Bob Wachter Profile picture
Chair, UCSF Dept of Medicine. Career: What happens when a poli sci major becomes an academic physician. Author: "The Digital Doctor". Hubby/Dad/Golfer.
Antone Johnson Profile picture eDo Profile picture Ross Grayson, MPH, CIH Profile picture Just Add Zombies Profile picture Norris Battin Profile picture 114 added to My Authors
12 Oct
Latest twist in "aspirin for primary prevention" story (rec: don't do it) hits home.… When I was in med school, I told my dad (age 52) to take an ASA daily. He was a stressed-out guy, heart attacks were common, & early evidence on ASA was supportive.(1/8)🧵
A few months later, I got a call that he had passed out on the train. The cause: a huge upper GI bleed. I felt terrible – I was pretty sure that my aspirin had caused his bleed. This was, in essence, my first prescription, and I'd nearly killed my father. I rushed home. (2/8)
The GI doc let me watch as he performed dad's endoscopy, expecting to find stomach inflammation or an ulcer. I heard the doc gasp when he found a large polyp at the stomach-esophagus junction – it was clearly not what he expected to see. Turns out it was a stomach cancer. (3/8)
Read 8 tweets
20 Aug
Covid (@UCSF) Chronicles,Day 521
I can't resist one more thread on boosters. I see lots of debate on data: about antibody levels, infections vs severe infctns, etc. I don't see much about the big issue: the tension between 2 perspectives – that of individuals vs. society.(1/25🧵)
It's particularly tricky when talking about a global pandemic since (as we've learned, painfully) no person is an island: individual behavior impacts the collective & vice versa. In pandemics, there's also the matter of who comprises the collective: just domestic or global?(2/25)
For those who don't follow healthcare closely, you've stumbled into a longstanding tension in health policy, one that maps pretty well to two different and (mostly) fraternal fields: clinical medicine and public health.

As a physician (though one with public health... (3/25)
Read 25 tweets
19 Aug
Lots of criticism of new booster plans, much of it re: how much of ⬇efficacy # s are due to confounding vs truly ⬇effectiveness. To me, it seems incontrovertible that vax effectiveness is ⬇significantly, though amount of drop – particularly vs severe cases – is unclear.(1/7🧵)
I'm in support of the new booster plans. This is anecdotal, but in past week I've heard of 2 fully vaxxed people in 70s who died of Covid. With Delta & waning vax effectiveness, this will happen. Even if failure to wear masks contributed to the cases, that'll happen too. (2/7)
We can make two types of errors here: acting too early and acting too late. Given that it'll take 4-6 months to roll out boosters to 200M people, I think we need to skate to where the puck is going. To my reading, the evidence we have regarding waning vax effectiveness... (3/7)
Read 7 tweets
4 Aug
Covid (@UCSF) Chronicles, Day 504

To me, the most confusing time in the pandemic was May 2020, as we exited lockdown and nobody quite knew what they should & shouldn’t do (clean the mail? touch the dog?).

But now is giving May 2020 a run for its money. (🧵1/25)
Today, a smorgasbord of some of the most confusing issues: Delta, masking, vaccine efficacy, vax mandates, boosters.

Bottom line is that my thinking has changed. Six months ago, I felt like I understood all of the key variables when it came to the virus & vaccines. And… (2/25)
…when I learned that a variable had changed w/ Delta, I assumed nothing else had.

But now I see that it’s best to assume that nearly every parameter is different – usually for the worse. That creates cognitive vertigo, but it matches the facts on the ground. (see below.)(3/25)
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30 Jul
The CDC document that was discussed in @washingtonpost today… is now on line:…
The WashPo shared it with me before publication for reactions, and I'm quoted. Some thoughts follow. (1/13)
My overall view: we knew much of what's in here, but there's some new information & analysis. In some cases it's brand new, in others it clarified something we knew before. In virtually all cases, the new stuff's a bit worse than I expected. Here are the key findings: (2/13)
1) Delta is much more infectious than the original: they estimate an Ro of 5-9, vs. the 2-3 for the original, which makes Delta "as transmissible as chicken pox." We've been estimating Ro of ~6 for Delta, or ~2x as infectious as original. It may be a bit worse than that.(3/13)
Read 13 tweets
26 Jul
Covid (@UCSF) Chronicles, Day 495

