2022.06.03 为什么这次COVID浪潮感觉不同

shiyi18

HEALTH
Why This COVID Wave Feels Different
In the winter, cases shot up and plummeted with unprecedented speed. But something else is going on with this surge.

By Yasmin Tayag
An image of rapid tests rotating
The Atlantic ; Getty
JUNE 3, 2022
SHARE
In mid-March, I began to notice a theme within my social circle in New York, where I live: COVID—it finally got me! At that point, I didn’t think much of it. Only a few of my friends seemed to be affected, and case counts were still pretty low, all things considered. By April, images of rapid tests bearing the dreaded double bars were popping up all over my Instagram feed. Because cases had been rising slowly but steadily, I dismissed the trend to the back of my mind. Its presence nagged quietly throughout May, when I attended a party at a crowded hotel and hurled myself into a raging mosh pit. As I emerged, sweating, cases were still creeping upward.

Only last week, more than two months later, did cases finally stop rising in New York—but they’ve plateaued more than they’ve fallen back to Earth. If you simply look at the case counts, this surge is not even in the same stratosphere as the peak of Omicron during the winter, but our current numbers are certainly a massive undercount now that rapid tests are everywhere. The same sort of drawn-out wave has unfolded across the Northeast in recent months, and frankly, it’s a little weird: The biggest waves that have struck the region have been tsunamis of infections that come and go, as opposed to the rising tide we’re seeing now. Other parts of the country currently seem poised to follow the Northeast. In the past two weeks, cases have noticeably increased in states such as Arizona, South Carolina, and West Virginia; California’s daily average case count has risen 36 percent. In April, I called the coronavirus’s latest turn an “invisible wave.” Now I’m starting to think of it as the “When will it end?” wave.

Read: Is America in the middle of an invisible wave?

Consider New York City, which by this point has been the epicenter of several waves, including the one we’re dealing with now. When Omicron arrived last fall, cases jumped very quickly as the new, more transmissible variant broke through existing immune defenses and infected lots of people, who spread the virus like wildfire. A combination of factors quickly extinguished the flame: People got boosted, the public-health messaging changed and some people changed their behaviors, and eventually so many had gotten sick that the virus had fewer people to infect. That’s not what seems to be happening now. For one thing, the shape of the curve feels different: From December 2021 to mid-February 2022—about two and a half months—Omicron erected a skyscraper on the charts. Since March, the current wave has drawn just the rising half of what looks to be a modest hill—and, again, the true shape is much taller. Broadly, the same trends have played out elsewhere, too. Now it’s June, and fresh images of rapid-test results are still circulating within my social circle. Why has this wave felt so different?

The major reason, public-health experts told me, is that Americans, on the whole, are more protected against COVID now than they were during previous times when infections have soared. Omicron was a completely new variant when it first hit during the winter, and it swept through a large chunk of the country. “We built a lot of immunity due to so many people getting sick,” Marisa Eisenberg, an epidemiologist at the University of Michigan, told me. So far, that immunity seems to dampen the spread of the two new forms of Omicron that are behind the current, stretched-out wave of cases. “It’s imperfect, but it’s at least some protection,” Joe Gerald, a public-health professor at the University of Arizona, told me. “As we take people out of the susceptible pool, basically the math works against a large and fast outbreak, so it would tend to slow transmission and make the size of the wave smaller.”

Another major factor at play is the onset of warmer weather, especially in colder parts of the country. School’s nearly out, if it isn’t already, and though people are getting together and traveling more, they’re likely doing so outdoors. In other words, even if people are getting infected with new Omicron strains, they’re not able to spread it as efficiently. “These aren’t ideal transmission conditions for this usually winter virus,” Gerald said. Seasonality may also be one reason that cases first rose in the Northeast, given that the “When will it end?” wave began when it was relatively cooler and people were inclined to gather indoors.

RECOMMENDED READING
A photograph of group of Black people dressed in colorful summer celebration clothes in front of a hanging American flag and a two-story building
Eight Books That Explain the South
IMANI PERRY
A group of troops
At Work, Expertise Is Falling Out of Favor
JERRY USEEM

SPONSOR CONTENT
Meet the Forester Taking a Stand For the Trees
BOUNTY
Read: COVID sure looks seasonal now

The UCLA epidemiologist Tim Brewer said he’s confident that COVID is settling into similar seasonal patterns as illnesses such as the flu and the cold. We’ve seen smaller waves before outside of the winter months, he pointed out. “What’s going on right now is very similar to what happened if you look back at 2020, around June through July. It had this gradual rise in cases and then things kind of leveled off for a while. Hopefully [soon] they’ll level off.” That being said, what we’re seeing now is not identical to earlier stages of the pandemic: Reported cases are much, much higher now versus in summer 2020, and that’s before you account for all the missed infections right now. Also the onset of the summer 2020 wave was not as maddeningly slow as this one has been.

