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This is an important new finding and one that requires some quick reflections. Thread
We have all been very interested in seroprevalence studies
Why?
Because we& #39;re wondering whether the proportion of the population that has been infected is much larger than we might think
1/n https://twitter.com/NYGovCuomo/status/1253352837255438338">https://twitter.com/NYGovCuom...
We have all been very interested in seroprevalence studies
Why?
Because we& #39;re wondering whether the proportion of the population that has been infected is much larger than we might think
1/n https://twitter.com/NYGovCuomo/status/1253352837255438338">https://twitter.com/NYGovCuom...
If a much larger proportion has been infected, that would be great for two reasons:
1. Disease milder than we think (lower fatality rate, etc.)
2. We are closer to herd immunity than we thought.
2/n
1. Disease milder than we think (lower fatality rate, etc.)
2. We are closer to herd immunity than we thought.
2/n
So far, 270K NYers have been found to be infected. That& #39;s 1.3% of NY State population (of 19.5 million).
We all know that the true rate is much higher? Why?
Because we& #39;ve been under testing!!
How much higher?
I& #39;ve argued that we identify about 1 in 10 folks with COVID19
3/n
We all know that the true rate is much higher? Why?
Because we& #39;ve been under testing!!
How much higher?
I& #39;ve argued that we identify about 1 in 10 folks with COVID19
3/n
Seroprevalence study out today says that the underlying infection rate is 13.9%
That& #39;s about 10X what we& #39;ve identified.
In line with the idea that we& #39;ve been testing only about 10% of infected folks
That& #39;s about 10X what we& #39;ve identified.
In line with the idea that we& #39;ve been testing only about 10% of infected folks
One more important caveat:
The test characteristics matter a lot.
The NYS website doesn& #39;t give out the sensitivity but says specificity between 93% and 100% (huge range).
5/n
The test characteristics matter a lot.
The NYS website doesn& #39;t give out the sensitivity but says specificity between 93% and 100% (huge range).
5/n
So what does this mean?
If we assume 100% sensitivity and 100% specificity (no test is perfect but hey), then 13.9% is right (with CIs).
But what if we assume 100% sensitivity and 93% specificity, then what?
6/n
If we assume 100% sensitivity and 100% specificity (no test is perfect but hey), then 13.9% is right (with CIs).
But what if we assume 100% sensitivity and 93% specificity, then what?
6/n
Then, the underlying prevalence may be closer to 7% and nearly 1 in 2 positive tests are false positives.
Either way, this is NOT consistent with the idea that the true numbers are 40-85X the number of folks diagnosed (as was suggested by Santa Clara study).
7/9
Either way, this is NOT consistent with the idea that the true numbers are 40-85X the number of folks diagnosed (as was suggested by Santa Clara study).
7/9
Recap:
1.3% of NYers have been infected based on testing
Seroprevalence says 13.9% -- or about 10X.
In line with expectations
But it could be as low as 7% (if specificity of test is 93%)
There are a whole host of other issues but....
8/9
1.3% of NYers have been infected based on testing
Seroprevalence says 13.9% -- or about 10X.
In line with expectations
But it could be as low as 7% (if specificity of test is 93%)
There are a whole host of other issues but....
8/9
Sampling issues always important.
But NYS smart enough to tap into the brilliant @nataliexdean so I& #39;m more comfortable.
Seroprevalence from NYS in line with expectations.
This doesn& #39;t say we are missing very large numbers of asymptomic patients...but clearly some
Fin
But NYS smart enough to tap into the brilliant @nataliexdean so I& #39;m more comfortable.
Seroprevalence from NYS in line with expectations.
This doesn& #39;t say we are missing very large numbers of asymptomic patients...but clearly some
Fin
