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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

#41

Post by ben_w »

bgorman wrote: post #29
smallgovt wrote: post #17

Earlier quoted context omitted.

> We need more studies to gather data on these asymptomatic cases if we want to reopen the economy soon. I don't understand what's so hard about measuring population infection rate. Assuming the population infection rate is between 1-10%, we would only need to do around ~500 randomized tests to achieve a 95% confidence interval of +/- 1%. For example, let's say we tested 500 random NYC residents for COVID and found t…

The thing you are missing is world governments want to milk this crisis, not act objectively. There is simply no other explanation.

Another explanation is that the exact infection level isn’t important when the observed all-causes fatality rate is double [0] its seasonal average and everyone is therefore busy firefighting the immediate and obvious problems.

[0] varies by region, but see for example this graph of London: https://pbs.twimg.com/media/EVlO-28XQAA30xu?format=jpg&name=...

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

#43

Post by duxup »

DenisM wrote: post #28
smallgovt wrote: post #17

Earlier quoted context omitted.

> We need more studies to gather data on these asymptomatic cases if we want to reopen the economy soon. I don't understand what's so hard about measuring population infection rate. Assuming the population infection rate is between 1-10%, we would only need to do around ~500 randomized tests to achieve a 95% confidence interval of +/- 1%. For example, let's say we tested 500 random NYC residents for COVID and found t…

False positive rate of some antibody tests is 9%, which makes any effect size below that invisible.

Jebus, 9% false positive ... is that even useful?

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

#44

Post by danielharan »

rb808 wrote: post #4

Also 15% of pregnant Moms in NYC had the virus. This could already be much more widely spread that people think. https://www.nbcnewyork.com/news/local/nyc-hospital-finds-hig...

Many of those people testing positive were presymptomatic (some even developed symptoms during the follow-up period). It typically takes several days to develop symptoms.

Also worth considering is the period mentioned in the correspondence is one in which there was very fast exponential growth. When more of the positive cases are recent, it's only normal that they don't show symptoms yet.

Besides the test used showing a lot of false positives, the population of pregnant women looked at had a much higher rate of symptomatic infections 1 month ago than the entire population does today... we should be very cautious about concluding much from that sample.

https://www.nejm.org/doi/full/10.1056/NEJMc2009316

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

#45

Post by stefco_ »

smallgovt wrote: post #17
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…

> We need more studies to gather data on these asymptomatic cases if we want to reopen the economy soon. I don't understand what's so hard about measuring population infection rate. Assuming the population infection rate is between 1-10%, we would only need to do around ~500 randomized tests to achieve a 95% confidence interval of +/- 1%. For example, let's say we tested 500 random NYC residents for COVID and found t…

There's good reason to suspect strong regional variation, which means that finding a representative sample of 500 is hard. But that would still be technically possible (look at South Korea and China); we clearly lack to political will to do proper testing in USA.

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

#46

Post by _bxg1 »

kens wrote: post #34

Regarding the title "Covid+", it seems that most people (even on the news) don't care about the difference between SARS-CoV-2 (the virus) and COVID-19 (the disease). Is this distinction being abandoned? (I'm not trying to be pedantic here; I'm just curious about the common usage.)

For the practical purposes of decision-making by regular people, the distinction probably doesn't matter and would be confusing

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

#47

Post by gowld »

raphlinus wrote: post #18
gnulinux wrote: post #8

Earlier quoted context omitted.

It seems to indicate this disease infected a lot more than what we see, and maybe mortality rate is lower than what we currently assume. Maybe it's around 0.1% to 0.5%. So is it possible this disease appeared in China way before December, maybe a few months back. Then in December it reached a saturation point (i.e. infected hundreds of thousands of people, so deaths started to get noticed by respiratory specialists).…

No. We know from genomic analysis [1] that "The common ancestor of circulating viruses appears to have emerged in Wuhan, China, in late Nov or early Dec 2019." It's fun to speculate about other possibilities, but I personally like to stick to what the science tells us. [1]: https://twitter.com/nextstrain/status/1248707010750640128

That report appears to based on genomic analysis, which obviously only includes cases that were tested, not undocumented transmissions before the discovery.

The article you cite says: "The common ancestor of circulating viruses appears to have emerged in Wuhan, China, in late Nov or early Dec 2019. Accordingly, the majority of sampled and inferred ancestral cases were located in Asia during this early period. "

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

#48

Post by sauwan »

jlmorton wrote: post #14
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…

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 small changes in our understanding could implicate massive changes in the reality on the ground.

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

#49

Post by smallgovt »

credit_guy wrote: post #21
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…

My bet is that it's much more than 10%. In NYC I think it's at least 20%-30% by now. Obviously, I don't have any more data than what you can find online, but anecdotally, I think one of my sons had it; he most likely got it from his piano teacher who exhibited all the Covid symptoms (fever, dry cough, loss of smell), but was never tested. I think at least myself and my wife got this from him as well; likely his two s…

Does this study change your mind on that 20-30% figure? After all, the study measured a 35% infection rate for people living in close quarters with other infected individuals. Surely, the overall population would yield a much lower infection rate than this?

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

#50

Post by [deleted] »

smallgovt wrote: post #17
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…

> We need more studies to gather data on these asymptomatic cases if we want to reopen the economy soon. I don't understand what's so hard about measuring population infection rate. Assuming the population infection rate is between 1-10%, we would only need to do around ~500 randomized tests to achieve a 95% confidence interval of +/- 1%. For example, let's say we tested 500 random NYC residents for COVID and found t…

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