Source: Wikipedia
Yesterday, my wife and I got onto a bus packed with un-masked strangers. When we got to where we were going, we spent some time in indoor spaces packed with loud crowds of eating, drinking, non-masked-wearing strangers. Then we got back on that bus and went home.
In hindsight, this may not have been the smartest thing we ever did. It takes just a little math to realize it’s a pretty good bet that some COVID was spread at the event we attended.
It wasn’t our intention to do that. It never is, I guess. All I really wanted was a nice plate of pirohi. What I got was a lesson in why we’re still in a pandemic. Or, at least, in how thoughtless the average American is.
Our experience and our mistake.
My wife and I went to an outdoor ethnic festival yesterday, at a church here in Northern Virginia. We’d gone to it a few times in the past. My older brother used to take my mother there every year.
My thinking was, hey, it’s mostly an outdoor festival, how risky could that be? On top of that, the organizers said, in plain English, that masks were required in all indoor spaces.
Our first mistake was the shuttle bus. This fair is held half a mile from the shuttle bus parking. We figured we’d park and walk. But when we got there, we saw that walking was not an option. There was no place to walk — no sidewalk, no shoulder. We had to take the bus to get there.
OK, fair enough. A bus is an indoor space. Presumably, everybody will have to wear a mask in that indoor space. Says so right on the advertisement for the fair. Heck, there’s still a Federal mask mandate on public transit, because that’s a great place to catch a case of COVID.
And besides, this fair attracts an older crowd, and everyone who has ever attended it knows that. Gray hair, canes, and walkers were in abundance. Even absent the fair rules regarding mask use in indoor spaces, common sense and common courtesy would indicated that everybody would mask up. If not for themselves, then in deference to the health of the middle-aged and older persons present. Who wouldn’t be willing to wear a mask for the ten minutes it takes to get from Point A to Point B. In a crowded bus full of older people.
I would guess that 60% of the people on the bus were not wearing masks, including the bus driver. Who was, however, willing to hand you a free mask if you wanted one. Just not to wear one. I saw no takers for the free masks.
The icing on the cake was the unmasked woman behind us who loudly proclaimed that she was done with masks. Unprompted. Just to let us all know. So this wasn’t just a non-mask-wearing crowd, it was a proudly non-mask-wearing crowd. And making sure those sissy mask-wearers knew it.
What should have tipped me off was the preponderance of Trump bumper stickers on the cars in the parking lot. But that didn’t set off a warning flag in time. It’s tough to turn on a dime when you hit the unexpected. We’d driven all the way there, and so on. It would seem foolish to turn around just because we’d have to share a bus ride with a bunch of Trump supporters.
That statement isn’t about politics per se. It’s about the Republican party being the anti-mask, anti-vaccine party. That has been repeatedly demonstrated, objectively and empirically, with survey data. And you can’t weasel out of that conclusion by focusing on “mandates”. We know they’re against mandates. It’s that Republicans themselves, as individuals, are far less likely to be vaccinated, or to wear a mask.
Anti-mask attitude and anti-vaccination attitude go hand in hand. It’s really not smart to hang out with a crowd that’s likely to have a low vaccination rate. (See the Virginia data below — COVID-19 is circulating among unvaccinated Virginians at a rate that is higher than all but six U.S. states.) In hindsight, I have to wonder what the vaccination rate was for that crowd.
We didn’t turn around when we saw the line for the bus. But we should have. I mean, it’s not as if you had to show your vaccination card to get into the fair. We knew that. But we should have figured out the actual situation based on the lineup for the bus.
And we should have reasoned out what the situation in the indoor sections of the fair would actually be, despite what the organizers said. Because, while mask use was required for the parts of the festival held indoors, nobody was enforcing that, either. With exactly the consequences you would expect.
I finally woke up when we went to buy some baked goods. I looked around the crowded room, looked at all jolly loud unmasked people and I finally said, “this is not for me”. A poppy seed roll was not worth the risk. We left.
So we went, I had my pirohi (seated outside), we hung around a bit, and we returned. Truly amazed by the cavalier attitude of my fellow citizens, and of the church that organized the festival. This was a crowd heavily weighted toward older people. But as far as most people were concerned, there was no need to take any precaution.
We’re a little wiser. Hopefully uninfected. And a lot more determined to check out the circumstances before going to another outdoor festival.
You can’t spend your life cooped up in your house. But I’m sure not going to spend it in the company of people who can’t take simple precautions, in a high-risk situation, in the presence of a vulnerable population.
It’s not just that I don’t want to hang out with stupid people. It’s also that I don’t want to end up sharing in their stupidity.
