I think one of the big differences with Matt Bell’s estimate is that the UK study catches asymptomatic cases, so you don’t need to discount for initially asymptomatic vs initially symptomatic cases:
So far my favorite source on this information is a UK study that actually has a control group and prospectively and repeatedly surveys a random sample of people in conjunction with providing regular COVID tests so that it actually catches asymptomatic cases. This study was conducted prior to vaccination and prior to the dominance of the delta variant.
The risk difference for self-reported symptoms 5+ weeks was already ~20% for 25-34 year olds. See this figure, from this page.
This (50% reduction), plus his estimate being for Delta rather than Omicron (50% reduction) could explain most of the differences with your estimates, about 10x lower.
If you use this base figure for your estimates, and don’t adjust for initially asymptomatic vs symptomatic cases, then you’d roughly double your risk estimates.
I think one of the big differences with Matt Bell’s estimate is that the UK study catches asymptomatic cases, so you don’t need to discount for initially asymptomatic vs initially symptomatic cases:
The risk difference for self-reported symptoms 5+ weeks was already ~20% for 25-34 year olds. See this figure, from this page.
This (50% reduction), plus his estimate being for Delta rather than Omicron (50% reduction) could explain most of the differences with your estimates, about 10x lower.
If you use this base figure for your estimates, and don’t adjust for initially asymptomatic vs symptomatic cases, then you’d roughly double your risk estimates.