Perhaps I am missing something but on the >=1000x criteria, if we target e.g. <1% of people succumbing to the disease over their lifetime (might want to set even lower, in order to make people comply with suggestions—precedent of similar risk reductions and uptake might be worth looking into if not done already), this means we expect people that are not protected to inhale only 10 particles over their lifetime, in expectation (assuming minimum lethal dose of 1 particle)? Asking as that seems like a small degree of environmental spread. I realize that perhaps the reasoning here might be infohazardous, but if not I would be very interested to know more. Or perhaps additional reduction comes from one or more additional measures, such as far UVC, glycol, etc.
Sure — I may be mixing abstractions here, so let me spell out what I had in mind.
A 1000× reduction means that, in expectation, the protected environment has 1/1000 of the relevant airborne particle concentration compared with the outside environment. So if an unprotected person would inhale 1000 relevant particles over some period, a protected person would inhale about 1 over the same period, ignoring spatial variation, time dynamics, leakage events, deposition, behavior, etc.
My intuition was then: if the minimum infectious/lethal dose were effectively 1 particle, and if we wanted lifetime infection/death risk inside the protected space to be below ~1%, then the protected person’s expected inhaled dose would need to be on the order of <0.01 infectious particles over the relevant period. With only a 1000× reduction, that corresponds to an outside unprotected expected inhaled dose of only ~10 infectious particles over that same period.
That seems surprisingly low compared to my own work on mirror bacteria. So I was wondering whether the 1000× target assumes one or more of the following:
the relevant environmental concentrations are expected to be quite low;
the true infectious/lethal dose is meaningfully above 1 particle;
the 1000× PM10 reduction is only one layer, with additional reductions from UV, glycol vapor, surface controls, masks, behavior, etc.;
the target is meant as a practical near-term benchmark rather than a complete risk-reduction target.
So my question is basically: what outside concentration / dose / acceptable-risk model makes 1000× the right threshold?
Perhaps I am missing something but on the >=1000x criteria, if we target e.g. <1% of people succumbing to the disease over their lifetime (might want to set even lower, in order to make people comply with suggestions—precedent of similar risk reductions and uptake might be worth looking into if not done already), this means we expect people that are not protected to inhale only 10 particles over their lifetime, in expectation (assuming minimum lethal dose of 1 particle)? Asking as that seems like a small degree of environmental spread. I realize that perhaps the reasoning here might be infohazardous, but if not I would be very interested to know more. Or perhaps additional reduction comes from one or more additional measures, such as far UVC, glycol, etc.
I don’t quite follow, can you spell out the reasoning a bit more?
Sure — I may be mixing abstractions here, so let me spell out what I had in mind.
A 1000× reduction means that, in expectation, the protected environment has 1/1000 of the relevant airborne particle concentration compared with the outside environment. So if an unprotected person would inhale 1000 relevant particles over some period, a protected person would inhale about 1 over the same period, ignoring spatial variation, time dynamics, leakage events, deposition, behavior, etc.
My intuition was then: if the minimum infectious/lethal dose were effectively 1 particle, and if we wanted lifetime infection/death risk inside the protected space to be below ~1%, then the protected person’s expected inhaled dose would need to be on the order of <0.01 infectious particles over the relevant period. With only a 1000× reduction, that corresponds to an outside unprotected expected inhaled dose of only ~10 infectious particles over that same period.
That seems surprisingly low compared to my own work on mirror bacteria. So I was wondering whether the 1000× target assumes one or more of the following:
the relevant environmental concentrations are expected to be quite low;
the true infectious/lethal dose is meaningfully above 1 particle;
the 1000× PM10 reduction is only one layer, with additional reductions from UV, glycol vapor, surface controls, masks, behavior, etc.;
the target is meant as a practical near-term benchmark rather than a complete risk-reduction target.
So my question is basically: what outside concentration / dose / acceptable-risk model makes 1000× the right threshold?
Thanks, I follow you now.