Post Vax Best Practices
May 23, 2021 3:48 PM   Subscribe

  • All 65+
  • 4 fully vaccinated
  • 1 unvaxxed, often among unknown vax status, often masked
  • All in a sports van together for 2-3 hours
All masked all the time? If not, who and when? Advice appreciated.
posted by maggieb to Health & Fitness (14 answers total) 1 user marked this as a favorite
What's the worst that can happen? Someone has COVID and gives it to someone else and that person dies. If you were asking whether a group with all at least partially vaccinated, that would be a closer call. If you must do this, then masked all the time and maximum ventilation (windows open) and maybe a temperature check would all be a good start.
posted by pipeski at 3:56 PM on May 23

The most recent CDC guidelines say that for a "small, indoor gathering of fully vaccinated and unvaccinated people from multiple households" (the closest thing that matches the scenario you describe), unvaccinated folks should wear a mask and fully-vaccinated folks can go without.

In a similar situation, I know many of my fully-vaccinated friends would choose to wear a mask anyway, as well as keep the windows open as much as possible, because they are high-risk and unsure whether catching COVID would be as mild for them as it would be for other fully-vaccinated folks. Also because in general we're all adjusting to this new world with an overabundance of caution.
posted by rhiannonstone at 4:19 PM on May 23 [9 favorites]

You may also consider grabbing one of those new 15-min at-home tests you can get in any drugstore.
posted by thejoshu at 4:37 PM on May 23

When we think about the effectiveness of masks, we have to think in context of an aerosolized virus. Masks stop the distance aerosols spreads, and keeps it close to the person, or directs the aerosols upwards or downwards.

In an enclosed space for several hours, the aerosols have a much greater chance of bypassing the masks anyway.

The number of things that would need to go wrong just enough for masks to be the deciding factor here is breathtaking.

First, one of the vaccined people would have to be a breakthrough case.
Second, that breakthrough case would have to be in the pre-symptomatic stage.
Third, that breakthrough case would have to be transmitted (which we know is less likely with breakthrough cases, and is already only a 50/50 chance even with your spouse).
Fourth, the breakthrough case host would need to give enough aerosols to transmit the virus without a mask on, but not enough with a mask on.
Fifth, the start/end to the destination would need to not have a similar effect.

Since clean, fresh air is a great way to prevent aerosols buildup, my recommendation is to run the HVAC in the car, or crack some windows, if concerned, before wearing a mask as the primary step to reduce transmission.
posted by bbqturtle at 4:47 PM on May 23 [6 favorites]

I would go on the trip, and would have everyone wear a mask to be on the safe side. I mean, how hard is it to do that?
And crack the windows.
posted by SageTrail at 5:02 PM on May 23 [2 favorites]

I'm unclear what you mean by "1 unvaxxed . . . often masked." They are either being diligent or not is how I'd think about it. If they are unvaxxed and hang around other unvaxxed people and aren't always distancing & masking, they are obviously not following good behaviors. If you just mean they don't wear a mask when walking alone outdoors, they count as good. The current rate in your area is another factor.

If you can test the one unvaxxed person that would cut you down to zero. Absent more info I'd go with the CDC guidelines I guess. If you can keep the windows open, great. That's probably the one thing that further reduces the negligible risk in a meaningful way.
posted by mark k at 5:12 PM on May 23 [1 favorite]

Best practice per CDC in this situation is for only the unvaccinated to wear a mask, which it sounds like that person was going to do anyway. The trip sounds short enough for everyone to reasonably agree to wear masks if anyone in the group distrusts the vaccine and requests that.
posted by michaelh at 6:19 PM on May 23 [1 favorite]

One thing that I have found helpful is to do a very, very rough calculation of the probability that the one unvaccinated person has an active case of COVID.

For my hometown, the New York Times COVID report says there are currently 2 cases per 100,000 people. Multiply by 14 (waiting period for new cases to become symptomatic or get over it) then multiply by 4 (assume 3x as many positive cases as reported) and divide by 100,000 to get the percentage.

Doing the math, I get .00112 or 1/10th of percent of the population will actually be carrying around a possibly infectious case of COVID. Round up for risky behavior, round down for vaccination. If we factor in the risk of the other passengers, 99.888% chance one person doesn't have it, raise to the power of four, the chances that no one in car has COVID is .9955 - still well under 1 in a 100 if you are all from San Jose.

For Lewiston-Auburn Maine (highest rate in US) the chances the one person has it is .0180 or almost 2 in a 100. Multiply .982 by the four people in the car, and the chance that no one has it goes to .9299 or about a 7% chance that someone in the car has COVID.

These numbers are extremely rough estimates and how you feel about those risks will vary widely from person to person. In any case, you can make things safer is someone does have COVID by (#1) add lots of freely circulating fresh air (easy fix in a car, helps tremendously)
and (2) wearing masks.

