Comparing Options For Safer Events

post by jefftk (jkaufman) · 2021-11-01T16:30:04.983Z · LW · GW · 19 comments

Yesterday I wrote about how indoor contra dancing, with one set of precautions, seems to be safe enough that I would be ok resuming organizing dances. How safe it is, however, depends a lot on which precautions organizers take. I looked over a range of potential options, many of them suggested in the comments, trying to figure out which ones are worth it. I'm going to try to keep this post general, though the specific scenario I have in mind is a social dance.

Summary: requiring vaccination, requiring (and offering) surgical masks or better, using air purifiers, not serving food, and discouraging cheering are worth it; checking vaccine cards and requiring rapid tests are not.

For each option, let's start by estimating the cost in time and money, and the benefit as a percentage reduction in transmission. For the latter, all numbers are from microcovid unless otherwise specified.

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comment by Tornus · 2021-11-01T17:29:16.594Z · LW(p) · GW(p)

Really solid analysis. Regarding rapid tests:

A pretty important downside in many cases is that they're logistically complicated at a large event. The tests need to lie flat on a table or other surface for 15 minutes. Are you gonna have a giant table covered in tests? Do people come in to test and then go back out? Do they take their test out and perform it in their cars? These are solvable problems, but they can add a lot of complexity and crowding to the checkin area, which is already a problem spot at many events.

With that said, I'm a huge fan of tests for smaller events. Rapid tests let you get four times as much socializing for the same level of risk—depending on your risk budget, your financial situation, and your social ambitions, tests might (or might not) be a game changer for you.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T18:05:05.108Z · LW(p) · GW(p)

They do get you four times as much socializing for the same level of risk, but so do some other options like air purifiers. If you're already doing the others, and you are doing something risky enough or are sufficiently cautious, then rapid tests do make sense.

EDIT: this is also different by country; I'm thinking of the US where rapid tests are somewhat hard to find in stock, and cost ~$12/each

comment by jimrandomh · 2021-11-02T02:51:11.415Z · LW(p) · GW(p)

I'm not sure using the room volume is correct here, since all things being equal I would expect doubling the volume of the room while keeping filtration capacity and occupancy constant to be safer, but this would say it's less safe?

If I imagine a large gymnasium, with a woefully underpowered air filter on one side and a handful of people on the other, then the CFM/person model breaks down. But I don't think the microcovid model is based on consideration of corner cases like this.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-02T10:49:37.223Z · LW(p) · GW(p)

The microcovid model isn't CFM/person, it is CFM/CF. That is, it says you need to have sufficient purification capacity to filter the volume of the room five times per hour. See above for details on the measurements in the study (27x20 room with a 12ft ceiling).

comment by TurnTrout · 2021-11-01T17:52:52.229Z · LW(p) · GW(p)

10min in hassle and testing.

Seems wrong for rapids. I took a rapid with less than 2 minutes of attention this morning. People can socialize while they wait for results. Larger events require more staff time for this, though.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T17:59:09.821Z · LW(p) · GW(p)

Are you counting test acquisition? I don't see anywhere to buy them in bulk as an event organizer, and stopping at a store is easily 10min.

Replies from: TurnTrout
comment by TurnTrout · 2021-11-01T19:25:09.389Z · LW(p) · GW(p)

I’m not. If you’re counting that, perhaps mark that as US-specific, since it’s beyond easy to get tests in eg the UK.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T19:52:49.164Z · LW(p) · GW(p)


comment by LukeOnline · 2021-11-01T19:55:29.753Z · LW(p) · GW(p)

Thanks for the detailed analysis! I massively disagree with your conclusions though. Your claim:

Relative to no vaccination, reduces transmission by 0.5x and reception by 0.17, for a total of 0.08x.

I'm seeing transmission x0.35 ( and x0.11 for reception (, for a total of x0.0385. 

Combined with the protection against serious illness, this pretty much makes COVID a non-issue for vaccinated people, especially the young and healthy. Yes, some risks remain, but car accidents and the consequences of processed food, sugary drinks, a lack of exercise all seem much, much more relevant for a majority of the population. 

You do count the 'costs' of getting a vaccine, but not the costs of getting a mask, because "everybody already has one". The costs of always having a mask with you (and the costs of getting rejected because you forgot your mask), and especially the costs of wearing a mask (for long periods of time, while exercising and socializing), seem much higher than the costs of 'being vaccinated'. 

I live in the Netherlands, and we have an easy, reliable app on our smartphones with a QR code related to our vaccination status. This makes "check vaccine cards" pretty painless. 

"Not allowing food" seems very costly as well. You could skip it for 1 - 1.5 hours of dancing, but if it's a longer event and people are socializing, food seems quite valuable. 

For COVID, I would solely focus on vaccines. Get everybody vaccinated, done, allow normal life to resume. Removing food and wearing facemasks all the time seems way too costly. 

