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Comment by ekianjo | Hacker News Reader

> lockdown does not always result in a low enough rate of transmission to avoid a crisis.

On that topic, Cuomo just declared that among the last batch of infected people in NY, more than 80% were apparently respecting the lockdown and staying at home and we have no idea how they were even contaminated. Puzzling.

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That's a bit of a stretch of what he said (https://www.cnbc.com/2020/05/06/ny-gov-cuomo-says-its-shocki...).

* Hospitalizations, not cases and not infections. That skews old/out of the workforce.

* The stat is that 66% live at home and 84% not working.

* That doesn't mean they are 100% to the letter respecting social distancing. Nor does it mean they don't have housemates that aren't working. (That could be the case, but there's no data).

Generally lockdown in the US has been pretty loose. Many people have left their homes, and had the opportunity to be exposed.

I also think there is a likelihood that between presymptomatic/asymptomatic transmission, and the possibility of 2 week incubation this seems like a nightmare to track transmission.

A friend who had SARS-cov2 was sick for 30+ days. So it’s not clear to me that a mild infection would be over in 14 days.

> Generally lockdown in the US has been pretty loose.

I'd like to see the same study done outside of NY, because the NY lockdown was one of the most stringent in the country, from what I've read.

Was it? It reads about the same as the Bay Area's, possibly even a bit looser.

If it's a mild infection, by definition, the immune system has squashed it. If it didn't, the virus would take hold; it's not a latent viral infection like herpes.

Edit: okay, okay, I didn't specify "a mild infection that stays mild and goes away". We know complications can arise and the infection can progress into severe symptoms. Plenty of examples.

The evidence does not support this viewpoint. Also, things are complicated by the evidence that the worst symptoms are caused by cytokine storm, i.e. an auto-immune response.

Which evidence? Are you referring to the "lag" in immune response in the initial stage of infection?

Perhaps I should have said there is no evidence that I am aware of that supports that viewpoint. Instead, there is evidence that asymptomatic people can transmit the virus. No symptoms does not mean no virus.

Asymptomatic does not mean permanently infected

There are plenty of cases that start with mild symptoms, and then progress to severe/critical after about a week. Boris Johnson is a perfect example of this.

Please don't spread misinformation.

I've had coughs that have lasted a month or more - including at the start of lockdown [#] (caught from my son, I think, who was coughing for 8 weeks or more). I've always assumed that this is because a virus can be kept at low levels, but can "hide" in the body not coming across antibodies that will harm it, but not spreading enough to create a heightened immune response??

Kinda like when you don't take a full course of antibiotics, the latent infection grows again to problem levels.

You indicate this is wrong thinking (not a suprise as it's just a null hypothesis from someone without biology training): so what is going on when you have a cough/blocked nose for weeks on end?

{# I'm very curious to find if the virus I had was Covid19; it sent me to bed with mild flu-like symptoms, gave a tight chest, had me occasionally [not persistently] coughing for weeks. No noticeable anosmia. Very little phlegm; no snot (nasal/sinus mucus).}

More importantly than the tightness or looseness, we don't really have any facilities set up for if one member of a household gets sick and wants to stay away from the other members and not infect them. I can understand discharging patients back to their families before they're PCR negative because infectiousness in SARS-CoV-2 seems to be very frontloaded. But for people recently diagnosed with mild cases of Covid-19 it would be good if we had places for them to quarantine outside their households even if it was on a voluntary basis.

Reference: "Preliminary data submitted by 113 hospitals over the last three days show most new admissions have mostly been staying home; they're predominantly from the downstate area (57 percent NYC, 18 percent Long Island) and people of color. Most of them are older and non-essential employees; 66 percent were admitted from their own residences.

Of the new New York City hospitalizations, 90 percent have not been traveling by car service, personal automobile, mass transit or even walking around. If they've been working, they've been doing it from home and apparently weren't going out much, the governor said."

https://www.nbcnewyork.com/news/coronavirus/subway-shutdown-...

I wonder about other people in their households, who may be going outside more or even working.

In Wuhan the infection rate went down only when they started to place any person who required quarantine to separated buildings.

This points out that perhaps transmission across apartment building is significant.

That data is poorly framed. I have no idea why he's surprised. This is the one I've seen people cite:

https://i.imgur.com/b9RAr8g.jpg

Cuomo:

> 66% of the people were at home, which is shocking to us...This is a surprise: Overwhelmingly, the people were at home...We thought maybe they were taking public transportation, and we’ve taken special precautions on public transportation, but actually no, because these people were literally at home.

That chart is titled "Source of Admission," not "Was supposed to be staying home." Someone providing critical services who woke up with a fever and got tested would fall under "home."

There's also nothing to compare it to. What percent of people are in those circumstances?

To what I think he misread and was surprised by, the idea that most people getting hospitalized were sheltering in-place (a stat I haven't seen), with how many New Yorkers who have been exposed to SARS-CoV2, you'd expect essential workers who are going out every day to be more likely to be immune at this point, those sheltering in place aren't. More people are sheltering in-place than out working, they're less likely to have been exposed, so I wouldn't be surprised to see more of them infected. But again, that's not the data Cuomo was talking about with "66%."