When I began my tweets 494d ago, it was before we had reliable local, US, or world data. So I focused on data from @UCSFHospitals. Today, we’re awash in data, yet I find my hospital's data still provides a unique lens into our situation. (1/20)
So today, a few data points from @UCSF, with my interpretation. They reinforce the case that the combo of Delta & relaxed behavior is leading to a powerful & worrisome upsurge that requires a change in approach. I knew things were bad, but it’s even worse than I thought. (2/20)
What’s particularly noteworthy about @UCSF experience is that it’s in a city w/ the nation’s highest vax rate. And cases are rising fast in our employees, of whom 93% are vaxxed. (Special thanks to Ralph Gonzales, Bob Kosnik & @SaraMurrayMD for some of the data.) Here goes:(3/20)
Read 20 tweets
15 Jul
If you're wondering how bad Delta really is, even in highly vaccinated SF (76% of >age 12 fully vaxxed) & still w/ a lot of masking (most folks in stores), we're seeing a pretty steep Covid uptick. Daily cases up 4-fold (10->42; Fig L), hospital pts doubled (9->19; R)(Thread 1/4) ImageImage
Uptick mirrored @UCSFHospitals: Covid inpatients (we were at ~3 pts two-wks ago) now 13 (Fig L). Overall test positivity rate was well below 1%; it's now up to 2.6% (Fig R). Even more worrisome, test positivity rate in asymptomatic pts was ~0.15%, now up 6-fold to 0.9%. (2/4) ImageImage
I don't have vaccinated/unvaxxed breakdown for SF & UCSF – I assume most severe cases are in unvaxxed. But even for vaxxed, w/ more Covid in air expect more breakthru cases. As for me, I'm back to double-mask in stores. Still indoor dining but might abort if trends continue.(3/4)
Read 4 tweets
13 Jun
Covid (@UCSF) Chronicles, Day 453

1/ I know everybody’s sick of playing 3-dimensional Covid chess. Sorry, but the Delta variant forces us back to the chess board. Ergo, this 🧵.
If you’re fully vaxxed, I wouldn’t be too worried, especially if you’re in a highly vaxxed region.
2/ If you’re not vaccinated: I’d be afraid. Maybe even very afraid.
Why? Let’s start with the things that we know about the current situation, then layer in new information about the Delta (aka, Indian) variant, B.1.617.2 Then we’ll end with what I’d suggest you, and we, do.
3/ Current U.S. situation is good. Cases, hospitalizations, & deaths are falling fast, largely due to our fabulous vaccines. In SF – w/ 70% of people aged >12 fully vaxxed – we’re nearly in a post-Covid world. Everybody’s opening up, including (on Tues) CA. That’s fine…for now.
Read 25 tweets
18 May
1/ Covid @UCSF Chronicles, Day 426

I’ve been letting the new CDC guidelines marinate for a few days, getting over the shock of seeing an agency that’s usually a trailing indicator so “out there.” I tried, but I can’t talk myself out of seeing the new recs as too far, too fast.
2/ This afternoon, my state of California rendered the same judgment, delaying the lifting of indoor masking requirements until June 15th. The extra month will make a big difference – it’ll give folks who just got access to vaccines in April & May time to get fully vaccinated…
3/ … and also afford 12-15 year-olds a chance to be vaccinated. It also means – if the projections are right – that there will be far less virus in the air by mid-June, which will make indoor activities safer, even if some unvaccinated people take off their masks.
Read 25 tweets
18 Apr
Yesterday’s @WashingtonPost piece on flying-after-vaccination, in which I said I won’t eat on an airplane, created a bit of a kerfuffle.… Even @natesilver538 weighed in today.

Let me explain my thinking. (A 🧵) (1/25)
I am fully vaccinated (2 doses of Pfizer in Dec/Jan). As such, I consider myself exceedingly unlikely to get very sick and die from Covid, though as the number of vaccinated people grows, we are beginning to hear about a few breakthrough infections.… (2/25)
Most breakthrough infections are mild but there are rare ones that are serious. Of >75M people fully vaxxed as of 4/13, CDC has logged 5814 breakthrough infctns (documented Covid post-full vaccination). That’s not surprising. As we know, the vaccines aren't 100% protective.(3/25)
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4 Apr
1/ Covid (@UCSF) Chronicles, Day 383

Perhaps the most confusing time since the start of the pandemic – its easy to be overwhelmed. I’ll try to make sense of some of the key trends, particularly the “4th surge” & vaccines vs variants.

