>Something weird happened in California, where 20% of their tests were coming back positive, then all the sudden 04/04/2020 they started seeing <10% positive tests:
This is not surprising. When tests were scarce, tests would be rationed to those most suspected of infection.
The cases reported per country, or state are only a narrow window into what is actually happening. The most advanced medical testing company in the world, Roche, is Swiss-German so Germany's testing capability relative to most countries is off the charts. Combined with a highly distributed, yet also highly co-ordinated health care system they have been ahead of the curve in testing on every conceivable metric. As a result they have reported relatively high case totals, because they have been doing mass testing for a long time, but very low death rates because this enabled them to effectively isolate cases quickly.
As countries increase their testing capacity it is quite possible some countries (or states) will end up eventually reporting accelerating numbers of diagnoses even if the actual new case rate in the population is falling.
One way to mitigate that is to report only cases requiring hospital admission. This isn't ideal by any stretch, but is a reasonable proxy for the spread of the virus and at least gives a good indication of the impact on the health care system.
> Data from 3 epidemiological studies in the United States show that as many as half of people with COVID-19 infections in care homes were asymptomatic (or pre-symptomatic) at the time of testing
> Data from 5 European countries suggest that care home residents have so far accounted for between 42% and 57% of all deaths related to COVID-19.
But hospital admission cases depends on perceived hospital resources too... if people think going to the hospital is worse than staying at home, or impossible, that will distort conclusions also.
That's true, but is mainly a problem when comparing one country or region with another. Within a region, assuming a roughly stable general perception of hospital capability, it should till give a reasonable indication of the relative rise and fall in numbers of severe cases. I don't know, it's a really hard problem.
I can't figure out what you mean, can I go someplace to get tested and put my mind at ease that I'm not about to die or kill my familymembers? That's the only "relative" that matters here.
This whole thread is about California's roadmap. LA County is something like 25% of the state. Why stop at the USA? With people moving between places, outbreaks anywhere will matter until there's a reasonable vaccine/treatment.
Assuming that's the Abbott 15 minute test, there's only going to be 50,000 of those a day for the near future (and it seems less than that in the immediate future).
That's a big chunk on top of current testing, but probably not enough to make it easy to move forward with a testing based strategy.
This is not surprising. When tests were scarce, tests would be rationed to those most suspected of infection.