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What do we need to know and do about Delta variant COVID in the SF Bay Area?

Published on 2021-07-25 as a Facebook post.

The Bay Area has a big wave of Delta COVID starting. What do we need to know
and do about it? A thread 🦠 💉😷 🙂

Screenshot showing the emergence of a rapidly growing fourth wave of COVID-19 in the SF metro as of 2021-07-25

  1. How big will this wave be? Large. It's going to get most of the children and unvaccinated adults in the Bay Area. It's also probably going to infect a good portion of us vaccinated people too, perhaps 7 - 30% of us but the error bars are wide depending on the precautions we take and whether you believe the CA/UK or Israeli studies on vaccines and Delta.

  2. What is the Delta strain? How bad is it? Delta is generally a nastier version of COVID in many respects. With much higher viral loads, it spreads more and faster. It has been documented to spread outdoors a bit more often (still less than indoors), and probably more in fomite form too. Australia, China, Taiwan, Vietnam, etc were able to repeatedly eliminate previous covid strains with lockdowns and contact tacing, but Delta looks like it might overwhelm those response systems.

    Fortunately, the vaccines still work really well for Delta. Large reductions in inbound and onwards transmission, and very large reductions in severe disease. If you've had one shot of J+J, a second shot of something (J+J or an mRNA vaccine) is probably a good idea and now being advocated by some immunologists.

    In terms of severity for unvaccinated people, Delta has about 2x higher rates of hospitalisation and death. We don't know about rates of long COVID, which is probably the most important question.

  3. What precautions should we take? I would recommend minimizing what you do indoors in public, and wear a mask when you're doing things indoors. Dine outdoors rather than indoors. If you're going to a party, wear a mask! (and maybe as the wave gets big, avoid parties for a few weeks).

  4. Will or should we collectively go back to lockdown? Not for now, and probably not at all. We've had time to vaccinate here, and we don't need to shut down society to protect people who don't want to be helped. Maybe if the wave gets way bigger and Bay Area's hospitals are close to overflowing, a short shelter-in-place might make sense to save unvaccinated lives.

  5. How dangerous is this situation? For most of us who are healthy and fully vaccinated, this wave will be like a bad regular flu season. However if you're either unvaccinated or immunocompromised, or have other extensive risk factors, it's a different story.

    If you're in one of those categories, I would recommend sheltering on your own or in a small pod until this has passed.

  6. If you're unvaccinated, get a shot now. But there may not be enough time for it to kick in given how much covid will be around next week. Get vaccinated, but take cover from this wave anyway.

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