Bottom line: I’m still leaning optimistic.
2/ Part of my optimism stems from where I live: Covid stats in San Francisco are excellent. Let’s start w/ @UCSFHospitals, where there are 7 Covid pts (vs. ~100 in January), & only one on a vent (Fig L). Test positivity is 0.9%; 0.4% in asymptomatic patients (R). Pretty darn low. ImageImage
3/ SF overall is also good: 37 cases/day in city of 875K, maybe a tiny uptick in past few days (Fig L). Only 21 Covid pts in all SF hospitals (vs. 259 in January; R). And only 6 Covid deaths in SF in past 4 weeks; total deaths remain <500 for pandemic. Test positivity also 0.9%. ImageImage
Read 25 tweets
19 Mar
1/ Covid (@UCSF) Chronicles, Day 366

My first "Chronicle” was March 18 2020. Today, I've chosen to look back on the early days of this singular year, both terribly saddened by the incalculable losses – especially since so many were preventable – yet optimistic about the future.
2/ And not just optimistic about Covid. I think we’ll emerge as a better, stronger society, with more attention being paid to people in need, a broader set of tools for and approaches to attacking important problems, and a far higher chance of being prepared for the next threat.
3/ My March 18 2020 tweets are here: For many folks – scared & stuck at home – it was the first pandemic look inside a big hospital. @UCSF, to its credit, allowed a level of transparency that served our community well in coming mths. It was the right call.
Read 25 tweets
10 Mar
1/ Covid (@UCSF) Chronicles, Day 357

I’ve taken a little break from my threads – Covid is slowing down (yippee!) & I’ve gotten busy hosting @inthebubblepod. Thanks for your patience.

Today, I’ll update numbers, take a deeper dive into new CDC recs, & cover a few odds & ends.
2/ @ucsfhospitals, marked improvement. Today, 18 pts, 4 on vents (Fig L). (On 1/12, #s were 102/24.) Test positivity also way down: now 0.7% overall – 3% in pts w/ symptoms, 0. 4 in pts w/ no symptoms (Fig R). Thus, asymptomatic person in SF has ~1-in-250 chance of having Covid.
3/ Keep this low prevalence in mind in considering safety of activities. Remember, chance of catching Covid not only relates to riskiness of activity (eating inside, going to gym, etc) but also to odds that nearby person has Covid. Based on UCSF, it’s pretty low in SF right now.
Read 25 tweets
23 Feb
1/ Covid (UCSF) Chronicles, Day 342

A confusing time, with dueling narratives – one optimistic (Vaccines! Falling cases! @ASlavitt! Warmer weather!); the other pessimistic (Variants! Letting guard down!).

First a review of local scene. Then, why I mostly side w/ the optimists.
2/ Improvement in numbers is truly striking, w/ cases, test positivity & hospitalizations all plummeting. @UCSFHospitals: 42 cases, 11 vented (Fig L). Better yet: test positivity=1.7%: 6.2% in symptomatic pts, 1.1% in asymptomatics (Fig R). While these # s are much better than…
3/ …last mth, they still mean an asymptomatic person in SF has ~1/100 chance of having Covid (based on the 1.1% rate in our patients w/o symptoms).

So don’t let your guard down, particularly since – if you haven’t been vaccinated yet – you’ll get a chance in the next 3 months.
Read 25 tweets
19 Feb
In early January, @ashishkjha & I made case for delayed 2nd dose in @washingtonpost In last few weeks, @mtosterholm, Stanley Plotkin, & now @ZekeEmanuel have come out in support of this strategy. To be clear, we appreciate the counterarguments,... (1/4)
...particularly the messaging challenges (will some people forego 2nd dose?). But with the rapid spread of B117, the case for calling an audible for next 2 months & getting more people their 1st dose of Pfizer or Moderna has grown stronger. And this case is now bolstered (2/4)... real-world data from Israel @thelancet (1st dose 85% effective in preventing symptomatic Covid) & @NEJM (review of original @US_FDA data: 1st dose 92.6% effective)

Time's a wasting – increasingly clear that...(3/4)
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12 Feb
1/ Covid (@UCSF) Chronicles, Day 331

