Thread by @Bob_Wachter

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)

This superb thread

https://twitter.com/EpiEllie/status/1422595200615133189

by @EpiEllie walks us through the math behind Delta’s threat. With a virus that’s 2.5 times more infectious, levels of immunity that would have tamped down the spread of the old virus are no longer adequate to do so with Delta. (4/25)

Exhibit A: SF. 70% of the population is fully vaccinated, yet cases are 20x what they were in June (Fig). And with more virus around, there’s more exposure to virus, & so it spirals up. Things are even worse in places w/ lower vaccine rates, such as in the great states of…(5/25)

… FL (49% fully vaxxed), TX (44%), & MO (42%)(Fig). In these states, most people are no better protected vs Covid than they were in early 2020. But the virus is 2.5x better at its job of infecting people. Moreover, CDC now feels that Delta Covid cases are more serious too.(6/25)

Nothing stands in isolation. Here in highly vaxxed SF, everybody’s wearing masks – we’re bummed but there’s little pushback. In states where vaccine rates are low & vulnerability is enormous, many leaders & people “don’t believe” in masks. And often in vaccines. Go figure. (7/25)

That's why I’m all for vaccine mandates. As Einstein (may have) said, “Insanity is doing the same thing over & over & expecting a different result.” We’ve tried education, free vax, sympathy, shaming, & incentives. Our future depends on more vaxxing, despite the objections.(8/25)

Even if vax mandates (plus upcoming formal FDA approval nytimes.com/2021/08/03/us/…) turn the tide, it’ll be months before we get to high enough vaccine rates to tamp down the virus. Until then, anything other than universal indoor masking is simply bonkers. (9/25)

Speaking of being unprotected, the next battleground will be over boosters. So much of Covid has pitted individual rights/choices vs. community need. There now seems little doubt that 4 groups will need boosters to deal w/ waning or inadequate immunity from vaccines:... (10/25)

a) Immunocompromised; b) Elders (?age); c) vax w/ J&J; & d) vaxxed >6 mths ago. My read of evidence: it would be reasonable to offer boosters to all 4 groups today – if the only issue was risks vs benefits to them as individuals. But as @EpiEllie explained, as a society… (11/25)

… we should focus on vaxxing unvaxxed people (vs giving booster) if resources were limited.
But, at least in the U.S., they’re not – there’s so much vaccine around that some is being discarded nytimes.com/2021/08/01/us/… (Of course, if we could sort out the logistics, the… (12/25)

… next dose should really go to Africa or India, but that seems unlikely). Given the probable benefit for individuals, not surprised we’re starting to see booster-seeking fibbing & wink-winking. This’ll screw up vaccine tracking, which is bad. Is it unethical? Tough call.(13/25)

Solution: approve boosters for those 4 groups ASAP as long as vax surplus holds (evidence seems persuasive that benefits outweigh risks), as several European countries have done. washingtonpost.com/world/europe/c… My guess is that FDA/CDC are also hesitating on boosters because… (14/25)

… they fear that green-lighting them will send message to some vax-hesitant folks that vaccines don’t work. I get that, but these kind of Covid mind games (other: call breakthrough infections “rare” so as not to discourage vax) don’t work & serve to undermine credibility.(15/25)

I’m aware that this entire thread has been a major downer. Believe me, I wanted to get back to normal as much as you do.

One bright piece of news amidst the gloom is that – for reasons clear to no one – Delta appears to peak and fall quickly (here is the UK curve)…, (16/25)

… and perhaps it’ll do the same in the U.S. Great! But to the degree that vaccine or infection-related immunity partly explains the peak-and-fall, we might well see another surge in a few months, whether from waning immunity, a new & nastier variant, or some combination.(17/25)

Is there a way out? Delta is so infectious that the end-game may be near-universal immunity thru vaccination & – mostly in the unvaxxed – infection. The # of deaths in the latter category will be high; truly tragic since – unlike in 2020 – most will have been preventable. (18/25)

It’s obvious what an unvaccinated person should do: get vaccinated ASAP, and stay super-safe until fully vaxxed (remember, shot #1 doesn't protect against Delta the way it used to). Particularly in a high case prevalence region, your chance of catching the virus has… (19/25)

… never been higher, and – while treatments have improved – there’s still a decent chance of a stormy course, including Long Covid, hospitalization, and (depending on your risk factors) death. I’d be afraid. Yes, I'd be very afraid. (20/25)

What should a vaccinated person do? That’s trickier. Everybody’s got to choose their own risk tolerance, which'll depend on your psychological state & your risk factors for a bad outcome. It should also be influenced by local prevalence – your chances of a breakthrough...(21/25)

…infection are much higher if you’re in a place with a high case rate than if you’re in Vermont. And as I’ve said, even though the chances of me dying or being hospitalized w/ Covid are low, they’re not zero. And breakthrough cases of Delta, we now know, can potentially…(22/25)

… be spread to others – mostly unvaccinated (including kids <12) or less well protected people (elderly, immunocompromised). They can also be spread to vaccinated folks (though vaxed-to-vaxed spread likely is truly "rare"). That knowledge has added to my level of caution.(23/25)

As a 63-year-old guy vaxxed w/ Pfizer in Dec-Jan, no booster yet, & living in still-fairly-low prevalence SF, what am I doing? I haven’t cancelled flights, though I will if trip's elective. When I fly, I’m wearing N95 for the whole flight. In indoor spaces (stores, work)…(24/25)

... I’m double masking (cloth/surgical). No more indoor dining, & sadly no more poker w/ vaxxed pals. I’ll peel off protections as cases fall, particularly after my booster.

You’ll make your own choices, but don’t underestimate Delta. As the CDC said, it’s a new war. (25/25)