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Comment by voidmain | Hacker News Reader

We know that sufficiently strong social distancing - and universal mask use - can reduce Re below 1, causing the epidemic to shrink exponentially instead of growing exponentially. Once it is small enough, good testing and contact tracing should be able to contribute a significant reduction to Re, so that you can back off on more costly measures.

As hard as it sounds for the economy to adapt to extreme social distancing for a short time and moderate for a long time, it seems like a better bet to me than trying to increase intensive care capacity - which already consumes a nontrivial fraction of gdp - by orders of magnitude and write off millions of lives.

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> As hard as it sounds for the economy to adapt to extreme social distancing for a short time and moderate for a long time, it seems like a better bet to me than trying to increase intensive care capacity

The article is saying do both which makes sense. In the case of CV19, we don't need to build new state-of-the-art ICUs. We only need to prepare a temporary overflow capacity that can handle a relatively brief surge of a very particular (and largely similar) kind of patient which is a still-challenging but much more tractable problem.

Space - Large circus tent-like temporary buildings used for conventions can be erected in hospital parking lots in a day.

Beds - While $5,000 robo-beds are wonderful, CV19 patients needing hospitalization have pneumonia symptoms and need to be at a constant ~30% incline - so La-Z-Boy lounge chairs are actually a decent option.

Mechanical Ventilators - The U.S. has about 160,000 ventilators. The key here is to get them where they need to be when they are needed. The chances that CV19 surges will happen everywhere at once in an area as large as CONUS are essentially zero. In Italy, while Lombardy in the North was running out of ventilators, there were hospitals in the south with unused devices. 98k of our national 160k vents are mothballed older versions in storage. Preparing some portion of these for rapid deployment, such as positioning them in FedEx / UPS overnight hubs in the central U.S. can have them ready to be wherever a surge begins to build in less than 18 hours.

Ventilator Operators - Becoming certified to operate a ventilator usually requires six months and the next gap will be having enough qualified operators where and when they're needed. An experiment was already conducted where various medically-trained, but not vent-trained, people from RNs to pediatricians to veterinarians were run through 2 days of intensive vent training and tested for apprentice-level proficiency. The winners were the veterinarians, outperforming the other specialties in performance (go figure). The resulting model showed one certified vent op can supervise six apprentice-level ops who each handle X beds (I forget the exact numbers). But you get the idea and fortunately, we have a lot of vets in the U.S.

We still have some low-digit number of weeks before likely patient surges start cropping up in different areas. Neither spread-reduction nor surge capacity increases will work perfectly, but by pragmatically working both issues together it's likely we can avert many preventable deaths.

thanks for your insights,

> The winners were the veterinarians, outperforming the other specialties in performance (go figure).

1) Veterinarians deal with animals, which aren't as domesticated, civilized, intellectual, ... in some sense. So as opposed to humans they will not understand the reason why they are undergoing treatment, nor have blind faith in this human they don't know. So when an animal experiences higher or lower levels of comfort it will be more "honest" in it's body language in response to the way it is handled, or what it is feeling physically during treatment. Also the veterinarian doesn't need to model abstract conscious thought of the subject, while with humans this is inevitable and can be distracting. Could this explain the higher performance of veterinarians? After treating cows, horses, dogs, cats, ... they view the human in a way as just another animal, and pay more attention to the intuitive body language than to abstract social cues?

>CV19 patients needing hospitalization have pneumonia symptoms and need to be at a constant ~30% incline

this is with heads up, or feet up?

I read a (news, not journal) article with pictures of the Italian patients on their belly, because it allows the mucous to flow from the finely branched areas to flow into the more accessible pathways, so the mucous would collect there where it was easier to remove.

2) IF hospitals get overrun locally, and people are left to their own devices, would it be possible to disinfect a plastic tube, attach a digital endoscopic camera, disinfect both, and introduce it oneself to suck out any accumulating puddles? what would be the maximum tolerable cross section to get it to the point of collecting the mucous?

3) instead of ventilation which is very hard to DIY because of volutrauma and barotrauma, could circulating air work? I envision a double tube brought deep into the common pathway (without obstructing passage of air for breathing, or alternatively a third tube to atmosphere), and simply introducing the same volume as air as being removed by the other tube, so a significant fraction of air will directly exit again through the second tube, but some of the air will mix with the local ambient air in the lungs before exiting through the second tube. i.e. the setup does not replace nor displace breathing, but simply circulates air. This might inadvertently cool the lungs, so there should be proper temperature control on the high flow rate air.