Today, UCSF Medicine Grand Rounds. I'll start w/ quick update on local scene & then review the terrific presentation on vaccines and masks by @monicagandhi9. The entire 75 minute conference is here – worth watching:
2/ While I’ll cover Monica’s presentation in this thread, there's more. At 39:30 Marguerita Lightfoot, chief of Division of Prevention Sciences, discussed vaccine hesitancy in communities of color. At 52:00, Robert Rodriguez, @UCSF Prof. of Emergency Medicine, & @DrEricGoosby
3/ @UCSF Professor of Medicine & former UN Special Envoy on TB, discussed their experience on President Biden’s Covid-19 Advisory Board. Just as @Atul_Gawande told me @inthebubblepod, Rob & Eric were impressed by the Biden team,….
Read 25 tweets
10 Feb
1/ Covid (@UCSF) Chronicles, Day 329

So many competing forces & trends. As dramatic as a thriller, but very decidedly – and tragically – as real as it gets. Everything's leading up to a decisive moment in late March, when we see if we’ve won or lost The Race vs. the variants.
2/ More on that after update on local/nat'l situation. Not bad, tho the usual caveat – while far better than last mth, these are still very high case counts, test positivity rates, & hospitalizations – much higher than the peaks of last summer. Covid-wise, it’s still pretty hot.
3/ @ucsfhospitals, 47 pts, 13 vents (Fig L) – I'm still concerned w/ plateau, but hospitalizations are a lagging indicator. Reassured that test positivity rates are falling – now 2.4% overall, down >50% over last month. Test positivity in asymptomatic pts: down to 1.4% (Fig R).
Read 24 tweets
3 Feb
1/ Covid (@UCSF) Chronicles, Day 322

Today, an update on local situation. Then my take on a few issues of the day. There’s some great news, some good news, & some bad news (in the form of variants, lurking just over our horizon). I think we can win The Race, but it’ll be close.
2/ Let’s start w/ local situation & then move out – themes are pretty consistent across U.S. @UCSFHospitals, 50 pts in hospital, 13 on vents (Fig L). Test positivity 3.8%; 9.3% in pts w/ symptoms, 2.6% in asymptomatics (Fig R). While hospitalizations & test positive rates are...
3/ … down 30-50% over past 2 wks, I worry that the curves are now a bit plateaued. (After past surges, once cases/test positivity rates started falling they continued to do so.) While I think we'll keep getting better, this bears watching.
Read 25 tweets
29 Jan
1/ Covid (@UCSF) Chronicles, Day 317

Today was medical grand rounds: brief summary below but worth watching for latest on vaccine distribution in SF, current state of the pandemic, & the variants – overall & with a specific focus on the UK. It’s here:
2/ We began w/ Susan Philip, acting health officer @SF_DPH, talking about vaccine roll-out in San Francisco. As expected, as distribution has improved the problem is increasingly “supply, supply, supply.” Goal: to vaccinate 10,000 people per day in SF. Three pronged strategy: …
3/ …high-volume vaccination sites, community pharmacies, & smaller community-based sites (mobile hubs, clinics). @UCSFHospitals & other healthcare systems helping (we’re running big site @CityCollegeofSF). Plan is to be provider agnostic (pts can go to any site to get vaccine).
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22 Jan
1/ Covid (@UCSF) Chronicles, Day 310

What a joy watching Fauci's press conf. today. Last yr must have been torture for him, a brilliant man of great integrity. How liberating to speak truth w/o looking over his shoulder, & how uplifting to listen to him!
2/ At 11:40, Fauci says, “One of the things that we’re going to do is be completely transparent, open, and honest. If things go wrong, not point fingers but correct them, and to make everything we do based on science and evidence.” Hallelujah!…
3/ Today a brief update on the local & CA situation, and a few comments on the two big issues: the vaccine roll-out and the variants.

The bottom line is that we’re turning a corner on the winter surge, at UCSF, in SF, in CA, and in the U.S. Things are still pretty bad…
Read 22 tweets
19 Jan
1/ Covid Chronicles, Day 307

One of the most challenging parts of Covid has been grappling with decision-making under uncertainty. It’s natural for MDs to weigh risks & benefits; med school trained us in probabilistic decision-making. But it’s an unnatural act for most people.
2/ And it's even harder w/ Covid. Just as you’ve gotten comfortable with a situation – Should I go to the store? Have a drink outside w/ friends? – the numbers change.

So let’s take a few minutes to go through some math – the kind of math you need to make rational choices.
3/ Let’s start w/ a basic tenet of decision-making in Covid: there is nothing that's perfectly safe, & nothing that's totally risky. Everything is about probabilities. What do I mean? A good cloth mask isn’t 100% effective, but it does lower chances of getting infected by 70-80%.
Read 25 tweets