字幕列表 影片播放 列印英文字幕 Hey everyone, welcome back to Seeker. You may have noticed that I am not in front of my usual rainbow-tastic backdrop because, as I’m sure you’re aware, we are trying to limit the spread of the novel Coronavirus by staying in and social distancing. So welcome, everyone, to my apartment! If you’re trapped at home like me, washing your hands for 20 seconds several times a day, and only occasionally going out to grab essential supplies in non-panic levels, you’re doing your part to slow the virus’s spread, and your actions will save lives. You’re also probably like me and looking at all the doorknobs in your house like they’re out to get you. So let’s address how long the virus can linger on surfaces, and what you should be wiping down to keep yourself and others as safe as possible. First off, let’s just say that the scientific literature on the subject is pretty limited. The novel coronavirus is just that: novel, new. Its full name is SARS-CoV-2, and like all sequels, it's worse than the original. It’s taken the world by storm, and even though it is a very pressing threat, scientific research moves at a much slower pace. It takes time to study it, have the results peer reviewed and confirmed, and then published. So some of this information is still in the pre-print phase, and may be changed or tweaked, but I promise you it is much more rigorously tested than a lot of the information that’s flying around on Facebook or Twitter. One study from the National Institutes of Health that at the time we wrote this was available in pre-print, examined how long the virus can remain viable on a few common “fomites,” or materials which can transmit the infection. The fomites that were tested were copper, stainless steel, cardboard, and one of the most common plastics called polypropylene, which is used to package food, for tote bags, and in many kitchen items. The researchers found copper was the toughest for the virus to survive on; four hours after exposure they couldn’t find any that were viable, or capable of infecting a person. Cardboard was the next toughest for the virus, with none found viable after 24 hours. Stainless steel and plastic were much more accommodating, with viable examples detected even 72 hours after exposure. But let’s mix in a little good news with the bad. Just because there were viable viruses doesn’t mean their concentration wasn’t dropping. In fact the concentration dropped quite a bit, and it did so faster on the steel than on the plastic. That’s because most viruses degrade outside a living host, so while you can still get infected by contacting a contaminated surface days after the virus was deposited there, it’s not as risky as within the first few hours of contamination. The study also examined how long the virus can remain viable when suspended in aerosols. The experiment lasted three hours, and the virus remained viable the entire time, with not much of a drop in concentration. However, and I cannot stress this enough: that does not mean the virus is “airborne,” like the virus that causes measles. The researchers aerosolized this virus artificially by spraying it into a mist and keeping it aloft inside a special rotating drum. In contrast, when an infected person exhales or coughs, the virus is typically carried in larger droplets, which do not stay suspended in the air as long. If droplets land on a person or a fomite, then yes... that’s a problem. But from what we know, the virus doesn’t transmit like measles, which can stay infectious in the air for half an hour or more. Now, these are all results from tightly-controlled laboratory settings. In the real world, it’s possible the UV light from sunshine disinfects surfaces faster. It’s also possible that even though your package was in transit for over 24 hours, it was just sneezed on before it was left at your door. So don’t take these as hard and fast rules, but more guidelines. Hopefully what this information really does is help make clear why you’ve been asked to wash your hands frequently and avoid touching your face and going out. SARS-CoV-2 spreads most effectively from person to person. If you touch surfaces you fear can be contaminated, avoid touching your face because you can infect yourself through your mouth, nose, and eyes. Washing your hands thoroughly with soap destroys the virus. As a bonus, soap micelles also envelope the fragments of viruses and carry them away, which is what makes soap more effective than hand sanitizer. Hand sanitizer and alcohol wipes are still effective if they’re over 60% alcohol, so go ahead and wipe down frequently touched surfaces like door knobs, remotes, and light switches daily. And don't forget your phone, which touches your hands and face a lot, so that should be wiped down often. And most importantly: do not panic. At a time like this, good information saves lives. Stay safe, stay smart, and do your part. We want to help get you through this world-changing event, so if there’s something else about SARS-CoV-2 you would like to know, tell us in the comments and we’ll do our best to answer your questions thoughtfully and accurately. Check out this explainer video we made about the virus and, to keep up to date with our Coronavirus coverage, make sure to subscribe. Thanks for watching, and I’ll see you next time on Seeker. Social distancing party at my place! Nobody's invited.