be for the economy to climb back. At some point, a lockdown may become counterproductive—but where that point lies is difficult to quantify.
Lifting restrictions too soon or too abruptly, on the other hand, will almost certainly trigger a second spike in infections, which could be just as deadly as the first. When too many patients fall ill at once, hospitals are overwhelmed and many of the sickest go without treatment, as has been happening in Italy and may happen soon in New York City. Stopping COVID-19 is out of the question—it's too highly transmissible, and herd immunity, when a high enough percentage of the population is immune, takes time to develop.
Knowing when to lift the lockdown is difficult in part because so little is known about the COVID-19 virus, which first arose in humans only a few months ago, and testing is woefully inadequate in the U.S. As a result, policymakers are working in the dark, says John Ioannidis, an epidemiologist at Stanford. He questions whether some aspects of the U.S. lockdowns are doing more harm than good. For instance, school closings, by sending kids home with their parents, might wind up increasing infections among older, more vulnerable members of the population. "In the absence of data on the real course of the epidemic," he wrote in StatNews last week, "we don't know whether this perspective was brilliant or catastrophic."
This lack of knowledge is one reason health officials were so alarmed by President Trump's Easter timetable. Epidemiologist David Katz argued in an op-ed in The New York Times that the least vulnerable members of the population—those under 60 with no health conditions—might be able to go back to work sooner rather than later, and might develop herd immunity that protects the vulnerable. (It's not clear, though, that patients develop immunity to the virus.) Still, Katz tweeted that an "arbitrary 'back to business' deadline is dangerous folly."
The World Health Organization is now drafting guidelines for nations to lift their lockdowns. Any plan to return the nation to work must be supported by data, says epidemiologist David Heymann, head of the WHO's Scientific and Technical Advisory Group for Infectious Hazards. His group is studying measures taken in Asia and Europe and plans to issue a report in a week or two. (The group is currently working with no input from the U.S.) Although many Asian countries, having lived through the SARS outbreak in 2002, were better equipped with diagnostic tests to handle the COVID-19 crisis, they also face a challenge in making the transition to some kind of normalcy. "Most countries don't have an exit strategy," says Heymann.
Although the report isn't yet complete, Heymann shared some of the main points. Once lockdown has blunted the first wave of the outbreak, he says, the idea is to consider unlocking certain sectors of the economy slowly, all the while measuring the virus's response to the loosening of restrictions. If infections rise precipitously, health systems would have to jump on them to avoid a resurgence of the disease. Before taking any measures, he says, a risk assessment would have to be made. If, say, offices are going to reopen, how much virus-swapping is likely to take place on the buses and trains and around the water cooler? And will that activity prompt a second spike in cases?
An essential element of such a plan, he says, is a surveillance system that gives health officials an accurate view of how many people are infected at any one time. (That much is clear from the rise of COVID-19 infections in Amazon warehouses.) Prolific testing is key. It's not enough to know how many people have COVID-19 in a particular city or state; health officials need to know what percentage of the population is carrying the virus, and how they're distributed among cities and counties. That kind of data calls for random testing of populations, the way pollsters sample public opinion. It would have to be able to distinguish outbreaks at a local level to identify pockets of infection before they balloon.
Heymann and other experts will be paying close attention to what happens in China in the weeks ahead. China has already tamped down its first wave of COVID-19 infections, using draconian measures of social distancing. But it recently lifted some restrictions on industry. It's too soon to know what effect it will have, but it should provide useful information for the U.S. and Europe.
Another element to a back-to-work strategy will be figuring out how to protect older people and those with underlying health issues, who are most vulnerable to COVID-19. If the number of cases can be kept at a low simmer, it would free up hospital resources for those who most need it. Eventually, a vaccine and herd immunity—if it turns out that people develop an immunity to the COVID-19 virus after illness—may keep new infections low.
With the right policy, before long at least some people will be able to go back to work without putting Dan Patrick's life in danger.
