A few are quickly dismissing serology studies but they're ALL trending in the same direction: 2% to 4% of the population may have already have faced down #COVID19.

LOTS of implications including this one:

**90% of those infected may be asymptomatic**

and that's a GOOD thing
1/

The chart above via @EricTopol does not include the Santa Clara or LA County studies. Eric pegs it at ~40% which is what a lot of us have been operating under.

But note: those 80% #'s might be closer to the truth!
2/

Best way to describe it is to dive into an example. The latest comes from Los Angeles County which currently shows:
- 12,341 cases
- 600 deaths
- 3500 ever hospitalized cases

This put the crude fatality rate at 4.7%.

But enter the NEW serology report:
https://twitter.com/lapublichealth/status/1252326234077487107?s=20
2/

Barbara Ferrer dir of the Los Angeles County Department of Public Health, said: "the study suggests that 0.1 percent to 0.2 percent of people infected by the virus will die, which would make COVID-19 only somewhat more deadly than the seasonal flu."

Everyone's fav topic!
3/

We know that 12K+ people have tested positive in LA County. Let's say twice that many had symptoms but half didn't test to go to the ER.
IF 2.8% of the pop. of LA already have it:
- 24K people with symptoms
- 221K people were infected

90% of #COVID19 cases are asymptomatic!
4/

Now that's probably not the case because the numbers are still coming in and part of those asymptomatic may be pre-symptomatic. But let's say 3x or 4x as many people had symptoms but didn't get tested.
- 48K symptomatic / 221K = 79% asymptomatic
And that's using the LOW 2.8% #
5/

Again, some of the impact of #COVID19 is based on region, demographics, density. Both LA and NYC have BIG populations but:
- LA: 7000 people / sq. mile
- NYC: 25K people / sq. mile
- Manhattan: 69K people / sq. mile

Let's come at this another way...
6/

We know that LA County has hospitalized 3500 people with #COVID19. Let's assume that 15% hospitalization rate is accurate. That brings us to that 24K symptomatic - so that gut check works.

SO - WHAT DOES THIS ACTUALLY MEAN?
7/

1) If 220K to 400K people have already had some touch with #COVID19 there's NO PRACTICAL WAY TO DO CONTACT TRACING with that many people.
2) Best bet now is to secure and protect the most vulnerable
3) We should still practice safe distancing and limit inside crowds
8/

But if 60% to 90% of people who get #COVID19 have NO SYMPTOMS we have just witnessed a complete failure of our scientific community to identify the true impact of this virus.

We should IMMEDIATELY prep to re-open things, protect those most vulnerable and salvage our economy.