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Comment by danieltillett | Hacker News Reader

A prison is very much like a cruise ship from a viral perspective. We know from the cruise ship data like the Diamond Princess that most people had no symptoms initially, but overtime most people became symptomatic [1].

Of course if we are really lucky and the prison was infected with a naturally attenuated strain we should make use of it [2].

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078829/

2. https://www.tillett.info/2020/04/12/how-would-a-search-for-a...

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> We know from the cruise ship data like the Diamond Princess that most people had no symptoms initially, but overtime most people became symptomatic [1].

Your wording is too strong. Data is 50% asymptomatic at time of testing, paper models that that number dropped to 20%.

> from paper on 19 February and 50.5% (320/634) on 20 February (Table). Soon after identification of the first infections, both symptomatic and asymptomatic cases were transported to designated medical facilities specialised in infectious diseases in Japan. However, these patients were treated as external (imported) cases, and a detailed description of their clinical progression is not publicly available.

We conducted statistical modelling to derive the delay-adjusted asymptomatic proportion of infections, along with the infections’ timeline. The estimated asymptomatic proportion was 17.9% (95% credible interval (CrI): 15.5–20.2%).

If you read in the discussion they reference other data sets to show that more asymptomatic become symptomatic. It is also what the Icelanders found with their data too where most people started out asymptomatic, but many later developed symptoms.

In a region in Italy they tested [1] people twice, 2 weeks apart, and found that 43% were completely asymptomatic over the course of the infection.

[1] https://www.medrxiv.org/content/10.1101/2020.04.17.20053157v...

About 50% of the population in that study is over 50. I think it's a bad idea to draw generic conclusions about the disease from a diverse age range. You end up with conclusions that aren't relevant to either. Glossing over the tables I don't see any data about symptomatic over the two weeks by age. I'd be shocked if the rates of becoming symptomatic are not much higher for the elderly and much lower for the young. Didn't read it in depth though.

See: Simpson’s paradox, where trends in subgroups, taken together, can indicate a different trend.

https://en.wikipedia.org/wiki/Simpson%27s_paradox

Trends in subgroups can indicate a different trend. The above comment is not about a linear trend. It's about an average statistic for a population based on a sample that's not representative of the population age distribution for a process that probably isn't linear across ages. If the older half becomes symptomatic 100% of the time, and the younger half becomes symptomatic 0% of the time, it's very misleading, though not technically incorrect to say people become symptomatic 50% of the time. There's a huge impact on how to handle the problem.

Doesn’t that mean that 57% were symptomatic?

I didn't intend to contradict you. Granted it's totally valid to assume that many people who are tested positive and show no symptoms might develop some later, but I just thought it might be of interest to some people to have numbers where they tested patients twice over a long enough interval to conclude that they really were asymptomatic.

I think that. depending on the air conditioning system, it might be quite a bit worse. The density of people is huge, air flows freely between cells, prisoners eat packed together at communal tables. I bet R is like 10-20.

On the Diamond Princess it was about around 14. I would expect prisons to be much the same.

Do you know how that broke down by room? Is there data on that? I wanted to make a map by room of infections, because that data point should be useful, e.g. was the rate higher or lower in rooms with outside access? Crew versus passengers? I just don't know of it already exists, or how to source the data.

We seemed to have early fluffed the data out of the Diamond Princess. We aren’t even tracking how many people died - it seems once everyone got off the ship all interest in it was lost.

I'd have thought that more airflow would help to reduce transmission, given that like other coronaviruses it's transmitted by droplets and not aerosol. Droplets would have trouble staying suspended with more air movement, and would be unlikely to make it through centralised air conditioning systems without becoming deposited on some surface within them.

The eating together at communal tables, and any other close-quarters communal activities, seem far more relevant to increased R than the air conditioning system and the free airflow.

Not really, not in a prison: Droplets exist in a continuum, and while most are large enough to drop out of the air, as they get smaller they stay in the air longer, and require less air current to stay aloft. [0]

As such, while the small particles may not exists in sufficient quantities when it is just one infected, or a few infected inmates, but with each infected inmate the concentrations of those small particles will increase. Let's say they're normally 0.5% of the total particle exhalations: 10 inmates get sick through direct contact, and their combined exhalations bring the quantity of smaller, longer lived particles up to an equivalent of 5%. More get sick through contact, bringing it to 20%. At some point, you hit a critical mass where there is a sufficient concentration to infect people, and creates a downward spiral from there.