Because, at the end of the day, who was stupider? Was it the woman behind me who proudly won’t wear a mask? Who probably isn’t capable of understanding what the odds are? Or was I stupider, because I understood the risks but went ahead anyway?
A little math on why this was a bad idea.
In a nutshell, the odds that COVID-19 was spread at this event are pretty good. And even a little spread, in a mostly elderly crowd, is pretty bad. I’ll walk through that one point at a time.
Background 1: This is still a dangerous disease
Source: CDC COVID-19 data tracker.
Based on the most recent figures from CDC, over 8% of all persons diagnosed with COVID-19 end up hospitalized. Putting that another way, one person in twelve who is diagnosed with COVID-19 ends up in the hospital.
Vaccination reduces your risk of hospitalization, but as far as I can tell from Virginia data, that’s almost entirely by reducing your risk of infection in the first place. If you get infected, your risk of hospitalization as a vaccinated individual does not seem to be vastly different from the un-vaccinated. At least, not recently, in Virginia. Below, in the most recent week of data, in Virginia, the un-vaccinated had 15.3 times the rate of infection, and 16.2 times the rate of hospitalization. Not much of a difference. So that means most of the reduction in hospitalization risk is due to not getting infected in the first place.
Source: Virginia Department of Health COVID-19 dashboard.
Background 2: This disease is particularly dangerous for older people.
Older people remain at much higher risk for adverse outcomes from COVID-19. Hospitalizations, in particular, are concentrated among the middle-aged and elderly. So that 8% of diagnosed cases, on average, grossly understates odds of hospitalization for older persons, if infected.
See the peak of the hospitalizations graph below? That’s the age group my wife and I are in.
Background 3: This disease is widely circulating in the population of Virginia.
In Virginia, we’re at about 40 new cases per 100,000 per day. I won’t bore you with the math, but my best guess is that on any given day, the stock of actively infectious individuals circulating in the community is about 12 times that. Or, about a half-percent of the population.
That may not sound like much, but if you’re in any sort of enclosure with a lot of people, a bit of arithmetic shows you that you’ve got a non-negligible chance of coming across somebody who is infected.
Background 4: The odds on the bus go round and round.
Let’s say you need to take a 40-person shuttle bus to and from the event. There’s about a one-in-three chance that you rode that bus with somebody who was infectious with COVID-19. (Calculated as 1 – (0.995^80) = 0.33).
But your actual risk of infection isn’t quite that large. For one thing, the ride is short. And for another, disease transmission typically occurs only when you’re in the seat adjacent to the infected individual. Call that five possible seats, on each of two bus ride. Your odds of sitting next to an infected person are more like (1 – (0.995^10) =) 5 percent. Couple that with a short ride, and a high-filtration mask, and the odds of getting a infectious dose seem reasonably small.
The upshot is that the risk of spreading infection on that bus-full of masked passengers isn’t trivial. But it’s not huge either.
Background 5: Now re-think that from the perspective of the crowd.
The calculation above is the perspective of one individual. Each individual has about a 5 percent chance of getting a nice, solid exposure to COVID-19.
Now rethink that whole calculation from the perspective of all of the individuals involved. Assuming I have the basic numbers right — 40 cases / 100K / day means that about 0.5 percent of the population is infectious with COVID-19 — then of the population using shuttle parking, five percent got a 10-minute exposure to someone with active COVID-19.
Nothing up my sleeve. Just math and a few assumptions about the ratio of undiagnosed to diagnosed infections, and average length of infectious period. (Assumed 2 to 1, and 4 days, respectively — that’s where the factor of 12 comes from.)
My wife and I were, of course, wearing N95 masks, when we weren’t outside, eating. We own them, it takes all of ten seconds to put one on, and we’d have been stupid not to wear them. That should shift our odds of infection considerably. But nothing is foolproof.
There were a whole lot of people — including a whole lot of older people — who took a significant risk of COVID-19 exposure and almost certainly had no clue they were doing that. Without bothering to wear a mask. Just in getting to and from the fair. Not even considering the crowded, non-masked indoor spaces at the fair.
And so, in the end, I’d be willing to bet a large sum of money that some brand-new cases of COVID-19 were generated at that ethnic festival. Given the hundreds and hundreds of people, and just a bit of calculation regarding the bus ride, it’s practically impossible for that not to have happened.
I’d guess those buses were moving 250 people an hour, for five hours. With a five percent exposure rate for the population moving them. So maybe 60 people got a good solid exposure. With that many people, and most people taking no precautions, I’m guessing the odds are pretty good that some individuals picked up a COVID-19 infection just getting to and from the fair.
I don’t think this was any sort of super-spreader event. Too much of it took place outdoors for that. But the odds are that there was some spread of COVID-19 there. And that’s the essence of how a pandemic proceeds.
