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Covid-19 at a homeless shelter in Boston: Implications for universal testing

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Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#111

Post by w0utert »

Retric wrote: post #98
w0utert wrote: post #81

Earlier quoted context omitted.

>> Their mortality numbers looked to be about 0.6% early on, but eventually hit 2% a month after the peak with people spending weeks in critical condition. I see this repeated often but this is a misrepresentation of the statistics. Case fatality rate (CFR) is not the same as mortality rate. The CFR is the ratio between deaths and confirmed cases, mortality rate is the ratio between deaths and total number of people…

Mortality rate is population and cause specific. So CFR is a mortality rate, though different than the overall diseases mortality rate. That said, your definition is also in common usage and less ambiguous.

I think it’s fair to assume most people are mostly interested in statistics that give an indication of the likelihood of dying from a Covid-19 infection, which means you would have to look at the infection mortality rate and not the CFR. So in that sense I think it actually would be somewhat comforting if if it turns out many more people have already been infected than previously assumed. But just to be clear, I don’t want to pretend anyone can reliably claim this considering we still don’t have enough data to create models that can be used to approximate infection rates.

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#112

Post by usaar333 »

zzzzzzzza wrote: post #107
usaar333 wrote: post #75

Earlier quoted context omitted.

It is not plausible they caught most cases. Here's the result of randomized testing in Iceland, which also has the virus under control and has done even more testing per capita ( https://www.nejm.org/doi/full/10.1056/NEJMoa2006100?query=fe... ) Randomized testing was still finding 0.6% of the population (outside those otherwise quarantined already) actively infected. This means even in Iceland, less than half of infe…

But you just ignored the evidence from the diamond princess? and meanwhile germany's data points toward a similar conclusion as the south korean data singapore also has a 1.5% deaths/recovered... and it's been higher in the past if you've been following closely (as high as 2%... question is where have all the new cases been coming from?) icelands data could easily be skewed if they avoided a nursing home getting infe…

An average age of 59 on the Diamond Princess (1.8% CFR) is not representative of the general population. This is a substantially more at-risk group.

Germany and Singapore are also missing many infections. A recent serological study in Germany actually argued for 0.4%.

You are correct that IFR is skewed by who the population is and what interventions are done. But then again, so is the often cited flu benchmark (where we have targeted vaccinations of at-risk groups).

(And age is a huge thing to be aware of skewing the data. e.g. the pediatric IFR from covid is on the order of seasonal flu)

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#113

Post by gnulinux »

raphlinus wrote: post #97
bb2018 wrote: post #82

Earlier quoted context omitted.

Do you have a link to that? I'd love to know more about why this would be the case.

Here's my attempt to validate the claim: https://trends.google.com/trends/explore?date=2019-01-01%202... I'll leave it for readers to determine whether it holds up.

So there was 0 searches, then ~90 searches suddenly? Yeah no sounds like just noise. There will always be some people searching about corona viruses, they always existed and we always knew of them.

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#114

Post by casefields »

sjg007 wrote: post #19
drtillberg wrote: post #7

Earlier quoted context omitted.

The Boston Globe this morning ran an op-ed advocating testing a random sample of residents to get a better sense of community-wide infection rates.[1] It's amazing that this needed to be stated in a major market newspaper four weeks after most business and school was stopped due to the virus. Goverent is doing some interesting things, random sampling apparently isn't one of them, for reasons it's hard to understand.…

It's probably low prevalence in the population based on our understanding of when covid-19 first appeared. The UK has some randomized seriological surveillance and it's about 13% prevalence. That matches with the pregnancy study of 15% prevalence (which may be enriched due to hospital visits).

There's already a change in the public narrative.

New signs suggest coronavirus was in California far earlier than anyone knew: https://www.latimes.com/california/story/2020-04-11/bay-area...

Whoops.

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#115

Post by LatteLazy »

jcp2fa wrote: post #6

> Cough (7.5%), shortness of breath (1.4%), and fever (0.7%) were all uncommon among COVID-positive individuals It seems the more important point here is that the majority of the COVID-positive individuals were asymptomatic, putting another datapoint towards the conclusion that there are orders of magnitude more people that have this disease than have tested positive. We need more studies to gather data on these asym…

I'm never clear what asymptomatic means in this context.

Does it mean the period for which a patient is infectious before they become symptomatic?

Or do some people never become symptomatic?

And if it's the second, do they cease to be infectious like symptomatic individuals after a time? Or are they infectious long term (aka carriers)?

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#116

Post by jlmorton »

smsm42 wrote: post #101
jlmorton wrote: post #14

Earlier quoted context omitted.

