looking at Mark Handley's graphs of many countries evolution of the pandemic, and the interventions, i'm going to engage in some idle speculation - please don't take this seriously or as a prediction - its just thinking out loud...
people see family multiple times a day
people make daily trips home->work/school
people make weekly trips (home->shops or trips to country)
people make monthly trips (business -> other countries)
this pattern of self-similar journeys underlies this study of cinter-ontact intervals and duration.
If you look at clustering starting in Wuhan, and then to rest of china, then to other country, it really looks like that. Rhyhm and randomness in human movements as also explored in this ref paper.
It seems that in a trip you might meet 1-100 people but only infect 1-2 so its quite hard for most people to catch, but somewhat easy for some
(severity is a whole other question, maybe, but maybe its related too)
Baseline:
35% daily increase corresponds to a doubling time of 2.5 days
assume basic R0 is 2-3 -i.e. as above, so each person adds 1-2 people a day
but they aren't necessarily infectious for 3-5 days so you get double every 2-3 days
Social Distancing
22% daily increase corresponds to a doubling time of 3.5 days
distancing works weakly - i.e. your infectious person travels
more carefully in their daily trips but not carefully enough. see this LSHTM paper for more info which looks consistent?
Speculate - if Covid-19 can be spread by touch, this might be
evidence that 2 meter is fine if everyone washes every time they were near where an infected person touched. so maybe combination of masks and washing would be as good as lockdown if 100% observant, but if 50% obvservant, only roughly halves the spreading rate.
Lockdown...works:
13.5% daily increase corresponds to a doubling time of 5.5 days
lockdown week 1 < works, but you've only removed half the people in the first week
8% daily increase corresponds to a doubling time of 9 days
lockdown week 2, remove other half....but still have tail of who was infected 2 weeks back, showing symptoms this week
0%
lockdown week 3?
people see family multiple times a day
people make daily trips home->work/school
people make weekly trips (home->shops or trips to country)
people make monthly trips (business -> other countries)
this pattern of self-similar journeys underlies this study of cinter-ontact intervals and duration.
If you look at clustering starting in Wuhan, and then to rest of china, then to other country, it really looks like that. Rhyhm and randomness in human movements as also explored in this ref paper.
It seems that in a trip you might meet 1-100 people but only infect 1-2 so its quite hard for most people to catch, but somewhat easy for some
(severity is a whole other question, maybe, but maybe its related too)
Baseline:
35% daily increase corresponds to a doubling time of 2.5 days
assume basic R0 is 2-3 -i.e. as above, so each person adds 1-2 people a day
but they aren't necessarily infectious for 3-5 days so you get double every 2-3 days
Social Distancing
22% daily increase corresponds to a doubling time of 3.5 days
distancing works weakly - i.e. your infectious person travels
more carefully in their daily trips but not carefully enough. see this LSHTM paper for more info which looks consistent?
Speculate - if Covid-19 can be spread by touch, this might be
evidence that 2 meter is fine if everyone washes every time they were near where an infected person touched. so maybe combination of masks and washing would be as good as lockdown if 100% observant, but if 50% obvservant, only roughly halves the spreading rate.
Lockdown...works:
13.5% daily increase corresponds to a doubling time of 5.5 days
lockdown week 1 < works, but you've only removed half the people in the first week
8% daily increase corresponds to a doubling time of 9 days
lockdown week 2, remove other half....but still have tail of who was infected 2 weeks back, showing symptoms this week
0%
lockdown week 3?
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