Today's update on SF/@UCSF numbers. Bottom line –huge increase in cases & test positivity. Hospitalizations still pretty benign (though early signs of an uptick). Most remarkable stat is our asymptomatic test positivity rate (ATPR) @UCSFHospitals – now ~7%, or ~1-in-14.(1/16) 
You'll recall that ATPR is fraction of pts getting care (hospitalization, procedure) @UCSFHospitals who we test for Covid routinely, even tho they have no symptoms. I use this as a rough approximation of the prevalence of Covid in Bay Area people who have no Covid symptoms.(2/16)
The ATPR was as low as 1/500 (0.2%) a few mths ago. Today, our 7d ATPR is 6.9%, and last 3 days it's ~8% (going up fast).
If its 8%, it means 1-in-12 people in SF who feel fine would test positive for Covid.(Not all would be in their infectious period, but most would be.)(3/16)
If its 8%, it means 1-in-12 people in SF who feel fine would test positive for Covid.(Not all would be in their infectious period, but most would be.)(3/16)
Does that mean that we should treat everyone – even fully vaxxed – as if they might have Covid? With those odds, that wouldn't be wrong. Does it mean I'm going to wear a mask in my home w/ family? No – I know they're all vaccinated x 3 shots & being careful. But still...(4/16)
...the (scary) math is what it is, & Omicron's breathtaking infectivity is changing the odds in ways that are hard to grok.
You might be wondering whether all these asymptomatic people testing positive are unvaxxed. Here in SF, we don't see many unvaxxed people, and...(5/16)
You might be wondering whether all these asymptomatic people testing positive are unvaxxed. Here in SF, we don't see many unvaxxed people, and...(5/16)
...in any case, our data gurus have done breakdown (Fig). Shows that ATPR is in fact higher in people where we can't confirm vax status (presumed unvaxxed), but not THAT much higher: 6.3% vaxxed (booster status unknown), vs. 8% unvaxxed. So vax offers only mild reassurance.(6/16)
Let's turn to SF case & test + rates – the theme is the same. (We don't get to the good news until we look at hospitalizations, but even there we now see a few dark-ish clouds.)
In SF, the 7d avg=305 cases/d but last few days were in ~800-900/day, up from ~50/d last month.(7/16)
In SF, the 7d avg=305 cases/d but last few days were in ~800-900/day, up from ~50/d last month.(7/16)
So even in highly vaxxed, still mask-y SF, we're beginning to see a tsunami of cases, mostly breakthroughs (expected, since >80% of people vaxxed). And SF's test positivity curve has a similar vertical shape (Fig), with a 7d avg of 5.2% but more like 10% for last few days.(8/16)
Today, a reporter asked what ATPR is in other cities. Answer: I don't know; I've not seen anyone else report it. But if @UCSF is ~8% in Covid-light, vax-heavy SF (w/ a ~10% overall test + rate), one can only imagine what it is in NYC, where the city's test + rate is ~20%.(9/16)
Bummed? Me too.
So let's turn to the still-good-ish news re: hospitalizations. SF still sees no uptick in hospitalizations (Fig) – just 34 in entire city (a lag; data as of 12/24). Further evidence that the average Omicron case is far milder than Delta. Thank goodness! (10/16)
So let's turn to the still-good-ish news re: hospitalizations. SF still sees no uptick in hospitalizations (Fig) – just 34 in entire city (a lag; data as of 12/24). Further evidence that the average Omicron case is far milder than Delta. Thank goodness! (10/16)
As I said last wk, this can't possibly hold: with this massive a surge in cases, some bump in hospitalizations has to follow (even if Omicron is substantially milder in a highly vaxxed city). We're seeing earliest signs of it @UCSFHospitals – the first hints will be...(11/16)
... in non-ICU hospitalizations, since ICU stays typically come later. And in fact we do see a new signal: our non-ICU ("floor") admits have risen from 10-12 last week to 18 today, a subtle but I think meaningful rise.(12/16)
Breaking this down by vax status (Fig) shows hospital cases in "fully" (2 or 3 shots) vaxxed are up only a little stable; biggest uptick is in unvaxxed. Note also that virtually all the pts on ventilators for last few mths have been unvaxxed, a pattern I expect to persist.(13/16)
How to process all of this? Omicron continues to be astoundingly infectious. We now need to assume that nearly everyone might be infected... and infectious. But the evidence grows that Omi is a milder illness in most people, particularly the vaccinated. Personally, I'm...(14/16)
...reacting by being more cautious – it feels like the right thing to do, for me and my contacts. So no indoor dining, N95s when indoors except small 3x vaxxed groups. Even this: given data on infections via lingering aerosols, I now keep mask on entering empty elevators.(15/16)
But these data will also, understandably, cause a shift in thinking, since consequences of Covid are now less dire (particularly if vaxxed!) & the behaviors needed to avoid infection are growing more challenging and – as we're all seeing in friends/family – less reliable.(16/end)
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