1. Some hard facts to explain why
Testing, testing, testing is not enough
In our @RockefellerFdn action plan we called for 35 million tests/week, scaling up over the next 6 months https://www.rockefellerfoundation.org/national-covid-19-testing-action-plan/ Others have called for 35 million/day

2. We need a massive number of tests now, daily, but it has taken the US several weeks just to get to <5 million total. Even with the recruitment of academic & industry labs (as we advocated), it'll take time & the big N of tests, while desirable, are ambitious, to say the least.

3. Besides practical limitations of doing tests for >330 million people, once is not enough. A negative test could turn positive the next day. There is a major issue still w/ false negatives. Testing every week (or more frequent) would be ideal, but that's even more impractical.

4. Relying on the serology tests sets up other problems. There is a significant false positive rate and lack of validation of any at scale, especially in populations w/ low infection rates.
Moreover, we don't know if IgG antibody protects: (1)against spread and (2) for how long?

5. So now test, test, test has some holes. We desperately need to do them but can't do them at the scale or frequency we need for the US population and geography; the accuracy can't be fully relied upon. The virus test is a one-off assessment. How can we be smarter about this?

6. We need massive, passive, cheap, continuous surveillance for risk.
We've seen promise w/ a smart thermometer ( @Kinsa) but that requires taking one's temperature a couple of times a day.
There are >100 million Americans w/a smartwatch or wristband that gets resting heart rate.

7. A rise in resting heart rate antedates fever; we've published on its ability to predict flu:
https://www.thelancet.com/journals/landig/article/PIIS2589-7500(19)30222-5/fulltext
Germany ( @rki_de) used that to design a smartwatch app for heart rate now used for >300,000 citizens for #COVID19 surveillance

8. We have no national #COVID19 plan. If we did, we'd have a digital surveillance strategy, as reviewed @RockefellerFdn report. In the meantime, you are welcome to join >12,000 Americans enrolled in @detect_study to donate your heart rate data. Spread the word, not the virus.