[0] https://www.nytimes.com/2020/04/14/health/coronavirus-six-fe...

> A prison is very much like a cruise ship from a viral perspective.

Prisons are much worse. Chow line with men almost heel to toe. Commissary line. Med line. Recycled air. Big crowds in small spaces.

    > Prisons are much worse. Chow line with men almost
    > heel to toe. Commissary line. Med line. Recycled
    > air. Big crowds in small spaces.

How could the prison be much worse than the cruise ship you just described?

OP is describing a prison.

That's the joke.

Stress.

But in prisons you spend way more time isolated. There is less freedom of travel, and I'd assume they'd be less physical contact (although maybe more if you considered shared showers).

They share cells. They move around at set times. They are not isolated.

The soap is expensive, they don't have it and masks are not allowed.

I am communicating daily with a prison inmate and they are required to wear masks all the time. But yes, that won't help due to all the other aspects of prison.

That’s a cruise

I don't see them advertising it like that.

The table settings might be nicer, but it's still a chowline of people asses-to-elbows.

https://c8.alamy.com/comp/B5D6CE/breakfast-buffet-served-onb...

I guess you guys will have to wait for your first time in jail to spot the differences, if you aren't going to learn from strangers on the Internet

We could make the same dumb jokes about:

Popular restaurants, clubs, sporting events, concerts, movie theaters, stores on Black Friday, etc etc etc.

(Personally, I’ve been on 5 different cruises and they’ve each been among the best vacations of my life. But lol lots of people so they must be just like prisons amirite?)

I don’t live at/in a restaurant, club, sporting event, concert, movie, or store for a week or more.

Perhaps you do. But if you don’t, none of those things are similar to a week-long cruise at all, since you are there for hours and not days.

> I don’t live at/in a restaurant, club, sporting event, concert, movie, or store for a week or more.

I don't live asses-to-elbows in line with people for a full week on a cruise ship either. I have a room to myself. What point are you trying to make, exactly?

The room is only for sleeping. Everything else is massive crowded common spaces

Apart from the demographics, they seem to me pretty similar ;)

Prison demographics are very different than cruise ships, so might be interesting if different

To give evidence to this comment, the gp's source notes that ~75% of those that tested positive for covid were >60 years old. Whereas the BOP [0] reports a distinctly different age demographic. We know that covid dramatically affects people differently based on age, so I wouldn't suspect IFR to be similar to that of a cruise ship (where it is typical for the demographic to be older and retired)

[0] https://www.bop.gov/about/statistics/statistics_inmate_age.j...

Since the hospitalization and mortality rates vary so much with age, it would be surprising if the rate of asymptomatic cases didn't. Since prisons skew young we would expect a much higher proportion of asymptomatics to be found there than in the general population.

If you are going to say they skew young (or make any claim), please provide some figures. I did a search, from https://www.bop.gov/about/statistics/statistics_inmate_age.j...

  <18    Under 18     6         0.0%
  18    Ages 18-21    1,866     1.1%
  22    Ages 22-25    8,366     4.9%
  26    Ages 26-30    21,931    12.8%
  31    Ages 31-35    28,182    16.4%
  36    Ages 36-40    31,206    18.2%
  41    Ages 41-45    26,545    15.5%
  46    Ages 46-50    19,979    11.6%
  51    Ages 51-55    13,749    8.0%
  56    Ages 56-60    9,475     5.5%
  61    Ages 61-65    5,467     3.2%
  >65   Over 65       4,746     2.8%

Whether this backs you up or not depends on what 'young' is.

Skew isn't the right word. But relative to average this is definitely younger.

https://www.indexmundi.com/united_states/age_structure.html

Local demographics will vary wildly but it looks like the baseline would be 16% 65 and older, 13% in the range of 55-64. Since we're talking about prisons we should probably ignore the population under 18, so the normalized expected population over 65 is closer to 20%.

That's federal prison data. People who go to federal prison aren't necessarily the same cross-section of the population who go to state prison.

Anyway, those numbers are certainly much younger than the median age in the USA nationally, which is 39 years with over 65s being 15% of the population.

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