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1/ I didn’t want to have to write this thread, but we’ve decided to reopen indoor dining in AB despite the better judgement of basically everyone who understands how this virus spreads. So this is my attempt at harm reduction.
2/ The problem with indoor dining during COVID-19 is that two of the major layers against this virus, universal masking and short exposure times, aren’t in place. Wait staff have to interact closely with unmasked patrons for hours, well beyond the (tenuous) 15-minute rule.
3/ We absolutely 100% know that aerosols play a role in the transmission of this virus, and that aerosols can persist in spaces that have sub-optimal ventilation. The issue of suboptimal ventilation has only just started to garner widespread attention in the media
4/ (See the NHL removing glass behind the benches https://globalnews.ca/news/7621637/nhl-covid-protocols-bench-glass-coronavirus/), and public health in Canada spent a long time glossing over the importance of aerosols with this virus.
5/ This means most restaurants probably haven’t looked at ventilation beyond having someone make sure that fans are working. I doubt any have looked at measuring CO2 levels to get even a rough idea of ventilation rates when occupied, nor enlisted HVAC experts
6/ to quantify ventilation more accurately. Note, I’m not blaming owners here, many have done the best they could with the information they were given. But what is a good amount of ventilation?
7/ Experts like @j_g_allen suggest an air exchange rate of 6 as ideal for classrooms ( https://twitter.com/j_g_allen/status/1358022655622938625), where everyone is 2 metres apart and wearing a masks at all times. But in restaurants, people are unmasked while they eat, so we’d want to go higher than 6.
8/ I would be a happy man indeed if restaurants achieved this high of ventilation rates with pre-pandemic infrastructure. I’d bet that most are well below this. Where does that leave us, and what temporary hot-fixes can we do TODAY?
9/ Basically, indoor dining is a bad idea right now. Don’t do it. Do order takeout as often as you like (as indeed I do). IF you operate or work in a restaurant, here are some things to consider:
10/ Keep doors (front and back) and windows open a bit, even when it’s -40 out, because you need to get as much fresh air into that space as possible. Get patrons to wear coats while the eat if they find it too cold. Have patrons wear masks anytime they leave the table.
11/ For staff who interact closely with patrons, use good quality masks that provide more protection from airborne particles than typical cloth masks.
12/ These include ASTM-rated level 2 or 3 surgical masks fitted to the face with a brace (with e.g. https://www.fixthemask.com ) or worn underneath a form-fitting thin cloth mask, KN95s, KF94s, N95s, etc. FIT is very important here; avoid gaps between the mask and face.
13/ Use quality masks for kitchen staff in the back as well. A study out of California (preprint) found that line cooks had the highest risk of dying from COVID-19 of any occupation ( https://www.medrxiv.org/content/10.1101/2021.01.21.21250266v1). We need to provide workers with good quality PPE from airborne hazards.
14/ Run your current HVAC system at the highest rate you can. In the kitchen, run range hoods on the highest setting during operating hours to act as a handy exhaust fan with a high capacity; this should hopefully help draw in more fresh air in from outdoors.
15/ Don’t get me wrong, these are stopgap fixes that act as harm reduction. We shouldn’t be opening indoor dining right now, it’s objectively a bad idea. Don’t use this thread as an excuse to feel safe dining indoors. That isn’t the point of this.
16/ Better solutions take time, funding, and expertise to implement, and realistically will require government support. I strongly suspect the provincial government would be better off in the long run by supporting restaurant owners to keep indoor dining closed right now.
17/ Dealing with another wave of this virus is something we should all do our damn best to avoid. Part of that involves making intelligent policy decisions and respecting this virus (particularly the new variants of concern).
18, end/ Honestly, we are so close to the end of all this, with vaccine production and distribution ramping up. Opening up indoor dining right now is like deciding to drink a gallon of milk on mile 20 of a marathon. It’ll make the last 6 miles very, very awful.
