📊 Time, distance, and masks: a chart
We’ve heard over and over that masks are helpful, but they’re no silver bullet. We’ve had some vague notion that there are situations when they’re just not protective, but little clarity on which those would be.
This chart was published last August as part of a qualitative study, in an attempt to provide some (imperfect, but much needed) guidance to the general public as to how long to stay somewhere and how far apart to stand from others based on the size of the crowd and on whether they are masking up. The authors, a team of clinical researchers, physicians, and fluid dynamic experts from Oxford University and MIT, are quick to point out that there is plenty of investigating left to do, but this is a good start:
In all red situations, you’re looking to stand at least 2 metres (6 feet and 7 inches, so round up to at least 7 feet) away from other people. Always adapt to circumstances, too:
“Coughing or sneezing, even if these are due to irritation or allergies while asymptomatic, would exacerbate risk of exposure across an indoor space, regardless of ventilation.”
… and regardless of mask status because as we know, forceful breathing reduces the effectiveness of masks.
It’s widely understood that duration is a factor, but the cut-off of short to prolonged time is unclear. They explain countries have established thresholds to exposure at anything from 5 to 15 minutes (adding that they’ve seen no research to back this up), and they use one example of a restaurant where 10 people sitting at three different tables were infected within an hour.
How to use this: Mask or no mask, don’t spend time with other people in poorly ventilated places, even if they’re not crowded. Mask or no mask, avoid crowds, indoors and outdoors. For the love of everything that is holy: don’t go to the theatre, don’t go to church, temple, mosque, don’t eat indoors at restaurants, don’t go to bars. If you do not have a choice, a two-metre distance is an absolute minimum. As for duration, use your best judgement. I'll be working on the assumption that the cut-off from short to prolonged time is between 15 and 30 minutes.
Also, share the chart! They’ve had it translated into 28 languages. Co-author Trisha Greenhalgh posted them all in this thread (Amharic is so pretty):
👩🔬 A sane declaration
In response to the recklessness of the Great Barrington Declaration* (I am not linking to it, feel free to search it, but please don’t spread it), a growing group of (actual) experts wrote up the John Snow Memo. No, not that know-nothing Jon Snow (though that would’ve been some mad shade, there for which I would’ve so been). John Snow who founded modern epidemiology, of “dirty water’s gonna give you cholera” fame:
[The herd immunity approach to dealing with the pandemic] is a dangerous fallacy unsupported by scientific evidence.
How to use this: share it far and wide. If you happen to know someone who is a “scientist, medic, researcher, modeller, healthcare or public health professional,” encourage them to sign it. The more, the merrier, it’s how we fight disinformation.
*A pile of drivel capitalising on Covid fatigue and sponsored by libertarian group AIER that calls for everyone to just go ahead and get sick — with a side of “eh, sure, protect the olds if you can bother” — so we can get over this at once, hahahaha *sob*
🥖 Sourdough panel!
It’s done. It was fun and interesting and if you’d like to meet a starter named Bavid Doughie, please watch it here:
How to use this: improve your loaves with SCIENCE!