Thread by @Bob_Wachter

The U.S. has clearly turned the page on mask mandates, with many governors – even in blue states – removing mandates in most indoor spaces. apnews.com/article/corona…
Soon, you’ll be allowed to go mask-less indoors. In this 🧵, I’ll address the harder question: should you? (1/25)

During prior lulls (May-June & November, 2021), I resumed indoor dining and was comfortable with unmasked get-togethers with vaccinated friends. But in Dec-Jan, I went back to my Surge Rules: masking indoors (except for with those in my bubble), and avoiding indoor dining. (2/25)

If you’re still following me, I’m guessing you – like me – are struggling with whether it’s time to go back to “normal.” Let’s acknowledge that millions of Americans have already done so. While they’re taking some risk (still a lot of virus around), there’s something… (3/25)

… blissful about “normal”; avoiding all the risk-benefit math & angst.
As case rates & hospitalizations continue to fall, more folks will join them, deciding that risk of getting Covid – & having a bad outcome if they do – have dropped to levels that don’t merit masking. (4/25)

I'm likely to join them in a few weeks. But I wasn’t ready this weekend, when I was went to a college pal’s 65th birthday party in So. Florida. His plan was to serve food/drink inside the house, but the backyard would be the hang-out spot. Good plan, I thought, and then… (5/25)

… it began to rain. 🌧️
So today, I’ll walk thru how I made the choice to go indoors. As with my recent thread on my son’s Covid, I don’t do this because the party was unusual (though it was fun!), but the opposite – because it’s so commonplace. Millions of times a day… (6/25)

… people have to decide whether to don a mask indoors, eat in a restaurant, or mask their kid. I hope my analysis is helpful – whether you decide to remain careful for a few more weeks, or that you're ready to go mask-less. I now consider both to be reasonable decisions. (7/25)

A little context: I’m (still) a fairly healthy 64-y.o. man. I’ve had 3 Pfizers; including boost 4 months ago. Florida’s current case rate is about 100 cases/100K/day, about 1/5th of its Omicron peak but still well above prior lulls. And of course there are many home-test… (8/25)

…positive case that aren’t reported. Hospitalizations have also fallen.
Like most of the U.S., I assume that if I got Covid I’d have a hard time getting the Pfizer oral antiviral Paxlovid, the monoclonal Sotrovimab, or a course of Remdesivir. In other words, despite… (9/25)

…there being 3 therapies that markedly lower the hospitalization and death rates for high-risk outpatients with Covid, none would be available to me if I got infected. (They are being reserved for people at higher risk than me, which is appropriate given their scarcity.) (10/25)

My 3 Pfizer shots have reduced my risk of getting Covid by ~50% – a significant benefit, but breakthroughs are, quite obviously, commonplace. More importantly, the 3 shots have reduced my chances of a severe case and death by about 95% (the booster being key to that). (11/25)

I haven’t gotten Covid yet, and I still consider getting it undesirable & not inevitable.
Why undesirable? 1) Small, but non-zero, risk of a severe infection (though a near-zero risk of death); 2) ~5% risk of Long Covid – & an unknown (probably small but non-zero) risk… (12/25)

… of long-term organ dysfunction; 3) I’m staying with my 86-year-old mom (boosted but at higher risk than me).
So I’m not “over it” – if you are, you’ve probably stopped reading by now. As long as there’s lots of Covid around – & there is – I’m still going to be careful.(13/25)

So that’s the background.
The party: ~40 people, mostly from Northeast, a few from FL, a few from CA. Since outsiders arrived in FL 1-2 days ago, the risk for most is that of their hometown, rather than that of FL. All the states have seen similar drops in case-rates. (14/25)

The host asked everybody to be vaxxed/boosted & to do a rapid test. I'll assume most complied on testing, and that anybody testing positive stayed home. Knowing that most of the group are professionals in their 60s who live in blue states, national demographic data would…(15/25)

predict fairly high vax & “careful” rates as well.
In Palm Beach County, test positivity rate is still ~17%. Based on our experience @UCSF, asymptomatic test positivity rate tends to be ~half the overall test pos. rate (vs. symptomatic rate, which exceeds the average). (16/25)

But I doubt this group's rate would be 8.5%. Given all the factors (demographic predictors of vax & behavior, party’s vax & testing requirement, relatively low case & test pos. rates in guests’ hometowns), I’d guess that 1-3% of asymptomatic people in a group like this… (17/25)

… would test positive for SARS-CoV-2 at this stage of the Omicron surge/de-surge.
Let’s go with 2%, or 1-in-50. That would mean that in a group of 40 people there would be a ~55% chance that at least one person was positive & potentially infectious.(18/25)

Omicron's household attack rate is ~33% – that’s the chances that a family member will become infected by someone w/ Covid living in the same home. In a mask-less group at a 2-3 hour party (vs. a family sharing a home, meals, and bathrooms), it’s got to be far lower… (19/25)

…than that – I'll estimate a 5% chance of getting infected if I come in close contact w/ person with Covid (remember, there's only 55% chance that such a person is there). That chance would drop with good ventilation – which is why we kept two doors open during the party.(20/25)

So that's what I was thinking when the rain began to fall.
On the panel below, I've summarized my estimates & calculations.
(Note that these are my best estimates from the literature, but there's educated guesswork here, since not every situation has been well studied.) (21/25)

As you can see, while getting Covid from the party would be an unusual outcome, it wouldn’t be shocking (~1 in 50 chance).
But getting the kinds of outcomes that would make me regret having gone (hospitalization, death, Long Covid, or infecting mom) would be quite rare. (22/25)

With that, & since the only two alternatives were to leave a party I really wanted to be at, or to eat oysters and drink nice wine in a downpour, I went inside. It was delightful.
3 days later, I feel fine & am confident that I didn't get Covid (will test for symptoms). (23/25)

Having gone through all this (mostly reassuring) math, is the mask gone for good? Not yet – case rates remain high by historical standards, & I don’t need to be mask-less in most indoor spots. I can wait on indoor dining for a few wks, since it’s likely to be much safer…(24/25)

...soon. But in situations where the benefits of going mask-less are high (ie, a party during a rainstorm) or the downsides of masking are higher & risks of infection lower (as with schools), it does seems reasonable to ditch the masks, if not now then pretty darn soon. (25/end)