Meanwhile, reported cases are continuing to climb in other regions, namely the South and Southwest. That raises the uncomfortable, frustrating possibility that we’ll be stuck in this wave for quite some time. But then again, even that is hard to know right now, especially as our view of basic pandemic numbers is so murky. “What makes it difficult to understand how a new wave might play out is that we’re still struggling to understand what the size of our susceptible population is, how many people have truly been infected, and how quickly immunity wanes from both vaccination and prior infection,” Gerald said. Eventually, as we learn more about this virus, we might get better at predicting its next turn. But for now, “there’s also going to be weirdo surges that happen whenever they happen,” Eisenberg added.


There’s no sugarcoating it: The “When will it end?” wave is frustrating. We’re entering our third pandemic summer, and yet again cases are high enough that activities such as indoor dining and weddings can come with a real fear of getting sick. But that pattern of slow and steady spread has benefits as well. It’s exactly what we need to prevent our health-care system from getting overwhelmed—with all the side effects of delayed procedures and hospital burnout that comes along with that. Some 25,000 Americans are currently hospitalized with COVID, compared with more than 150,000 at the height of Omicron. There’s a reason “flatten the curve” became an early pandemic slogan—by drawing out infections, we’re helping to ensure that hospitals have space for us when we need it, whether that’s for COVID or any other reason.

But we shouldn’t get too comfortable. This winter could be bad once again—the Biden administration predicts that we’ll see 100 million new cases during the fall and winter, and a new variant could still worsen that outlook. Such a dire situation is not inevitable, though. If anything, the “When will it end?” wave is a reminder that dramatic, all-consuming surges are not necessarily our destiny. Slowing this virus down, whether that’s through vaccinations or ventilation upgrades—or, in this case, the fortunate coincidence of immunity and weather—can go a long way. “The more we interfere with the ability of this virus to replicate and transmit, the fewer the cases will be, and the less we interfere with its ability to replicate and transmit, the more cases there will be,” Brewer said. “It’s just as simple as that.”

Yasmin Tayag is a science editor and writer. She was previously the lead editor of the Medium Coronavirus Blog.



健康
为什么这次COVID浪潮感觉不同
在冬季，病例以前所未有的速度激增和骤降。但是，这股浪潮中发生了其他事情。

雅斯敏-塔亚格报道
一张快速测试旋转的图片
大西洋报》；盖蒂
2022年6月3日

3月中旬，我开始注意到我在纽约的社交圈中的一个主题，我住在那里。COVID--它终于抓住了我! 当时，我并没有多想。我的朋友中似乎只有少数人受到影响，而且考虑到所有情况，病例数仍然相当低。到了4月，带有可怕的双杠的快速测试图片在我的Instagram上到处出现。由于病例一直在缓慢而稳定地上升，我把这一趋势抛到脑后。它的存在在整个5月悄悄地困扰着我，当时我在一家拥挤的酒店参加了一个聚会，并把自己扔进了一个汹涌的混战坑。当我满头大汗地走出来时，病例仍在不断攀升。

直到上周，两个多月后，纽约的病例才最终停止上升--但它们已经停滞不前，而不是回落到地面。如果你简单地看一下病例数，这股浪潮甚至不在冬季奥米克龙的高峰期的同一平流层，但我们目前的数字肯定是一个巨大的低估，因为现在快速测试已经无处不在。最近几个月，同样的浪潮已经在东北地区展开，坦率地说，这有点奇怪：袭击该地区的最大浪潮是来去匆匆的感染海啸，而不是我们现在看到的上升的浪潮。该国其他地区目前似乎准备效仿东北地区。在过去的两周里，亚利桑那、南卡罗来纳和西弗吉尼亚等州的病例明显增加；加利福尼亚的日平均病例数上升了36%。在4月份，我把冠状病毒的最新转变称为 "无形的浪潮"。现在我开始认为它是 "何时结束？"的浪潮。

阅读：美国正处于一个无形的浪潮中吗？

考虑一下纽约市，此时它已经是几个浪潮的中心，包括我们现在处理的这个。当Omicron在去年秋天到来时，由于新的、更具传播性的变体突破了现有的免疫防御系统，感染了很多人，他们像野火一样传播病毒，因此病例迅速增加。一系列的因素很快扑灭了这股火焰。人们得到了鼓舞，公共卫生信息发生了变化，一些人改变了他们的行为，最终有这么多人得了病，病毒可以感染的人越来越少。现在的情况似乎不是这样。首先，曲线的形状感觉不同。从2021年12月到2022年2月中旬--大约两个半月的时间里，奥米克朗在图表上竖起了一座摩天大楼。自3月以来，目前的波浪只是画出了一个小山的上升部分，而且，真正的形状要高得多。总的来说，同样的趋势在其他地方也有体现。现在是6月，快速测试结果的新鲜图片仍在我的社交圈内流传。为什么这一波感觉如此不同？