A thousand times this!

The viral growth is not the only exponential thing here, the costs of bringing down R0 are also highly non-linear, and it works both for and against us.

Against: it is going to be much more expensive to get R0 from 1.5 to 1 than from 4 to 3.5. A plausible assumption may be that a constant percentage reduction carries a fixed cost. Also: the more infected you have the more expensive it becomes.

For: As you said, once it's brought under control, cheaper measures that don't work at scale can be be used it to keep it from flaring up again [1]. That's what China is trying to do and so far it seems to work well. The whole herd immunity insanity seems to be predicated on the idea that social distancing does not work and the second wave will kill you later. But evidence so far suggests the opposite, although this may change.

In terms of war-style production: It seems criminally stupid that so far no Western country has embraced readily available trivial and ridiculously low cost means to significantly reduce spread. Like getting everyone to wear face masks, all the time. There seems to be excellent evidence it is very effective for bringing R0 down massively, both from academic studies on influenza[2] and SARS and also from circumstantial evidence like just comparing case growth between face mask using countries and non-using countries for the current outbreak[3]. Of course that requires actually producing a lot of face masks – but how hard can that be? As far as I am aware the current state is that even terrible face masks would help massively with preventing carriers from infecting others.

[1] This argument is also made here:

https://arguablywrong.home.blog/2020/03/12/epidemiological-m...

The cost per live is somewhere on the humanitarian end of the spectrum, but I think this argument is worth engaging with. If there is any realistic chance of eradicating covid-19 rather than just mitigating it, clearly is is what we must do and will pay enormous dividends even in the fairly short term.

[2] e.g. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1539-6924....

[3] https://twitter.com/epsilon3141/status/1238838106440241152

> - and universal mask use -

It's really unfortunate that the general population of the US has zero cultural familiarity with using masks to prevent the spread of disease. This really seems like the time to do everything possible in that regard, but we don't have the supplies.

In normal times, surgical masks are cheap. If we had the supply, we should be handing them out by the dozen to households in infected areas, at airports, etc.

This touches on another hobby horse of mine. Our society, both legally and as a matter of cultural habit, tends to prefer inaction to imperfect action. The fallacy, a sort of dual to the better known "We must do something, this is something, therefore we must do this", seems to be

1. Perfection is better than imperfection

2. All our options are imperfect

3. Therefore, we will do nothing

I am almost sure that our society, even without prior preparation, could physically produce huge numbers of "more effective than nothing" masks (especially for protecting others from the wearer, which is easier) very quickly at, say, 10x the cost (because you are recruiting less than ideal resources, like factory lines designed for other things that need extra labor) and 75% effectiveness (because you aren't applying the usual extremely strict standards that apply to NIOSH masks or whatever). Even if everyone taped a paper towel or sock over their face I bet it would reduce large droplet transmission by 50%. But we are not able to do so, because

1. These masks would cost more than masks used to cost ("price gouging!"). Imperfect.

2. They wouldn't work as perfectly as physically possible. Imperfect.

3. Some people would make money selling fake masks or whatever in the confusion. Imperfect.

4. We already made a bunch of regulations mandating perfection and no one wants to take responsibility for removing them

and maybe also

5. The people who should have stockpiled masks (edit: in the government or medical supply chain, I'm not saying individuals should have thought of this!) would have to admit their mistakes

So, "we" lie to people that masks are useless (charitably, so doctors can have more; uncharitably, because 5) and do nothing.

Yes, why isn't there more focus on getting R0 < 1? Flattening the curve seems like a good idea, but R0 < 1 also seems very important.

(I've been trying to simulate this, but ended up battling matplotlib unsuccessfully to create a graph.)

I think the focus is the same. Flattening the curve effectively means reducing the R0, and the steps being taken now could theoretically get it below 1.

South Korea seems to have done this; they have more testing than anywhere else, yet they have less new cases now than they did last week.

“Flatten the curve” is to increase compliance by making accomplishing something seem more realistic, even at an individual level.

So what are you going to do when the virus is gone in your city/state/country, isolate yourself from the rest of the world? Because the timeline/situation will be different for many other places.

That is exactly what is happening in Malaysia and Taiwan right now. Both countries have it under control up until a couple days ago but every other country around the world is not doing well and new outbreaks are happening (returning travelers, religious gatherings). Malaysia just announced total ban of incoming and outgoing traveling for the next 2 weeks.

Return to travel restrictions + contact tracing, and if community spread flares up again, reinstitute social distancing. Repeat until vaccine is developed.

