COVID-19: How and Why the Virus Spreads Quickly
This is another in our series of coronavirus episodes of Scientific American's Science Talk, posted on March 23, 2020. I'm Steve Mirsky.
In this two-part episode, our contributing editor W. Wayt Gibbs in Washington State—a state hit early and hard by COVID-19—reports on scientists' fast-evolving understanding of this new coronavirus and the probable trajectory of this pandemic.
在这个分为两部分的节目中，我们的特约编辑W. Wayt Gibbs在华盛顿州——新冠肺炎早期重创的州——报道了为何新冠肺炎扩散如此之快以及后续可能发展的轨迹。
Today, in part one, he focuses on why the new coronavirus is spreading so quickly and is so difficult to control.
Check back in tomorrow for part two, when Gibbs looks at computer models that are predicting how long we'll need to shut down large parts of society to prevent hospitals from being overwhelmed. He also looks at how emerging tests for immunity to the virus could pose thorny ethical issues in the months to come.
Wayt recorded this episode on March 22. The first voice you hear: Governor Jay Inslee of Washington.
JI: "It is not rhetorical or hyperbolic when I say that everyone needs to change their behavior, change the way that we live—temporarily—if we are going to prevent significant loss of life for the people we love in the state of Washington. And when I say everyone, I mean, frankly, everyone. Because we all are potential transmitters of this virus, and we all, to some varying degree, are potential victims of this virus."
WWG: That was Governor Jay Inslee, pleading with people in my state on March 20 to stay home and stay away from each other. All around the U.S.—and around the world—governors and mayors and prime ministers are urging, begging—in many places even ordering—their citizens to shelter in place.
But it's not easy to resist our hardwired desires to spend time with our friends, to visit our parents and grandparents, to go to work.
So here in Washington, like in lots of other places, compliance has been—kind of spotty. Traffic on some of the major highways here—a good proxy for human intermingling—is down only about 20 percent or so from normal.
But as scientists learn more about the SARS-CoV-2 virus and the COVID-19 pandemic, it's becoming apparent that we're facing a much more serious situation than most of us thought even a couple weeks ago.
Let me give you one example from here in Washington. On March 10, despite stern official warnings not to gather in groups, 56 people met for an event in Skagit County. All of them were apparently healthy at the time. But 10 days later, 43 of those 56 people have either been confirmed to have COVID-19 or are showing symptoms of the disease. Experts suspect that one or more people in the group was a so-called "supershedder," someone who has yet to show symptoms but is transmitting lots of infectious virus.
In this two-part episode, we'll look at several new research studies and new tests announced this week that may help answer four crucial questions.
Question 1: Can you catch this disease from someone who isn't in the same room as you?
Question 2: Can you catch it from somebody who isn't sick—and is there a way to test for that?
Question 3: What combination of shutdowns and closures will do the most to minimize the number of people who die from the pandemic? And how long will those tough restrictions need to continue?
And question 4: How will each of us know when we're immune and no longer need to worry about catching COVID-19 or giving it to someone else? And what will we do with that information once we have it?