How should we adjust microCOVID estimates for omicron, boosters, testing?
post by Sameerishere · 2021-12-30T00:15:18.413Z · LW · GW · 1 commentThis is a question post.
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Answers 1 Tornus None 1 comment
As I assess potential New Year's Eve plans with the intent of spending several days indoors immediately thereafter with my parents (early-to-mid 60s, one has mild-to-moderate asthma but probably healthier than your average 60 year old otherwise [1]), I've been struggling to figure out how to use microCOVID.org given Omicron, boosters, and potential rapid testing.
Here are my working assumptions for everything but testing:
https://docs.google.com/spreadsheets/d/1yZqJKyzPu4CuNFfSR7Tq_QFgSEKrNll-n6iFB-Ly4jw/edit?usp=sharing
For rapid tests, I plan to multiply by a factor of 30% based on Tornus' post [LW · GW] citing a 75% reduction in risk from a BinaxNOW test. I cut it down by 5 percentage points arbitrarily to reflect some uncertainty around how sensitivity varies for omicron. Uncertainty comes from the following:
- Preliminary results from the NIH: https://www.politico.com/news/2021/12/28/fda-antigen-tests-reduced-sensitivity-omicron-526217?fbclid=IwAR22ulLUhteXrFdhFiuYMLa35Ha1BXFNT_z4QlA6f6ql3nSO8tQ2Q7_WfoU
- Michael Mina explains this means "ALL tests will falter on day 1" (not that rapid antigen tests are uniquely bad), but I imagine that doesn't change the fact that rapid tests are less accurate for Omicron?). He notes that UK Gov found no impact on sensitivity for Omicron, but it seems like a lot of tests in the UK recommend throat swabbing, and that could impact accuracy for Omicron for tests like BinaxNOW which are nasal only)
- This: https://www.businessinsider.com/how-to-trust-rapid-covid-test-result-2021-12?amp&fbclid=IwAR3pio-S_xkw4uUOL07sy1lYTapjOBGzRm1iHg0Pe0GFL5aJ1NUXpYfmCGs
[1] In practice, I plan to navigate this by doing rapid tests every day I am with my parents, and masking indoors with a KN95 for at least the first day. Still figuring out how risky a gathering I am willing to attend given that (hang out with a few people indoors with rapid tests beforehand? Plus masks?).
Answers
Good questions—thank you for starting this conversation.
Your assumptions about testing seem reasonable, and hopefully we'll have confirmatory data soon.
I have with great regret stopped using microCOVID. A factor of 2 - 3 x risk multiplier seems reasonable, but I no longer entirely trust their transmission model. It's probably still more or less valid, but Omicron is a very different disease. There's some interesting data about it preferring the upper respiratory tract to the lungs, and about how Omicron particles behave differently in aerosols, that make me worry that transmission patterns may have changed in ways that are more complicated than a simple multiplier.
I'm hoping to see more data soon (and especially hoping that the microCOVID team will update for Omicron, although that seems somewhat in question [LW · GW]).
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