I'm not sure why you're downvoted. That is exactly the right approach. Implement serious social distancing measures to reduce R0 below 1, get local outbreak under control, and then work on keeping it contained, increasing measures when necessary. Once it's more established which countries are effectively controlling the virus, travel could be more open with those countries, and more restricted with those that still have active outbreaks. (Which doesn't necessarily mean cutting off completely, but perhaps only essential travel and cargo, or unrestricted but 14 day isolation on arrival.)

Interestingly, that comment started out as +3 and is down to -2 now.

I think it may be a good harbinger of the public's willingness to endure repeated, long-term changes to their behavior. The way I see this going, we're going to get lockdowns in most countries within the next week or so. After 6 weeks or so, new cases will be negligible, and we'll declare victory and pick up our lives. The virus will silently spread from a few undetected cases during the summer, but then take off again around October, when we get a second wave. Assuming it hasn't mutated to become significantly less deadly (pretty likely - see sibling threads), that will be the real killer, because instead of starting from 1 index case in 1 city it'll be seeded from tens of thousands of sleeper cases across the globe. Public opinion won't support a second lockdown then - people will just be left to die with their families.

I would like to think that we would keep expanding testing infrastructure during the reprieve, and so wouldn't be caught off guard. For the most part the people running large scale public health policy are smart and well informed, so this risk won't be unknown.

> Interestingly, that comment started out as +3 and is down to -2 now.

Is there somewhere to check that score, or is it a higher karma feature?

If you wrote the comment you can always see the score (0 now, FWIW). At least I've always been able to; hidden comment scores arrived a while after I'd already amassed a pretty high karma level.

It's also very normal for viruses to become more mild over time.

We strongly react to strong threats. It's in the viruses interest to become a weaker threat like the common cold so we tolerate it instead of actively fighting it.

They can also become much more deadly. The first pass of the 1918 pandemic was not nearly so bad as the second, which slaughtered millions of people in their 20s and 30s.

That's a much rarer course and seems to be related to the conditions of WW1. Under normal circumstances, people with mild illnesses are out and about and able to spread the virus, while people with severe illnesses are confined to a bed or hospital and tend to result in an evolutionary dead end. As a result, the descendants of mild cases outcompete the descendants of severe cases, and eventually natural selection results in the dominant strains of the virus all being mild.

With the 1918 flu pandemic, mild cases of flu remained with their unit, while extremely sick cases were transported home via train for improved medical care. As a result, it was the severe cases that ended up sparking new infections, while the mild cases died out after generating herd immunity within an army company.

Most respiratory viruses follow the first scenario, although there is a caution there for people who suggest eg. transporting sick people by airliner to regions with fewer cases to make better use of available hospital capacity. Ironically asymptomatic transmission is your best friend here: if all transmission is asymptomatic, the strains that get transmitted will be the ones more likely to not cause symptoms.

True. But I have heard that that was because, among all the soldiers in the trenches, it could be virulent and still be able to spread effectively, so it had no selection pressure to not be virulent.

Covid is a bit different, because it has a longer incubation time, but that wasn't the issue with the 1918 influenza outbreak.

(Note well: I am not an epidemiologist.)

Even if the whole world was in sync, you more or less have to hold Re below 1 forever or accept that 1-1/Re of everyone gets the virus. That's basically a tautology. But Re can be affected a lot by testing and tracing when the infected population is tiny compared to your resources, and not so much when it is huge. Re could also be affected a lot if we had a vaccine, which will probably take years in the current regulatory regime but is something that might actually benefit from disparate international approaches.

It wouldn't be crazy to ask international travelers to pay the marginal cost of extra testing and/or the negative externality of spreading the virus between worse and better controlled regions.

1) buy time by reducing Re

2) invest into medical research

3) hope you can manufacture something effective by the time the next wave hits

Don't think y our 1-1/R0 rate makes sense (I assume Re is equivalent to R0 - I'm not familiar with Re). At an R0 of 1, each person spreads to one other person. So everyone would eventually be infected, just at a linear rate. Your formula though gives 1-1/1 = 0. Similarly for an R0 less than 1 your formula goes negative.

Anyway, if R0 can be brought below 1, it wouldn't need to be indefinite. The further below 1 it is, the faster the virus will extinguish itself. This was seen in China, where they went from exponential growth to fewer new cases each day and ultimately to the situation now where most new cases are imported from other countries.