Air purifiers / ventilation / a focus on air quality do seem worth it, but not just for COVID. It helps prevent the spread of other diseases as well, and good air is pleasant and healthy. 

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T20:15:02.128Z · LW(p) · GW(p)

transmission x0.35 ... x0.11 for reception ... total of x0.0385

I'm using's numbers here. If you think they're giving out the wrong numbers you could file an issue at, but they're probably going to want citations in papers and not in news articles.

The costs of always having a mask with you (and the costs of getting rejected because you forgot your mask)

I proposed organizers have surgical masks available, which at $0.08/each is very reasonable. On the other hand you probably already need a mask to get to the event: both public transit and taxis require masks here.

The costs of always having a mask with you and especially the costs of wearing a mask, seem much higher than the costs of 'being vaccinated'.

I agree. The cost of being vaccinated (allocated to a single event) is super low, because it divides across so many activities/events.

"Not allowing food" seems very costly as well.

It depends a lot on the event. Most contradances here already don't offer food; the one I organize is unusual in that it (in normal times) did put out some snacks (usually popsicles) at the midpoint.

comment by EKP · 2021-11-01T18:03:51.980Z · LW(p) · GW(p)

I also think that ignoring the loss of people who can't reasonably dance in masks is a mistake, but that's strictly my opinion rather than a shortcoming of your writeup.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T18:11:51.854Z · LW(p) · GW(p)

At least here maskless dancing wouldn't be an option even if I was in favor of it:

Replies from: EKP
comment by EKP · 2021-11-01T18:14:41.323Z · LW(p) · GW(p)

It isn't now, which means the inclusion of those people isn't counted a loss. When you revisit the analysis in six months or two years, will you remember to put them in then?

comment by EKP · 2021-11-01T17:55:44.619Z · LW(p) · GW(p)

People sweat while dancing. Some people sweat a lot. I have heard that wet, even damp, cloth masks are essentially useless. Does this hold true for surgical type masks as well? If so, many folks will be effectively unmasked for much of the evening, even if they do something reasonable like get a fresh mask every 2-3 dances.

On an entirely separate note, my community has re-started some of its dances with mask and vacc required, no exceptions. This has excluded several families with children who were active participants pre-pandemic. What is your plan regards to families with children? The "I" in BIDA perhaps makes it extra un-pallatable to exclude them.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T19:13:22.560Z · LW(p) · GW(p)

On damp masks, this wasn't something I noticed when we hosted an outdoor contra. People who've held dances like this indoors: is that something you've seen?

With children, Pfizer received the EUA for 5-11 last week, and the CDC will likely sign off this week.

Speaking for myself and not for BIDA, while I think intergenerationality is important, I don't think it is so important that it should preclude having dances before vaccination is available for all, if vaccination is necessary for safety.

Replies from: jimrandomh, EKP
comment by jimrandomh · 2021-11-02T02:23:15.591Z · LW(p) · GW(p)

I think it depends mainly on the ambient humidity. If the temperature and humidity are both on the high side, then ambient humidity plus sweating/exhaling dancers sometimes crosses a threshold that leaves everyone drenched in sweat. It only happens in summer and in spaces without A/C.

comment by EKP · 2021-11-01T20:59:18.627Z · LW(p) · GW(p)

While most dancing children will be covered by the recent EUA, many younger ones (and therefore likely one or both parents) will not. I understand that you yourself have a <1 year old for whom the vaccine availability timeline is unclear. She would not be welcome at the dance events hosted in my area.

Replies from: jkaufman
comment by jefftk (jkaufman) · 2021-11-01T22:21:56.816Z · LW(p) · GW(p)

All the children here who would be capable enough to dance at our regular dances are old enough for the EUA.

In the before times, people would bring infants and wear them in carriers, but I wouldn't bring one currently even if a dance allowed it.

Replies from: EKP
comment by EKP · 2021-11-02T14:57:18.762Z · LW(p) · GW(p)

I'm finding this exchange strangely frustrating. I was trying to ask whether you planned to explicitly exclude children under 2 and/or 5, since my understanding is the local laws would permit an event with them and so your plan in this regard wasn't clear to me from your writeup. I expected there to be either a small additional risk in your analysis from including them or an included cost to not, since then presumably people are paying a sitter (or staying home). I don't have a strong opinion either way on the correct approach. But "I would not personally bring my small child" is not an answer to the question.

I will say that I, personally, have not returned to the dances ~one hour away because they will not permit my <1 year old to enter the building. It's not a principled disagreement, it's just that the cascading impacts mean that it is not worth it to me personally to attend. If my kid were to attend, I wouldn't do a carrier. Various people would trade off sitting out. One venue managed to accommodate this by having a space in a different room (not the one used for dancing) for the kid and the kid-minder, but the main venue that has resumed dancing does not allow entry to the kid under any circumstances. And that's fine! But it means it is not worth it to me to attend. 

I do bring my kid to other indoor places (e.g., shopping, buses) which I understand is not the cultural norm in the Boston area currently.