4 ms·

With the average adult getting two bouts of common cold each year and mild COVID symptoms resembling a common cold, I'd think a large fraction of the population

With the average adult getting two bouts of common cold each year and mild COVID symptoms resembling a common cold, I'd think a large fraction of the population might think they had it. I wouldn't dear to guess in which way this shifts the estimate. I think it's understood, that with such a small sample size, results are to be taken cautiously. You have to start somewhere though.

cameldrv 7y ago
There was another serological survey of blood donors in Castiglione d'Adda in Italy. That one came up 70% positive. That town had 1.4% of its population die in March. That suggests an IFR of 2%, not counting people who were sick and might die from COVID in April.
- usaar333 7y ago
  We do need to be careful talking about "IFR" as with a disease with such high age-dependence demographic skews heavily alter population IFR. Castiglione d'Adda has more people over 70 than Santa Clara County has over 65; population over 65 is about 60% higher relatively. Population under 18 conversely is about 22% lower. Hard to do the math exactly, but if you simply switch 8.1% of your population from being children to being 80+, you raise IFR by 0.6% per the Imperial College China estimates. Combined with the hospital triaging Italy was doing, I don't think sub-1% IFRs in Santa Clara county are improbable. (though I do think this survey's claims are improbably low) sources: https://www.citypopulation.de/php/italy-localities-lombardia.php?cityid=09801410001 https://www.citypopulation.de/php/italy-localities-lombardia... https://www.census.gov/quickfacts/santaclaracountycalifornia https://www.census.gov/quickfacts/santaclaracountycalifornia https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
  - cameldrv 7y ago
    I agree that you have to make an age adjustment for IFR, and your numbers seem reasonable. However, in the U.S. you also have a lot more diabetes, obesity, and high blood pressure, which are major risk factors. I wouldn't be surprised if that required a bigger adjustment than the age difference.
    - usaar333 7y ago
      Agreed that US as a whole can have a high IFR. Santa Clara county though is one of the healthiest places in the US. Life expectancy of 84 exceeds Italy in fact.
cactus2093 7y ago
Given that testing is still limited and you have to really make a case for yourself to get it, the group of people who have been tested (not for the antibodies, for infection) is at least a lower bound on the people who think they had it. And statewide we have been at around 12% positives, so it's reasonable to say at least 88% of people who think they had it didn't.
SubiculumCode 7y ago
3,330 tests isn't generally considered a small sample

cameldrv 7y ago

There was another serological survey of blood donors in Castiglione d'Adda in Italy. That one came up 70% positive. That town had 1.4% of its population die in March. That suggests an IFR of 2%, not counting people who were sick and might die from COVID in April.

usaar333 7y ago
We do need to be careful talking about "IFR" as with a disease with such high age-dependence demographic skews heavily alter population IFR. Castiglione d'Adda has more people over 70 than Santa Clara County has over 65; population over 65 is about 60% higher relatively. Population under 18 conversely is about 22% lower. Hard to do the math exactly, but if you simply switch 8.1% of your population from being children to being 80+, you raise IFR by 0.6% per the Imperial College China estimates. Combined with the hospital triaging Italy was doing, I don't think sub-1% IFRs in Santa Clara county are improbable. (though I do think this survey's claims are improbably low) sources: https://www.citypopulation.de/php/italy-localities-lombardia.php?cityid=09801410001 https://www.citypopulation.de/php/italy-localities-lombardia... https://www.census.gov/quickfacts/santaclaracountycalifornia https://www.census.gov/quickfacts/santaclaracountycalifornia https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
- cameldrv 7y ago
  I agree that you have to make an age adjustment for IFR, and your numbers seem reasonable. However, in the U.S. you also have a lot more diabetes, obesity, and high blood pressure, which are major risk factors. I wouldn't be surprised if that required a bigger adjustment than the age difference.
  - usaar333 7y ago
    Agreed that US as a whole can have a high IFR. Santa Clara county though is one of the healthiest places in the US. Life expectancy of 84 exceeds Italy in fact.

cactus2093 7y ago

Given that testing is still limited and you have to really make a case for yourself to get it, the group of people who have been tested (not for the antibodies, for infection) is at least a lower bound on the people who think they had it. And statewide we have been at around 12% positives, so it's reasonable to say at least 88% of people who think they had it didn't.

SubiculumCode 7y ago

3,330 tests isn't generally considered a small sample