To start, the severity estimates that Joshua assumed were worst case and are implausible. The very alarmist Fergeson et al paper has much lower numbers than Joshua’s claim that “20% will develop a severe case and need medical support to survive.”
I also think you’re wrong about the likely course of the disease, for a couple reasons.
First, as the overload gets worse, therapeutic drugs will become more widely used. I expect that at least a few of the candidates will be at least moderately effective in treating cases, and even though we’ll run out of Remdesivir quickly, production will be ramping up. Chloroquine will be made available widely as well.
Second, R_0 will drop significantly with the community distancing / flattening the curve measures. The line in your diagram is typical capacity—but if the spread is slowed enough to bring extra ventilators and emergency response capacity online, the situation is much less disasterous. Yes, it will be bad, but the worse it is, and the more news coverage there is, the more distancing will happen on its own.
Third, the seasonal component is very uncertain, but is almost certainly non-zero. If spread is slowed due to distancing, R_0 could certainly drop below one by the time the health system is getting overloaded.
For all of those reasons, I think your prescription is alarmist. Good Judgement’s Dashboard has less than a 20% chance of over 350k deaths—that’s a 0.1% population fataility rate. (Full disclosure: I’m forecasting for it, but am currently less pessimistic than the average.)
I’ll address my claims about why not to call for bans or eradication yet in another comment.
To start, the severity estimates that Joshua assumed were worst case and are implausible. The very alarmist Fergeson et al paper has much lower numbers than Joshua’s [Joscha Bach’s] claim that “20% will develop a severe case and need medical support to survive.”
I believe the 20% figure comes from the WHO joint report which says
13.8% have severe disease (dyspnea, respiratory frequency ≥30/minute, blood oxygen saturation ≤93%, PaO2/FiO2 ratio <300, and/or lung infiltrates >50% of the lung field within 24-48 hours) and 6.1% are critical (respiratory failure, septic shock, and/or multiple organ dysfunction/failure).
There are a lot of modeling assumptions that go into this, and the true number is probably lower, but not so low as to invalidate Joscha’s point.
In that report, 13.8% had at least one of those symptoms—that doesn’t imply than many or most would require ICU support to survive.
And event if we assume they would all die, which is wrong, Wuhan was an unlikeley-to-be-repeated worst case scenario—not just because of the medical overload with no warning, or the significant under-diagnosis of lightly symptomatic younger patients inflating the severe case percentage, but because they didn’t realize this was a severe disease for the elderly until at least weeks into the spread. Elderly people globally are now being kept largely isolated, and will be treated aggressively when they get sick initially, instead of treating it like influenza until they are nearly dead.
The population of the Lombardy region is slightly smaller than that of Wuhan, and they are reporting 3x as many daily deahts as China did during their peak.
Right, meaning that the population fatality rate looks like it will end up close to 0.1%, so saying 20% would need medical support to survive is incredibly alarmist.
The diagram with the red line is from Ferguson et al, and is labelled “Surge critical care bed capacity” in their paper.
For all of those reasons, I think your prescription is alarmist.
Why? If we follow a “Flatten the Curve” approach we will take significant casualties as well as significant economic damage. Flatten the curve in Ferguson et al assumes that lockdown lasts until September. The strategy that I endorse is to zero out the curve and eradicate the disease, and I think that some people could be back at work in 6 weeks if we do that, albeit with certain restrictions on travel and events. I would have to look at this a bit more, but it seems to me that an eradication plan will be much less economically costly.
Yes, GJP is predicting 326,000 dead in expectation in the US alone. But I think a large input to that is people rationally expect that if it gets that bad there will be a massive lockdown that lasts for a long time. Lockdowns and deaths are two different costs we are paying, we want to minimize the sum of human plus economic costs.
Yes, the diagram is based on waiting another full month—April 20 - before starting any interventions to reduce this, and assuming an Rp of 2.2 or 2.4 until then. That’s not happening, because they’ve already started much of the proposed interventions, and given that, the curve will already be far lower.
And “flatten the curve” can and will be used as an interim strategy if it is ineffective—this paper assumes that they would have 6,000 people in ICUs before anyone starts asking whether they should start more.
even though we’ll run out of Remdesivir quickly, production will be ramping up. Chloroquine will be made available widely as well.
True, these things will limit the damage in lives if all goes well.
But I think there is a bit of a strategy bifurcation here: if the drugs allow the damage from covid-19 to be minimized to such an extent that we’re happy with the “flatten” strategy—meaning a partial lockdown that helps to slow the virus down but still lets it go through the whole population, then at that point we should probably take some extra casualties and just allow the virus to go through the population as quickly as possible, thereby avoiding months and months of costly lockdowns.
If we are not happy with doing that, we should probably go for eradication.
I don’t see a middle ground where a rational decision-maker would want to run the “flatten” strategy, though we may muddle through to there through indecision and incompetence.
