Thread by @Bob_Wachter

This is one of the most confusing times of the pandemic, w/ a firehose of new Omicron data (lots of fab work on #medtwitter putting it into context). In this (long) 🧵, I'll offer my take on how the new information is changing my thinking & behavior.(1/25)

I'll start with a few general principles & observations (to save space & time I’m largely going to omit primary data – it’s out there; follow @EricTopol to keep up):
1) Things are uber-dynamic. We have far more clarity now than we had 3 wks ago, but many unknowns remain...(2/25)

...More infectious: yes, not sure by how much. Immune evasion: definitely. Severity: conflicting data from UK & So. Africa, even today. Could mean it's same as Delta, could mean it's moderately less. Doubt it's more severe or massively less severe. We'll learn more soon.(3/25)

2) If you’re looking for “this is safe” or “this is unsafe” advice, you won't get it here – the situation is too nuanced for that. There’s safER & LESS safe. And context matters: what might be safe for a healthy 30-year-old could be way too unsafe for a frail octogenarian.(4/25)

3) It’s not about you alone. That healthy 30-year-old can spread Covid unwittingly to someone at high risk, including a loved one. So decisions about risk need to account for risk to others.
4) We’re all exhausted and sick of living this bizarre and diminished life...(5/25)

... Quite naturally, this will influence many people’s decision-making and risk tolerance. But it doesn’t change the risks of those choices one iota. The virus is chipper and ready to go. It continues to deserve our respect, and appropriate caution based on the science. (6/25)

5) Speaking of calibrating behavior, a few mnths ago, I shifted my attitude – Covid will be with us for the long haul, & thus I was personally more comfortable taking calculated risks (ie, visiting family over holidays), in part because “if not now, when?” In other words...(7/25)

...in my risk/benefit calculation, I removed my “Remain Extra Careful; Covid Will Go Away” temporal factor. But now, w/ Omicron cases skyrocketing, I’ve added back that "hunker down" variable – I see the next few months as a time to fortify one's safety behaviors. Why?...(8/25)

1st, Omicron looks to have peaked in So Africa; we'll likely see a familiar surge-then-plunge pattern, just with a much steeper upslope. Second, I’m quite worried about an overwhelmed healthcare system – we’ll rapidly hit capacity limits in meds, beds, ICUs, testing…(9/25)

... and most importantly people (many MDs/RNs out sick too). Trust me, you want to avoid getting sick when the system is stressed. Third, I see the Pfizer oral anti-viral as a very big deal, and it won’t be available for 4-6 weeks (even then it'll be in short supply).(10/25)

6) Hunkering down means trying to limit risky activities. We now appreciate the negative impact of shutting schools. We need to do everything humanly possible (vaxxing, ventilation, testing, incl. test-to-stay) to keep schools open even in the face of a large surge.(11/25)

7) Even if Omicron proves to be less severe, don't get lulled: it's unlikely to be massively less severe. If (let’s say) Omcrn is 30% less severe but cases go up 5-10x (both plausible), that’s still awful, w/ far more hospitalizations & deaths than comparable Delta surge.(12/25)

8) In your own decision making, on top of weighing personal risk (age, comorbidities) & risk of exposure (activities, masking, case rates in your community, incl. fraction of Omicron), we now need to be more nuanced about level of immunity. It’s no longer Immune: Y/N?...(13/25)

Twitter cut me off, grrrrr – will post rest of thread later.

On @donlemon @CNN tonite 7pm Pacific, 10pm Eastern if you want more (completely understand if not!)...

(Resuming prior thread)...Immunity is now (best>worst):
a) 3 mRNAs + infection (super-immune)
b) 3 mRNAs (very immune)
c) 2 mRNAs OR J&J + mRNA (modestly immune)
d) 1 mRNA or J&J alone, or infection alone (minimally immune)
e) No shots AND no infection (totally vulnerable)(14/25)

9) We all should have paid more attention in 4th grade when we were taught to multiple fractions. Why? Because thoughtful decision making now requires you to multiple (brace yourself):
Personal risk (age, comorbidity) x activity (indoor, crowded?) x # of Covid cases.... (15/25)

...in the region (cases/d/100K) x risk-reduction by you & others (masking, ventilation, etc) x fraction of Omicron in region x your level of immunity (zero to super) x how important activity is to you (visiting kids/grandparents vs. seeing a movie.
Exhausting, right? (16/25)

10) While some will say "I'm over this," taking no precautions seems too risky. Yes, most Om cases will be mild, some severe (especially if hi risk), small # fatal, unknown % will get Long Covid. My vote: try to stay safe until threat passes or we're more sure of severity.(17/25)

So what am I doing now? (Context: I'm fairly healthy, mildly overweight 64 yo, 3 Pfizers, no small kids or elders at home, moderately risk-averse. I can work from home most days except when on clinical duty, as I am next week). (18/25)

Would I travel for X-mas? In US, yes. Om still minority of cases in most places, planes safe, no guarantee next X-mas will be safer. Wear N95 for whole flight, minimize eat/drink time. To Europe: no, risk of Om is too high, and bureaucratic nightmare to return if positive.(19/25)

Would I dine indoors? Not anymore, even tho SF has v. low case rate and 80% 2-shot vax rate. But cases will start climbing soon (& fast) & indoor dining not worth risk to me. Outdoor dining: fine for now. Crowded event (sports/concert): not for me at this point.(20/25)

Would I do indoor shopping or work? Yes, but my rule is to wear N95 (or equivalent) in all indoor spaces unless it's a small group that I'm certain is fully (3 shot) vaxxed, & I know all would stay home if feeling sick. Otherwise, mask stays on in indoor spaces.(21/25)

Testing? I test myself & family with any compatible symptom (URI, headache, fever, GI). Note Omicron less likely to cause loss of taste/smell. At $12/rapid test (ouch), tests aren't as accessible as they need to be. Testing before an encounter makes it far safer... (22/25)

...so it's reasonable to test before visiting elderly or other high-risk folks, though I don't test if I'm sure everybody is 3x vaxxed. If I was visiting immunosuppressed or unvaxxed person (incl. a young child), I'd test everybody before gathering.(23/25)

I hope this is helpful. We're all overwhelmed, exhausted and frustrated by yet another Covid Curveball. I hope you stay safe and sane, and let's hope for a quick surge, a milder illness, and that lots of folks choose now to get vaxxed and boosted.(End)