字幕表 動画を再生する 英語字幕をプリント The alarming thing about the novel coronavirus SARS-CoV-2 is how easily it passes from one person to another. We're still figuring out exactly how it spreads, but it seems like an infected person coughing, or even just exhaling, can shed droplets carrying the virus to another person, and the rule of thumb is that as much as a 6 foot or 1.8 meter radius is everyone's personal “splash zone.” It seems people can also spread the virus even when they're not showing symptoms, further complicating containment. Without countermeasures to break the chain of transmission, the number of cases can balloon exponentially and overwhelm hospitals. To try and stop the virus in its tracks, many places around the world have implemented physical distancing, but another tool that could fight the spread is contact tracing. So, what is contact tracing, how effective is it, and how do we implement it? This probably isn't going to blow anyone's mind, but contact tracing is literally tracing all the people who have been in contact with an infected person. It's the public health equivalent of detective work. Sometimes it's straightforward. Say, a hair stylist is diagnosed with the disease SARS-CoV-2 causes, COVID-19. Their salon likely keeps a list of all the appointments they've had while that stylist was working. A public health worker can then use that list to contact everyone who visited the salon and ask them to monitor their symptoms for two weeks. Some of those people may also be asked to self-quarantine, like if they had prolonged close contact with the stylist, and if, say, an appointment that took hours. Yeah, hair appointments can take hours. You think this just happens naturally? But oftentimes, contact tracing is not so simple. People typically don't keep detailed logs of everyone they've been near all the time, and our memories are imperfect. Even after sorting through calendars and social media posts, contacts can slip through the cracks. Or sometimes, an infected person may have come into contact with hundreds of people and a public health worker might not be able to reach them all. And then, of everyone the public health sleuth does find and contact, a subset of people may just plain not want to comply. Or the original infected person might not want to cooperate and reveal who they've been in contact with. In those cases, public health workers have learned that you catch more flies with honey than vinegar. One of the requirements to be a contact tracer is empathy. People are more likely to respect what is asked of them if they feel respected. The good news is that a contact tracer doesn't have to catch every potential new case to be effective. One epidemiologist estimated that getting 85% of contacts to self quarantine would slow transmission significantly. Still, leveraging technology could help contact tracers cast a bigger net. In countries like Singapore and South Korea there are smartphone apps that track who comes close to each other, and if one of those people gets diagnosed with COVID-19, the others automatically get a message alerting them. Other countries like Germany are in the process of developing similar apps with more privacy protections. To be effective though, one estimate by researchers at Oxford University suggests that at least 60% of the population would need to download the app. Downloading an app wouldn't be necessary though if everyone had the technology automatically. Recently, Google and Apple announced they would be building a similar feature directly into their mobile operating systems, and are hoping to launch it by mid May. The idea is to use bluetooth transmission between phones, so location data isn't tracked, just proximity to other people's phones. Further privacy protections include using anonymized keys that change every 15 minutes. Still, whether that assuages privacy concerns enough, or whether bluetooth is accurate enough, or if the software even gets done and implemented before we're on the other side of the curve remains to be seen. Until then, places without this tech will have to do it the old fashioned way. Manual contact tracing is not something that can be applied in every stage of this pandemic. It's useful in the early stages to keep a lid on things, but if the number of cases starts to explode, trying to individually reach out quickly becomes a sisyphean task. In the United States there are currently around 2,200 contact tracers employed by government health agencies, but by some estimates we may need as many as 300,000 for contact tracing to be effective. Some places like the San Francisco Bay Area are ramping up their efforts and bringing more on board. However many there are, if they can't keep up with the spread of the virus, or if public testing isn't widespread enough to give an accurate picture of who actually has the virus, then more dramatic measures like physical distancing mandates are necessary. Which is why I'm coming to you pre-recorded “live” from my apartment, where I've been for over a month. But someday public life will resume. I will leave this apartment again. And as we readjust to life on the outside, contact tracers will likely play a key part in making sure the virus doesn't spread out of control again. So, if the day comes that you get a phone call and the voice on the line empathetically wants to discuss your last hair appointment, do everyone a favor and listen to what they have to say, okay? COVID-19 is a huge subject, one that's impacted each and every one of us. Check out this video if you want to know more, and if there's another aspect of coronavirus news you want to see us cover, let us know in the comments below. Make sure to subscribe to Seeker, and I'll see you next time. Thanks for watching and stay safe.