1/ Covid (@UCSF) Chronicles, Day 115
It's been a wild week, with terrible news about new cases, overwhelmed hospitals, and deaths. Plus boatloads of new info on wide-ranging themes. So this’ll be a potpourri thread, covering a few areas that seem most interesting and dynamic.
It's been a wild week, with terrible news about new cases, overwhelmed hospitals, and deaths. Plus boatloads of new info on wide-ranging themes. So this’ll be a potpourri thread, covering a few areas that seem most interesting and dynamic.
2/ Still lots of interest in the end of the “California Miracle.” I wrote this piece in today's @TheAtlantic tinyurl.com/ybaoq9yf on how California went astray. My key point: California let its guard down, in spite of good governance. Complacency may be our biggest threat.
3/ Interesting Bloomberg @business piece on why CA, a blue state, hasn’t been criticized (as red states have) for its surge tinyurl.com/ydcwkzan Reasonable point – one could make similar unfairness claim that TX never got the credit CA got for crushing the curve in March-May.
4/ But article is a bit misleading. It makes California’s surge seem as bad as those in FL-AZ-TX. Yet CA’s per-capita case rate is less than half of that in AZ & FL, & it's 50% lower than TX's (Fig). Good leadership & messaging still matter – CA’s surge is milder because of them. 
5/ Quick look at local data: @UCSFHospitals 21 pts, 11 on vents, ~2.5x times numbers in early June. The datapoint I follow most closely is test positivity in “asymptomatic” patients (mostly hospitalized pts w/ no symptoms of Covid, or patients tested before procedure or surgery).
6/ Not quite a random sample, but fairly close to one – thus offers a decent answer to this question: if I’m in Northern CA, what is chance that a random person – in the store, on the bus, in the elevator – has Covid? Useful, since asymptomatic people are fully capable of spread.
7/ That number @UCSF, which hovered at ~0.3% since we started testing asymptomatic people in March, is now 0.9% (Fig, bottom line). And SF is fairly Covid-cool compared w/ rest of CA, so I’d assume somewhat higher fraction elsewhere in CA, & higher still in more surge-y states.
8/ We also test pts w/ symptoms – this too has bumped, ~3% →7.7% (top line above). So if SF person has fever or cough, they’re still unlikely to have Covid (tho they’re all sure they do). But odds have gone from 1-in-30 to 1-in-14 (& maybe bit higher because of false neg tests)
9/ Bottom line: more virus around in SF, and virus begets more virus, if we give it the chance to spread. That’s why acting safely is more important than ever.
One bright spot: Bay Area cases down a bit, deaths stable (Fig on L) while CA's cases & deaths both rising (Fig R).
One bright spot: Bay Area cases down a bit, deaths stable (Fig on L) while CA's cases & deaths both rising (Fig R).
10/ While we’re better prepared than earlier (my summary, again, below), sadly we’re back to shortages of some key resources, in surging states. In many places, viral tests still scarce, many with turnaround times of 5-7d, rendering the test pretty useless for disease control.
11/ And shortages of PPE & ICU beds are now affecting hard-hit areas like Houston tinyurl.com/yc9f2vxr and Phoenix. Another shocking example of cost of absent federal leadership. Sadly, at this point the Trump administration doesn’t even seem to be trying to fake a strategy.
12/ Turning to other issues – this week @WHO affirmed the reality of aerosolized (vs. droplet) SARS-Co-V-2 transmission tinyurl.com/y97lyh45. While the world of infection transmission experts seems to have divided into camps on this question, it seems more nuanced to me…
13/ ... It seems clear that aerosol transmission can occur – how else to explain cases like China restaurant/AC case tinyurl.com/vp3fraf? But it also can’t be common, or we’d have far more cases than we do. Like most complex questions, the answer is probably in the middle…
14/ It seems sensible that a) infected people (w/ or w/o symptoms) can spread the virus, mostly through droplets (coughing/sneezing) but potentially through a finer mist (aerosol); b) the risk of catching the virus plummets if you keep 6 ft away and if everybody wears masks.
15/ The controversy is partly over whether everybody should wear heavy-duty (N95) masks to block more viral particles (not just droplets). But there are 2 practical problems: 1) there aren't enough N95s for all, & 2) wearing an N95 for hours is really unpleasant – few will do it.
16/ For now, I’m comfortable w/ the assumption that aerosol transmission is rare but does happen, & that distancing and masking (along w/ trying to stay outdoors, ventilation, etc.) is the best we can do if we want to be in contact with other human beings. Seems straightforward.
17/ I heard interesting new theory by ID expert Monica Gandhi @UCSF: wearing masks may not only prevent disease, but – if wearer does get infected – it may be with a lower viral dose and thus cause milder disease. Some support for this from studies in mice & hamsters (below)…
18/ ...along w/ observations from outbreaks on ships – Diamond Princess vs. Argentina ship (Fig on L), and from Czech Republic (Fig R), where mask-wearing is common. If disease is getting less lethal in some places, it may be because mask-wearers are getting lower dose of virus.
19/ If theory is true, may explain why case-fatality rate is much lower in SF (w/ lots of mask-wearing) vs. elsewhere. We've had 3 deaths over last month, despite 1500 new case diagnoses (Fig). That’s not all from healthy living, & no good evidence virus is becoming less lethal.
20/ A few other random topics for your weekend reading:
More info this wk on risk factors. Sadly @nytimes had to sue the federal govt to get data for detailed disparity analysis. It showed that racial disparities in Covid are far worse than we thought tinyurl.com/yd3fqjvl
More info this wk on risk factors. Sadly @nytimes had to sue the federal govt to get data for detailed disparity analysis. It showed that racial disparities in Covid are far worse than we thought tinyurl.com/yd3fqjvl
21/ Fascinating The Daily interview w/ data journalist @gebeloffnyt re: this study & @nytimes overall approach to gathering/analyzing data tinyurl.com/y8kf5qz4 Of all the scientific breakthroughs in this pandemic, data analysis/visualization is among most helpful & impressive.
22/ Another impressive data-based study, of 17M English pts, offered more insights into predictors of bad Covid outcomes tinyurl.com/ycp8eu9u @nature It confirms striking impact of race, gender (M worse than F), & age (pts >age 80 have 20x chance of dying as patients in 50s).
23/ Finally, as predicted, death rates are starting to surge, along w/ cases (notwithstanding SF data). Below: TX, FL, AZ, and CA, & all going up. Yet another reason to be careful – trends blow up the theory that surges are all young people (who won’t die), or it’s all testing.
24/ Speaking of which, in case you’re the one person on the planet who hasn’t seen @sarahcpr do Trump, here’s today’s clip tinyurl.com/yb927mtg Coloring book is perfect. We need a Nobel Prize for comedy.
Back next Thursday for Grand Rounds, and earlier as needed. Stay safe.
Back next Thursday for Grand Rounds, and earlier as needed. Stay safe.