By the way, using the same math, the chances of a random stranger in San Jose carrying COVID back in January was about 4%, that chances that a group of four random people were all covid free was only 85% or about a 1 in 7 chances that someone was infectious, even in that small group of just four.

I know my mind is having trouble adjusting from living in world where four people meeting in San Jose have a 15% risk of Covid vs same four people have <0.5% risk.
posted by metahawk at 6:38 PM on May 23 [10 favorites]

oops. Did my math on a total of four people in the care. Probabilities get worse with five but by how much really, really depends on the community rate that you start with. And of course, the biggest thing influencing the community rate is the rate of vaccination. Math says getting vaccinated helps everyone get back to normal faster.
posted by metahawk at 6:43 PM on May 23

I read somewhere (no idea where, since feverish googling has been my m.o. for fourteen months) that you create a barrier of wind, and isolate the unvax'd beyond it, e.g.:

A) Unvax'd in shotgun, with the driver's window and middle passenger window open.
B) Unvax'd in the back row passenger seat, with the middle passenger window and the back driver's-side window open.

In any case, all the vax'd people I know would wear their masks (for various reasons). Good luck.
posted by mahorn at 7:07 PM on May 23

The problem with doing the math based on averages for the whole population is that the unvaccinated person isn't an average person. The fact that they're unvaccinated at a time when the pandemic is still ongoing and vaccines are readily available makes them on average much more prone to risky behavior. (Since we have no data on why they're unvaccinated, statistically they're far more likely to be "vaccine-hesitant" or an anti-vaxxer rather than medically ineligible.) And as was pointed out above, there are really only two categories of masking - either all the time or not all the time - and they've chosen the latter, also indicating that they're more likely to engage in risky behavior. Personally I wouldn't ride in a car with them for 2-3 hours each way - I'm not sure that I'd even trust them to keep their mask on for the duration of the trip.
posted by Umami Dearest at 9:10 PM on May 23 [13 favorites]

The most recent CDC guidelines say that for a "small, indoor gathering of fully vaccinated and unvaccinated people from multiple households" (the closest thing that matches the scenario you describe), unvaccinated folks should wear a mask and fully-vaccinated folks can go without.

Arguably, the relevant CDC guideline would be the one for public transportation (ie, multiple people of varied vaccine status crammed into a vehicle for hours), which would mean that everyone should be masked.

Also, it sounds like the people involved have decided they are doing this and the only question is about protocols, but it's worth remembering that one option would be to say "nope, I'm not completely comfortable with this" and drive separately.

And as was pointed out above, there are really only two categories of masking - either all the time or not all the time

Masking is like any other kind of harm reduction -- there is still value in doing it even if you aren't perfect about compliance (like ideally someone should wear a condom with all their hookups, but there is still risk reduction in protection that is used only sometimes). That said, I agree with the comments that someone who is not vaccinated, doesn't mask consistently, and doesn't follow social distancing guidelines is making a set of choices that put them at higher risk and make it a different judgment call to be sharing air with them in an enclosed space.
posted by Dip Flash at 6:33 AM on May 24 [2 favorites]

Given that masks aren't meant to protect you from 2+ hours of exposure at close distance, the question is more "do I feel safe making this trip at all?" rather than "which of us need to wear masks?"

Personally, this is a risk I would take. I wouldn't bother with masks in the car unless others in the group preferred me to wear one (and in that case, I'd be doing it for manners reasons rather than out of any expectation that it protects us). If we're interacting with other people outside the van (stopping for food, etc.), I'd probably mask up for that.

(I would, however, absolutely use someone's unvaxxed status as an excuse if I didn't want to hang out with them.)

For vaccinated people, certainly risk still exists (a friend's vaccinated mom just caught COVID but was asymptomatic), but I think a lot of mask wearing -- certainly in cases like yours where the exposure is more than a few minutes -- is a matter of etiquette rather than of medical risk management. I expect "would you prefer that I wear a mask here?" is a question we'll be asking each other for the foreseeable future, and I think we ought to be gracious with anyone who prefers to continue masking.

Going unmasked is a bit like smoking around other people: It's rude to light a cigarette in a room full of people -- it's likely someone there will not be comfortable with this -- and even if you're just with a couple friends, you shouldn't do it without their permission. Some people still won't want to be around someone who was smoking earlier. And while a single cigarette won't kill you, but everyone smoking all the time creates significant public health issues. (It sure would be nice if you could sniff someone and immediately tell whether they've been practicing good mask hygiene.)

But the short answer: Anyone who's not feeling healthy that day should stay home. If anyone wants everyone to wear masks, you should all wear masks. If you all agree to skip the masks, you're jointly taking a pretty tolerable risk.
posted by katieinshoes at 10:27 AM on May 24

This is a bit of a smart-assed answer, I suppose, and perhaps not realistic, but I'd say the non-vaxxed person can either get their own ride or just not come.
posted by papercake at 12:00 PM on May 25 [1 favorite]

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