Thread by @Bob_Wachter

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.

4/ I won’t review the SF, CA, & U.S. numbers in detail – they're also impressively better, pretty much everywhere (Fig). Why? Just as surges represent a perfect storm of bad conditions (followed by a vicious cycle of more cases begetting more cases), coming out of a surge…

5/ … is the mirror image, w/ many things going right: growing levels of immunity; more adherence to the public health recs; no more big holiday mixers. And then cases & test positivity rates fall, so the same activity (e.g., eating w/ friends) carries far less risk than before.

6/ The drop in cases is awesome, but it comes at a time of incalculable sorrow, as we reach 500,000 dead in the U.S. It was at about this time in 2020 when the earliest signs that Covid-19 would lead to unprecedented levels of loss were emerging… nytimes.com/2021/02/21/ins…

7/ …but few among us (certainly not me) anticipated a toll of a half-million dead – equal to populations of Atlanta or Kansas City. So many of the deaths could have been prevented had we come together under real leadership in 2020. One only hopes that this lesson's been learned.

8/ But we’re now in a far better place. News on vaccines – both efficacy & safety – is ever more positive, now supported by real world data. In my interview w/ @DrPaulOffit @inthebubblepod last month, Paul made the point that efficacy & effectiveness … podcasts.apple.com/bh/podcast/too…

9/ …aren’t the same thing, since real world effectiveness results often differ from results seen in the controlled environment of clinical trials. For Covid vaccines, though, the more we learn – particularly from Israel's experience – the better it looks.
bloomberg.com/news/articles/…

10/ And the safety data is equally reassuring. After those early reports of severe allergic reactions, we now know that such reactions occur in 1 in ~250,000 vaccinations, & there are few signs of serious long-term problems despite >10M vaccinations. nature.com/articles/d4158…

11/ On top of that, January's botched roll-out has mostly been fixed. Whereas a month ago, we were only injecting 30% of vaccine doses being stored in local freezers, we’re now up to ~80% in U.S.

Distribution is no longer the bottleneck, it’s now supply.
tinyurl.com/yyp3mj79

12/ And the supply is growing fast, helped by the extra doses from each Pfizer vial, more purchases by U.S. govt (along w/ new $4B commitment for global vaccines) & the very likely approval of J&J vaccine next wk. All of this means that we could quickly… tinyurl.com/45dmk3bw

13/ … toggle from today's vaccine shortage to, by April, a shortage of arms. This – plus the increasingly robust evidence that the first dose of Pfizer/Moderna is ~85% protective – supports the case for giving more 1st shots, & delaying 2nd shots, until the supply is ample.

14/ As @mtosterholm now frames it: if each of your parents was unvaccinated & you had 2 vaccine doses to give, would you give both to one parent? Or one dose to each? The math isn’t hard – it would be far better to protect both at 85% than one at 95%.

https://twitter.com/FiringLineShow/status/1362862193574879232

15/ But I doubt the govt will do this. Why? Because it will be a messaging challenge – some people will think they don’t truly need dose 2, which is wrong. Moreover, as vaccine supply improves & cases fall, burning platform to change things & delay 2nd doses grows a bit less hot.

16/ An easier call: withhold 2nd doses in people w/ documented prior Covid. The studies supporting this strategy grow increasingly persuasive: levels of immunity after a single dose in those with prior Covid equal or exceed those achieved after 2 doses in uninfected people.

17/ While Fauci called these results “impressive,” he's not yet ready to pull the trigger. While we review the science, I'd favor delaying 2nd shots in those w/ past Covid. The key will be sorting out the logistics of antibody testing – tricky but do-able.tinyurl.com/ymstx533

18/ Even the news on variants is less dire. As @EricTopol points out, cases in So. Africa are falling, supporting the premise that the variant's immune escape (which is scary) may not be linked to greatly increased infectivity/spread. That’s comforting.

https://twitter.com/EricTopol/status/1363551912021221377

19/ Also reassuring: per @youyanggu, while prospect of UK variant becoming >50% of US cases is scary, it’s a bit of a statistical artifact when overall cases are falling. tinyurl.com/1l8jf6bz Also, UK’s falling case # s (Fig) shows ability to control surge despite the variant.

20/ So there’s great cause for optimism: more vaccines (J&J); more doses (~1.6M/day); better distribution; perhaps new 2nd dose policies that augment supply. Plus 100M people w/ infection-induced immunity (which seems durable, judging by tiny number of reinfections after 1 yr),…

21/ … and now 13% of U.S. population is 85% protected via 1st dose, and 6% at 95% via getting 2 doses.

At this pace, we're closing in on half of U.S. adults being protected now; & ~60% by late-March, which should put us in a good position to win the race against the variants…

22/ …particularly if So. African & Brazilian variants don't become major factors in the U.S. And by April, weather will warm up. All of this means there’ll be a lot of downward pressure on cases. So while we might see a mini-surge, I expect we’ve seen our last big one. Amen.

23/ @MartyMakary argues we'll hit herd immunity in April. I doubt it. There’ll still be plenty of Covid & sadly many folks won’t take vaccine when time comes – some dissuaded by misinformation; others thinking they no longer need vaccination as cases fall.tinyurl.com/1co2urc3

24/ It’ll be crucial that we keep up our efforts to promote accurate information about the vaccines & the ongoing and very real risks from Covid. We also need to talk about the vaccine's benefits more positively, as you’ll hear on today’s @inthebubblepod, on which I grill…

25/…@Farzad_MD & @cmyeaton about the stuff that vaccinated people CAN now do safely, including hanging out w/ other vaccinated folks, haircuts, & hugging their grandkids. Highly illuminating.

On this sad day, optimism seems odd. But it matches the facts.tinyurl.com/1f7y6fx7