So, to be clear, his all-things-considered view is about 1.5k uCOVIDs cost an hour, which is toward the edge of my range that corresponds to high risk, while his numerical estimate is at 7.5k uCOVIDs costing an hour, which is just outside of my range that corresponds to low risk (but matches almost exactly with my estimates of Long COVID risk outside of follow-ons from cognitive impairment!). So it sounds like initially he disagreed toward higher risk, then found very similar numbers as I did, now only leans toward the high end of my risk estimate due to priors and right-tail uncertainty. (Apologies if my paraphrase does not do your view justice, Adam.)
This is an accurate summary, thanks! I’ll add my calculation was only for long-term sequelae. Including ~10 days cost from acute effects, my all-things-considered view would be mean of ~40 days, corresponding to 1041 uCOVIDs per hour.
This is per actual hour of (quality-adjusted) life expectancy. But given we spend ~1/3rd of our time sleeping, you probably want to value a waking-hour at 1.5x a life-hour (assuming being asleep has neutral valence). If you work a 40 hour work week and only value your productive time (I do not endorse this, by the way), then you’d want to adjust upwards by a factor of (7*24)/40=4.2.
However, this is purely private cost. You probably want to take into account the cost of infecting other people. I’m not confident in how to reason about the exponential growth side of things. If you’re in a country like the US where vaccination rates have plateaued, I tend to expect Delta to spread amongst unvaccinated people until herd immunity is reached. In this scenario you basically want infection rates to be as high as possible without overwhelming the healthcare system, so we get to herd immunity quicker. (This seems to actually be the strategy the UK government is pursuing—although obviously they’ve not explicitly stated this.) But if you’re in a country that’s still actively vaccinating vulnerable people, or where flattening the curve makes sense to protect healthcare systems, then please avoid contributing to exponential growth.
Neglecting the exponential growth side of things and just considering immediate impact on your contacts, how likely are you to transmit? I’d be surprised if it was above 40% per household contact assuming you quarantine when symptomatic (that’s on the higher end of transmission seen even with unvaccinated primary cases), but I’d also be surprised if it was below 5% (lowest figure I’ve seen); I’d guess it’s around 15% for Delta. This means if you have ~6-7 contacts as close as housemates, then your immediate external cost roughly equals your private cost.
Specifically, two studies I’ve seen on secondary attack rate given vaccination (h/t @Linch) give pretty wildly varying figures, but suggest at least 2x reduction in transmission from vaccination. Layan et al (2021) found 40% of household contacts of Israeli medical staff developed an infection (when Alpha was dominant), with vaccination of the primary case reducing transmission by 80%, so an 8% chance of transmission overall. Harris et al (2021) from Public Health England suggest vaccination cuts transmission risk from 10% to 5%, but these figures are likely skewed low due to not systematically testing contacts.
According to this specific calculation. He does say his all things considered view is like 5x the cost.
So, to be clear, his all-things-considered view is about 1.5k uCOVIDs cost an hour, which is toward the edge of my range that corresponds to high risk, while his numerical estimate is at 7.5k uCOVIDs costing an hour, which is just outside of my range that corresponds to low risk (but matches almost exactly with my estimates of Long COVID risk outside of follow-ons from cognitive impairment!). So it sounds like initially he disagreed toward higher risk, then found very similar numbers as I did, now only leans toward the high end of my risk estimate due to priors and right-tail uncertainty. (Apologies if my paraphrase does not do your view justice, Adam.)
This is an accurate summary, thanks! I’ll add my calculation was only for long-term sequelae. Including ~10 days cost from acute effects, my all-things-considered view would be mean of ~40 days, corresponding to 1041 uCOVIDs per hour.
This is per actual hour of (quality-adjusted) life expectancy. But given we spend ~1/3rd of our time sleeping, you probably want to value a waking-hour at 1.5x a life-hour (assuming being asleep has neutral valence). If you work a 40 hour work week and only value your productive time (I do not endorse this, by the way), then you’d want to adjust upwards by a factor of (7*24)/40=4.2.
However, this is purely private cost. You probably want to take into account the cost of infecting other people. I’m not confident in how to reason about the exponential growth side of things. If you’re in a country like the US where vaccination rates have plateaued, I tend to expect Delta to spread amongst unvaccinated people until herd immunity is reached. In this scenario you basically want infection rates to be as high as possible without overwhelming the healthcare system, so we get to herd immunity quicker. (This seems to actually be the strategy the UK government is pursuing—although obviously they’ve not explicitly stated this.) But if you’re in a country that’s still actively vaccinating vulnerable people, or where flattening the curve makes sense to protect healthcare systems, then please avoid contributing to exponential growth.
Neglecting the exponential growth side of things and just considering immediate impact on your contacts, how likely are you to transmit? I’d be surprised if it was above 40% per household contact assuming you quarantine when symptomatic (that’s on the higher end of transmission seen even with unvaccinated primary cases), but I’d also be surprised if it was below 5% (lowest figure I’ve seen); I’d guess it’s around 15% for Delta. This means if you have ~6-7 contacts as close as housemates, then your immediate external cost roughly equals your private cost.
Specifically, two studies I’ve seen on secondary attack rate given vaccination (h/t @Linch) give pretty wildly varying figures, but suggest at least 2x reduction in transmission from vaccination. Layan et al (2021) found 40% of household contacts of Israeli medical staff developed an infection (when Alpha was dominant), with vaccination of the primary case reducing transmission by 80%, so an 8% chance of transmission overall. Harris et al (2021) from Public Health England suggest vaccination cuts transmission risk from 10% to 5%, but these figures are likely skewed low due to not systematically testing contacts.