You also don't need global coordination, although it helps. Any individual country can restrict outside travel from outbreak areas, get their own R0 below 1 via social distancing to eliminate the local outbreak, and then relax social distancing locally, relying on travel restrictions and temporary quarantines of travelers from outbreak areas, plus testing and contact tracing. If cases start to flare up again, increased social distancing measures can be brought in to get them back under control.

So in theory you could do extreme distancing for a period on the order of a few months, and then normalize somewhat. It would take a global response of that sort (unlikely), a vaccine, or a change in the virus itself though to end the situation entirely.

At an R0 of 2, with no interventions, eventually half the population has had the virus and (hopefully) gained immunity. Now each person only spreads it to 1 other person, because the other person they would have infected is immune. (If R0 was 1, the epidemic would end as soon as the next person in the chain is immune.) This is where the people saying that the virus will definitely eventually infect 70% of everyone are coming from.

Re is effective spread rate, taking into account natural immunity, vaccination, contact tracing, etc. By definition, if Re>1 the epidemic is growing exponentially and if less it is shrinking.

>So what are you going to do when the virus is gone in your city/state/country, isolate yourself from the rest of the world

Yes, that or have 2-4% of the infected population die...

Or more, since this amount of people die only when sufficient care is available. If you interpret the "requires hospitalization" percentage as "will die without hospitalization" (which I'm not 100 % sure is true), as many as 15 or 20 % people can die.

15-20% don't require hospitalization. More were hospitalized to be monitored, but only about 40/705 infected from the Diamond Princess ever progressed to serious condition. And the population of cruise ships skews older.

Hopefully someone is manufacturing a billion masks somewhere in the USA.

I'm hesitant to put this out there but selfish game theory would be to go out and get it now, before all ICU beds are filled so that if you need a bed you can still get one...

It's too late for that. If you exposed yourself now, you'd be direly sick just as the first unhandleable wave is going to hit the health care system.

I suppose it might be possible to get 'ahead of the curve' by having a confirmed infected person sneeze directly in your face, but yeah, it would royally suck to end up needing an ICU in a week or two from now. Doesn't seem worth the risk.

Do we know this? How?

From where I'm sitting, it feels just as plausible that it had mostly hit far larger saturation than people realize. Such that, even if this works, it should have been done literally months ago.

My perspective is someone in Seattle that almost certainly had this a month ago

Getting Re below 1 seems like the right approach, but I really hope that we can do this through extensive testing and travel restrictions. This way anyone who gets any illness and can be tested immediately, tell their friends to get tested, and isolate themselves. Meanwhile the rest of society can function more or less normally, even if they have to watch sports on TV instead of live, and after a sick individuals recover they can be retested and rejoin society again. This seems so much better to me having everyone spend 18 months in moderate isolation until a vaccine is approved.

At least summer is coming and it's substantially safer to be with people outside.

Sounds like we will need the suggestion in this article just to ramp up mask production. And the willingness to make mask wearing mandatory by law. There are too many idiots out there who will not do it otherwise.

Exactly. I find it strange how otherwise highly creative and open-minded people don't see this. Based on other country's experiences you could get this reasonably under control with some rather draconian measures (that might cost 1%+ of GDP to hold), but far less than total shut-down. examples:

1. Remove all testing bottlenecks.

2. Mandate face mask usage in all public settings.

3. Maintain massive queryable databases of cell phone location data for everyone. Goal is to easily find all potentially infected people if you identify a new case.

4. Keep mass gatherings (sports, conferences) closed due to difficulty contact tracing. (until number is really down)

Note that because so many countries screwed up already, a short term lockdown is necessary. But the above is how you handle life after

I don't think people are rejecting those ideas so much as ignoring them for the moment. It's too late for planning, we need a solution now, and mass para-quarantine is really the only tool that can be deployed.

By all means let's investigate other options once the first wave is under control. But right now the first wave is growing out of control in basically every western democracy.

#StayHome now, then work on a better plan. Make it work first before you make it work fast, basically.

Exactly, let’s not focus on premature optimization. Let’s ensure our hospitals don’t get overwhelmed these next few months.

After that, the virus may go away on its own, or it might mutate into a weaker form. Or we might have treatments on the way.

Of those, only the third is likely. There is some hope still that the transmission rate will drop over the summer. But realistically, the post-quarantine phase will be defined by careful monitoring, a bunch of still-extant rules, and the occasional surprise outbreak. And this will go on until either we all get it or until we all get a vaccine.

At some point the testing bottlenecks are real. You can't just remove them. South Korea has tested 0.5% of their population.

Masks production can be increased. But you need hundreds of millions a day of production and won't get there in a short period of time.

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