We already have lots of data that says this is not true. For instance, on the Diamond Princess, widespread testing of a confined group initially found many asymptomatic infections, but the majority of those turned out to be pre-symptomatic, not asymptomatic. Longer term follow-up found ~25% of infections were asymptomatic. In the US, we're now doing significant amounts of testing, but we're still primarily testing on…

What's "significant amount of testing"? In Santa Clara country, for example, 16585 tests have been done[1], that's less than 1% of the population. I know from personal experience of several people that it's next to impossible to get tested if you don't have very severe symptoms. Positivity rate is 10.8% - over people which are sick enough to get tested. > Given a seeding of cases in mid-to-late January, even without…

> This sounds like circular logic - how we know it indeed started in January and not before?

Indeed, without serological testing, we're necessarily making some assumptions. But there's other evidence that points this way, too.

Genetic analysis based on samples from around China and the world point to a single index patient in Hubei Province around late November. China's case tracing has not gotten to an index patient, but it appears to be pretty close, and also points to an initial case around the same time.

If there was a single case in late November, then we'd expect a few hundred cases by January. Some number of these will have traveled, but many would not.

While the US clearly had major blind spots in testing, we were explicitly looking for symptomatic cases from China. The first detected case was Jan 21. There may have been a few earlier, but genetic analysis of cases in Washington point to an index patient in the Seattle area around that time.

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#117

Post by casefields »

Daishiman wrote: post #108
pm_me_ur_fullz wrote: post #9

Earlier quoted context omitted.

I really don't understand why people immediately want to discredit the idea that US patient zero was not the first in US. Or that this virus was around earlier and that there are limitations in contact tracing capabilities. This seems to have the toughest aspect of gaining consensus. Need antibody tests now, and ones that work reliably.

This hypothesis has already been tested by Stanford and found to be false.

New signs suggest coronavirus was in California far earlier than anyone knew: https://www.latimes.com/california/story/2020-04-11/bay-area...

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#118

Post by zzzzzzzza »

usaar333 wrote: post #112
zzzzzzzza wrote: post #107

Earlier quoted context omitted.

But you just ignored the evidence from the diamond princess? and meanwhile germany's data points toward a similar conclusion as the south korean data singapore also has a 1.5% deaths/recovered... and it's been higher in the past if you've been following closely (as high as 2%... question is where have all the new cases been coming from?) icelands data could easily be skewed if they avoided a nursing home getting infe…

An average age of 59 on the Diamond Princess (1.8% CFR) is not representative of the general population. This is a substantially more at-risk group. Germany and Singapore are also missing many infections. A recent serological study in Germany actually argued for 0.4%. You are correct that IFR is skewed by who the population is and what interventions are done. But then again, so is the often cited flu benchmark (where…

https://www.reddit.com/r/medicine/comments/fyf0yh/megathread... you mean this serological study?

And taiwan is at 1.5% CFR as well?

And still 60 or so unresolved diamond princess cases with ~7 in critical condition?

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#119

Post by wutbrodo »

sauwan wrote: post #48
jlmorton wrote: post #14

Earlier quoted context omitted.

We already have lots of data that says this is not true. For instance, on the Diamond Princess, widespread testing of a confined group initially found many asymptomatic infections, but the majority of those turned out to be pre-symptomatic, not asymptomatic. Longer term follow-up found ~25% of infections were asymptomatic. In the US, we're now doing significant amounts of testing, but we're still primarily testing on…

The Diamond Princess likely had a very atypical (older) population than the general population though. The CDC is currently estimating an R0 of 5.7, which has likely been repressed by shelter in place orders. But even if it was only 4 before any interventions, there's still a chance there there are closer to 20M cases in the US rather than the 660,000 now. My point is just that there's still a lot we don't know, and…

> The Diamond Princess likely had a very atypical (older) population than the general population though.

This would dovetail with the fact that places like sub-Saharan Africa and India haven't been hit very hard yet; they also happen to be _very_ young compared to Western countries.

Re: Covid-19 at a homeless shelter in Boston: Implications for universal testing

#120

Post by nkohari »

LatteLazy wrote: post #115
jcp2fa wrote: post #6

> Cough (7.5%), shortness of breath (1.4%), and fever (0.7%) were all uncommon among COVID-positive individuals It seems the more important point here is that the majority of the COVID-positive individuals were asymptomatic, putting another datapoint towards the conclusion that there are orders of magnitude more people that have this disease than have tested positive. We need more studies to gather data on these asym…

I'm never clear what asymptomatic means in this context. Does it mean the period for which a patient is infectious before they become symptomatic? Or do some people never become symptomatic? And if it's the second, do they cease to be infectious like symptomatic individuals after a time? Or are they infectious long term (aka carriers)?

Asymptomatic means the person had no symptoms at the time of the test, and possibly never developed symptoms. They could also have been presymptomatic, in which case they subsequently developed symptoms after the test. This study didn't do any follow-ups to differentiate.
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