公共卫生专家告诉我，主要的原因是，从整体上看，美国人现在对COVID的保护程度比以前感染率高的时候要高。Omicron是一个全新的变体，当它在冬季首次出现时，它席卷了全国的一大片地区。"密歇根大学的流行病学家玛丽莎-艾森伯格（Marisa Eisenberg）告诉我，"由于这么多人生病，我们建立了很多免疫力。到目前为止，这种免疫力似乎抑制了两种新形式的欧米茄的传播，而这两种新形式的欧米茄是目前被拉长的病例浪潮的背后。"亚利桑那大学的公共卫生教授乔-杰拉尔德（Joe Gerald）告诉我："这并不完美，但它至少提供了一些保护。"当我们把人们从易感人群中剔除时，基本上数学上的计算是针对大规模和快速爆发的，所以它将倾向于减缓传播，使浪潮的规模变小。"

另一个起作用的主要因素是天气变暖，特别是在该国较冷的地区。如果还没有放学的话，学校也快放学了，尽管人们正在聚会和旅行，但他们很可能在户外进行。换句话说，即使人们感染了新的欧米茄菌株，他们也不能像以前那样有效地传播它。"对于这种通常是冬季的病毒来说，这些并不是理想的传播条件，"杰拉尔德说。季节性也可能是病例首先在东北地区上升的一个原因，因为 "何时结束？"的浪潮开始时，天气相对凉爽，人们倾向于在室内聚集。

推荐阅读
一张照片：一群黑人穿着五颜六色的夏季庆祝服装，在悬挂的美国国旗和一栋两层楼房前的照片
解释南方的八本书
伊玛尼-佩里
一群军队
在工作中，专业技术正逐渐失宠
JERRY USEEM

赞助内容
认识为树木而战的林务员
布恩提
阅读。COVID现在看起来确实是季节性的

加州大学洛杉矶分校的流行病学家蒂姆-布鲁尔（Tim Brewer）说，他相信COVID正在进入类似于流感和感冒等疾病的季节性模式。他指出，我们以前曾在冬季以外的月份看到过较小的波浪。"现在发生的事情非常类似于如果你回顾一下2020年，大约6月到7月发生的事情。案件逐渐增加，然后事情有一段时间趋于平缓。希望[很快]他们会平息下来。" 话虽如此，我们现在看到的情况与大流行病的早期阶段不尽相同。现在报告的病例要比2020年夏季高得多，而且这还没有考虑到现在所有的错过的感染。另外，2020年夏季的发病率也不像这次那样缓慢得让人抓狂。

同时，其他地区的报告病例正在继续攀升，即南部和西南部。这提出了一种令人不舒服的、令人沮丧的可能性，即我们将在这一波中停留相当长的一段时间。但话说回来，即使是这样，现在也很难知道，尤其是我们对基本的大流行病数字的看法是如此模糊。"杰拉尔德说："使我们难以理解新一轮疫情可能发生的原因是，我们仍在努力了解我们的易感人群的规模是多少，有多少人真正被感染，以及免疫力从疫苗接种和先前的感染中消失的速度有多快。最终，随着我们对这种病毒有了更多的了解，我们可能会更好地预测它的下一个转变。但是现在，"也会有奇怪的突发事件发生，只要它们发生，"艾森伯格补充说。


这没有什么好掩饰的。"何时结束？"这股浪潮令人沮丧。我们正在进入我们的第三个大流行夏季，而且病例再次高涨，以至于像室内餐饮和婚礼这样的活动可能伴随着对生病的真正恐惧。但是这种缓慢而稳定的传播模式也有好处。这正是我们需要的，以防止我们的卫生保健系统不堪重负--以及随之而来的程序延迟和医院倦怠的所有副作用。目前约有2.5万名美国人因COVID住院，而在Omicron的高峰期，这一数字超过了15万。使曲线变平 "成为早期大流行病的口号是有原因的，通过引出感染，我们帮助确保医院在我们需要的时候有空间，不管是因COVID还是其他原因。

但是，我们不应该太舒服。这个冬天可能会再次变得糟糕--拜登政府预测，我们将在秋冬季节看到1亿个新病例，而新的变体仍可能使这一前景恶化。不过，这样一个可怕的情况并不是不可避免的。如果有的话，"它什么时候结束？"的浪潮提醒我们，戏剧性的、全面的浪潮不一定是我们的命运。减缓这种病毒，无论是通过疫苗接种还是通风设备的升级，或者在这种情况下，免疫力和天气的幸运巧合，都会有很大的帮助。"布鲁尔说："我们越是干扰这种病毒的复制和传播能力，病例就会越少，而我们越是不干扰它的复制和传播能力，病例就会越多。"就是这么简单。"

Yasmin Tayag是一名科学编辑和作家。她曾是Medium冠状病毒博客的主编。