Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free • Hacker News Board

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#231

Post by ineedasername » Fri, Apr 17, 2020, 2:30 AM UTC

capkutay wrote: post #164

eximius wrote: post #10

This is mixed news. While this indicates the death rate may be lower and the infection rate higher among the general population, the demographic of individuals in the US military are going to be of significantly higher health than the general population. So, it doesn't necessarily ease the risk for demographics already identified as 'at-risk'. If anything, their risk might be understated given the higher infection ra…

> the demographic of individuals in the US military are going to be of significantly higher health than the general population. 29 out of 33 pregnant women who tested positive at Columbia University Medical in NYC were also asymptomatic: https://www.medpagetoday.com/infectiousdisease/covid19/85965 With other viruses, pregnant women are typically considered at elevated risk. For example, they had a significantly highe…

Immune systems during pregnancy are vastly different than normal. It's quite possible that is a factor in the asymptomatic rate here. Many studies like this are using populations with inherent selection bias: that makes them interesting, for that population, but you cannot generalize from those results.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#232

Post by danieltillett » Fri, Apr 17, 2020, 2:31 AM UTC

mabbo wrote: post #147

azinman2 wrote: post #109

Earlier quoted context omitted.

Some percent of confirmed recovered cases never develop antibodies it seems.

Then how did they recover? If your body has no antibodies to the virus then why would the virus ever stop spreading within you?

This is an artefact of the current antibody tests, which mostly only sample a response to a single antigen. Which viral proteins you mount a response against will vary from individual to individual. To really know if you have no antibody response you need to test for a response to multiple antigens.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#233

Post by JshWright » Fri, Apr 17, 2020, 2:31 AM UTC

phkahler wrote: post #228

JshWright wrote: post #222

Earlier quoted context omitted.

How do you explain the hospitalization rate not climbing until a couple months later?

There are 2 strains?

That would be a very obvious thing to detect (and we have not seen evidence of that).

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#234

Post by jeremyjh » Fri, Apr 17, 2020, 2:36 AM UTC

Jordanpomeroy wrote: post #209

henrikschroder wrote: post #141

Earlier quoted context omitted.

No country except Iceland or South Korea knows how many are infected, everyone else's numbers are horribly wrong. But death numbers and hospitalization numbers don't lie. Sure, different countries are counting deaths differently, making it hard to compare them to each other, but the trajectories don't lie. And if you look at growth trajectories, no country is experiencing uncontrolled exponential growth at this point…

> But death numbers and hospitalization numbers don't lie. Well... there is some indication hospital staff are being directed to assume all cases are COVID19 until proven different. Patients that die with presumptive COVID19 are reported as COVID19 deaths. So agree, numbers don’t lie. But... handling emergencies effectively can lead to problematic numbers.

This is so tiresome. Someone has cancer for six months, gets COVID and dies 17 days later and now Tucker Carlson is here telling me not to count that death. How often do you really think it happens that someone is hospitalized with COVID (otherwise, they'd not even be getting tested most places in the world) and dies of something else a week later? I'm sure it has happened a few times, but what has also been happening hundreds of times every day is people die untested and are not included in the official numbers. Its ridiculous to even have this discussion, and the motivations for it are absolutely disgusting.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#235

Post by djrogers » Fri, Apr 17, 2020, 2:38 AM UTC

robbiep wrote: post #184

henrikschroder wrote: post #141

Earlier quoted context omitted.

No country except Iceland or South Korea knows how many are infected, everyone else's numbers are horribly wrong. But death numbers and hospitalization numbers don't lie. Sure, different countries are counting deaths differently, making it hard to compare them to each other, but the trajectories don't lie. And if you look at growth trajectories, no country is experiencing uncontrolled exponential growth at this point…

Austria did a relatively large scale antibody sample of its pop (0). Seems to discredit the notion that infections are vastly different than modelling. (0) https://amp.theguardian.com/world/2020/apr/10/less-than-1-of...

