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1/ The key – & challenge – to stopping #COVID19 is finding & breaking off enough asymptomatic/presymptomatic transmission. This ‘invisible’ spread seems to be driving the epidemic & making it difficult to control. https://www.nejm.org/doi/full/10.1056/NEJMoa2008457
2/ Testing symptomatic pts alone won't find enough transmission chains
To stop more ‘invisible’ spread, we need to (1) test more widely w/tracing (2) when test+trace is better, replace social distancing w/social protection (ie masks, spacing) to protect against spread in public
To stop more ‘invisible’ spread, we need to (1) test more widely w/tracing (2) when test+trace is better, replace social distancing w/social protection (ie masks, spacing) to protect against spread in public
3/ If testing were unconstrained, we could test everyone weekly for 2 consecutive wks. This would offset false-negatives, cover incubation period & find virtually all transmission chains.
4/ We could then use isolation & contact tracing to follow out each chain to its end. The epidemic would be over in several weeks unless reseeded from abroad.
5/ We are at least an order of magnitude away from the testing needed to do this. To do this for NYC alone would require 16m tests. The recent doubling to 300K per day is progress but still not in the ballpark.
https://covidtracking.com/
https://covidtracking.com/
6/ Even w/o mass testing, we can test more widely & strategically to potentially find enough asymptomatic/presymptomatic transmitters.
Scaled up contact tracing can help identify more people who may have ‘invisible’ infections. https://www.npr.org/2020/04/27/845165404/ex-officials-call-for-46-billion-for-tracing-isolating-in-next-coronavirus-packa
Scaled up contact tracing can help identify more people who may have ‘invisible’ infections. https://www.npr.org/2020/04/27/845165404/ex-officials-call-for-46-billion-for-tracing-isolating-in-next-coronavirus-packa
7/ At current infection & testing levels, testing symptomatics + contacts may still not find enough asymptomatic/presymptomatic spreaders to get R<1.
8/ We don’t have enough testing to even do this right now.
We could presumptively isolate contacts for the 14-day incubation period w/o testing or better target testing to population subgroups that could be higher yield which may vary based on local transmission patterns.
We could presumptively isolate contacts for the 14-day incubation period w/o testing or better target testing to population subgroups that could be higher yield which may vary based on local transmission patterns.
9/ Until there is enough testing, only way to safely relax lockdowns would be to couple #TestTraceIsolate w/social protection measures that block transmission.
These measures should mimic what more social distancing does w/o same degree of social, economic & health damage.
These measures should mimic what more social distancing does w/o same degree of social, economic & health damage.
10/ Social protection measures are unlikely to be as effective as social distancing but could enable us to keep R<1 w/o lockdowns with more testing + tracing but not as much as would be needed otherwise.
11/ As we ramp up testing + tracing, we should put as much focus, rigor, innovation & urgency on figuring out the protective measures that work best & innovating ways to make them more effective & scalable (i.e., commercial high-filtration masks).