That makes sense to me. The lockdown has reduced people getting infected from being out. There are still people getting infected and that is people in institutions (care homes, prisons, hospitals) and people in houses. Ie if one person in a house of 4 gets the virus and passes it on to the rest of the family 75% of people infected were staying at home.

News alert: Americans lie and/or are misinformed on surveys.

There's a strong incentive, if you're going in to hospital with Covid19, to lie. They ask "were you sheltering in place?" and you'd think "if I answer no, will I be denied care?". That's going to make survey almost useless, a secondary survey (eg speak to neighbors) might be better but would still be relatively poor.

That's not what the numbers meant. The majority were admitted from home to the hospital, i.e., they were not institutionalized or homeless.

Do you have a link? With incubation periods of up to two weeks and cases without symptoms everything is possible.

I've worried about apartments for that reason. If air circulation is shared, wouldn't it be possible to transmit from apartment to apartment?

I think it would be worth a test, at least.

No, the virus doesn't just float around in the air, at least, not for any appreciable amount of time. It's much more likely that people in these apartments are touching the same elevator buttons and then wiping their eyes and contracting the virus.

> No, the virus doesn't just float around in the air, at least, not for any appreciable amount of time.

Here is a pretty approachable summary of how transmission happens that contains a review of some specific cases where airflow was critical to transmitting the infection: https://erinbromage.wixsite.com/covid19/post/the-risks-know-.... None of these occurred in isolated spaces connected by shared ventilation but I would be cautious about saying flatly that it can't happen.

I didn't say flatly that it can't happen. I said it can't happen at any appreciable distance. Obviously, if someone sneezes in your mouth your going to get sick.

That's not what you said, and why don't you take a look at that article I linked. The restaurant case and the call center case it looks at were hardly in the category of "someone sneezes in your mouth."

> No, the virus doesn't just float around in the air

I'd be interested in any references you can point to that explain why that doesn't happen. A priori I would expect virus particles to be able to remain airborne indefinitely. Viruses are very small, much smaller than pollen grains that I believe are well known to remain airborne over long distances so I would think Brownian motion from collisions with air molecules would suffice to keep them aloft.

There are multiple lines of evidence that suggest airborne transmission is the primary form of transmission. For example: https://twitter.com/JeremyKonyndyk/status/125372588101882675...

"Lines of evidence" and "twitter.com" do not belong in the same sentence. If there's something of substance in a tweet, link the substance.

If this were an academic journal, I would. But this is a casual web forum.

The setup of this whole thread is 'trustable data and scientific method'.

Also, please be aware that a name is often not enough to show that a source is relatively trustworthy, some credentials can help; this is a worldwide forum.

Surely that depends on whose tweets they are? If its Jeremy Konyndyk or Scott Gottlieb or such that's a pretty decent source. If it's a celebrity or political figure or some random person less so.

It's precisely because of the way infections cluster in cases like that that we can tell that we're not seeing (much at least) long range airborne transmission. It this was a true aerosol like you see with chickenpox, measles, or TB you wouldn't be seeing such a nice separation as that. It looks like the furthest away you should be able to be infected someone is maybe 20 or 30 feet if you sneeze without covering your nose. That's the significance of Mr. Konyndyk talking about droplets rather than aerosols. Though it was a big deal in the original SARS outbreak that you could generate aerosols via intubation which caused some nurses wearing surgical masks to get sick in that outbreak.

Unfortunately, even talking and breathing generates micro-droplets that remain airborne for hours: https://www.youtube.com/watch?v=H2azcn7MqOU

> No, the virus doesn't just float around in the air, at least, not for any appreciable amount of time.

Can you share what degree of certainty you ascribe to that claim?

Edit: Also, does this change it? https://erinbromage.wixsite.com/covid19/post/the-risks-know-...

That agrees that the virus is mostly transmitted via droplets rather aerosolized virus particles. A bare virus can float in the air for quite a while but all the evidence we have, especially stuff like form that site, seems to show that that isn't a route by which people are being infected. Instead its being transmitted over shorter distances, generally around 6 feet but longer if someone is shouting, singing, coughing without covering, or just directly downwind.

??? It talks about miniscule droplets that could stay in the air for minutes, and move downwind quite easily.

I think what the parent commenter is saying is that maybe the virus stays in the air like that but it's not a way in which people get infected, otherwise the clusters wouldn't be so tight. Any tracing would be impossible for example. One possibility is that you need a threshold amount of virus to infect you so close contact is necessary.

There was a SARS outbreak in an apartment building due to shared (and presumably faulty) plumbing, and CV-19 does seem to have a fecal route.

That plumbing was not in any way up to standard. If you've got s-curves in your pipes you shouldn't have anything to worry about with getting this (or cholora, or norovirus) via your toilet from another unit.

I don't think we've actually had any fecal transmission with SARS-2 either, or even had someone successfully culture live virus from a stool sample. We've seen a lot of virus RNA show up in stool from infected patients but that might be due to swallowed saliva. I'd try to avoid contact with other people's feces in any event but the danger here really does seem to be mostly droplets.

Ventilation systems like what happened in South Korea?

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