FTA:

The study, conducted from 1-6 April, tested 1,554 people. It did not involve antibody tests, which can tell whether a person was previously infected and is therefore probably immune. Future studies should involve antibody tests, the government has said, to inform policy as the country starts to reopen shops from 14 April.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#236

Post by danieltillett » Fri, Apr 17, 2020, 2:38 AM UTC

ImaCake wrote: post #105

andrewla wrote: post #13

There's always the chance that the test itself is not particularly good and just has a high false positive rate. Although it is difficult for a PCR test to produce a match if there is no genetic material present, it may amplify trace signals, depending on the cutoffs chosen.

I looked into this a few weeks ago. The PCR test has an incredibly low false positive rate, below 1%. It is low enough that it is feasible to test a 100,000 people and expect basically zero false positives. The false negative rate is somewhere around 30%. So the real danger with PCR is that you will miss cases. The opposite is true for the antibody tests. The false negative rate is around 10% and the false positive r…

If not done well PCR has an incredibly high false positive rate. If you contaminate your set up area (or equipment) with past PCR amplification material you will get a very high rate of PCR positivity.

Of course if you do things correctly this shouldn’t happen, but if the average pathology lab technician is as skilled as my ex-students and colleagues (and myself) then I would be not be so keen to rule out false positives.

Yes there is a major issue with false negatives, especially when the swab was not performed or stored correctly. RNA is not very stable and it is very easy to destroy all the viral RNA if you are not careful.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#237

Post by losvedir » Fri, Apr 17, 2020, 2:39 AM UTC

Mikeb85 wrote: post #35

All the data points to the fact that coronavirus is more widespread and less deadly than most outlets are reporting (after all, increase the denominator, the % goes down). The countries with the lowest death rates are also the countries that did the most comprehensive testing. Ditto for this aircraft carrier. Of course governments and outlets are fearmongering lest they be accused of not doing enough, but this thing…

Follow the Iceland data. They've tested about 10% of their population, including random testing of seemingly healthy people. They've almost eliminated new cases. Death follows about three weeks after symptoms, so we'll know the infection fatality rate soon. Right now it's quite low there, but I predict it will trend towards 1% - 1.5% like we saw in Germany and South Korea, whose rates also started out low. That's >10x the death rate of the flu and would indicate half a million to a million dead in the US.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#238

Post by aazaa » Fri, Apr 17, 2020, 2:39 AM UTC

Nowhere does the article mention which kind of test was run. Was it qPCR or serological?

The latter tests whether you have had an infection. The former tests whether you currently have one.

The distinction between presymptomatic and asymptomatic is tricky as well, but is less of an issue with a serological test than a qPCR.

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#239

Post by serf » Fri, Apr 17, 2020, 2:42 AM UTC

JshWright wrote: post #233

phkahler wrote: post #228

Earlier quoted context omitted.

There are 2 strains?

That would be a very obvious thing to detect (and we have not seen evidence of that).

evidence of what? two separate strains?

this paper mentions two strains[0], 'L' and 'S' type, was it refuted?

[0]: https://academic.oup.com/nsr/article/doi/10.1093/nsr/nwaa036...

Re: Coronavirus clue? Most cases aboard U.S. aircraft carrier are symptom-free

#240

Post by danieltillett » Fri, Apr 17, 2020, 2:43 AM UTC

scythe wrote: post #20

Do we know if these cases are truly asymptomatic or just presymptomatic as was observed on the Diamond Princess? 48% asymptomatic initially: https://www.niid.go.jp/niid/en/2019-ncov-e/9407-covid-dp-fe-... 18% asymptomatic retrospectively: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078829/ Also, 58% of asymptomatic COVID-19 infections still show damage to the lungs on CT: https://appliedradiology.com/articles/study…

Do you know any studies of the outcome of the 32 Diamond Princess patients that were the ICU at the time the boat was emptied? I have been looking and I can’t find any data on what was the final clinical outcome of all patients on the Diamond Princess?