Yes, I’ve noted elsewhere that treatment options might make increased spread more likely, - and it’s unclear that this will be net positive in fact, because as you say, decision-makers will muddle through, and use the existence of treatment as an excuse not to limit spread enough, potentially increasing total deaths despite partially effective treatment.
But your claim that we want to ” just allow the virus to go through the population as quickly as possible ” seems wrong. Imagine (very generously,) that the available treatments reduce the percentage of critical cases by 80%. That means that health care systems can stay under capacity with a flatten strategy, but not with your suggested strategy. For “as quickly as possible” to make sense, we’d need a 95% effective treatment—which is implausible to the point of impossibility with the types of drugs currently being considered.
If the drugs save 80% of critically ill people from dying, then even if the remaining 20% overload the hospital system it might still be worth not trying to flatten the curve, just to avoid the economic damage from the lockdowns.
One would have to do a detailed analysis, but right now I seem to be getting the impression that the drugs actually aren’t that good.
Anyway I still stand behind the point that there is likely to be a strategy bifurcation where it’s best to either go pretty all-in on containment or go pretty all-in on herd immunity/deliberate infection, depending on just how bad it would be.
A 0.1% chance of death is worth about 1-3 months of lockdown, but age-weighting of deaths towards older people and lockdown damage skews this.
Without any change in the numbers I definitely still support containment.
To start, the severity estimates that Joshua assumed were worst case and are implausible. The very alarmist Fergeson et al paper has much lower numbers than Joshua’s claim that “20% will develop a severe case and need medical support to survive.”
I also think you’re wrong about the likely course of the disease, for a couple reasons.
First, as the overload gets worse, therapeutic drugs will become more widely used. I expect that at least a few of the candidates will be at least moderately effective in treating cases, and even though we’ll run out of Remdesivir quickly, production will be ramping up. Chloroquine will be made available widely as well.
Second, R_0 will drop significantly with the community distancing / flattening the curve measures. The line in your diagram is typical capacity—but if the spread is slowed enough to bring extra ventilators and emergency response capacity online, the situation is much less disasterous. Yes, it will be bad, but the worse it is, and the more news coverage there is, the more distancing will happen on its own.
Third, the seasonal component is very uncertain, but is almost certainly non-zero. If spread is slowed due to distancing, R_0 could certainly drop below one by the time the health system is getting overloaded.
For all of those reasons, I think your prescription is alarmist. Good Judgement’s Dashboard has less than a 20% chance of over 350k deaths—that’s a 0.1% population fataility rate. (Full disclosure: I’m forecasting for it, but am currently less pessimistic than the average.)
I’ll address my claims about why not to call for bans or eradication yet in another comment.
I believe the 20% figure comes from the WHO joint report which says
There are a lot of modeling assumptions that go into this, and the true number is probably lower, but not so low as to invalidate Joscha’s point.
In that report, 13.8% had at least one of those symptoms—that doesn’t imply than many or most would require ICU support to survive.
And event if we assume they would all die, which is wrong, Wuhan was an unlikeley-to-be-repeated worst case scenario—not just because of the medical overload with no warning, or the significant under-diagnosis of lightly symptomatic younger patients inflating the severe case percentage, but because they didn’t realize this was a severe disease for the elderly until at least weeks into the spread. Elderly people globally are now being kept largely isolated, and will be treated aggressively when they get sick initially, instead of treating it like influenza until they are nearly dead.
If Wuhan was a worst case scenario, how come Italy has now overtaken it in deaths? (3400 Vs 3200)
The population of Italy is several times higher, and the death rate per case is still significantly lower.
The population of the Lombardy region is slightly smaller than that of Wuhan, and they are reporting 3x as many daily deahts as China did during their peak.
It’s changed substantially since you wrote this BTW. It’s now 54%
Right, meaning that the population fatality rate looks like it will end up close to 0.1%, so saying 20% would need medical support to survive is incredibly alarmist.
Thanks for your comment, David.
The diagram with the red line is from Ferguson et al, and is labelled “Surge critical care bed capacity” in their paper.
Why? If we follow a “Flatten the Curve” approach we will take significant casualties as well as significant economic damage. Flatten the curve in Ferguson et al assumes that lockdown lasts until September. The strategy that I endorse is to zero out the curve and eradicate the disease, and I think that some people could be back at work in 6 weeks if we do that, albeit with certain restrictions on travel and events. I would have to look at this a bit more, but it seems to me that an eradication plan will be much less economically costly.
Yes, GJP is predicting 326,000 dead in expectation in the US alone. But I think a large input to that is people rationally expect that if it gets that bad there will be a massive lockdown that lasts for a long time. Lockdowns and deaths are two different costs we are paying, we want to minimize the sum of human plus economic costs.
Yes, the diagram is based on waiting another full month—April 20 - before starting any interventions to reduce this, and assuming an Rp of 2.2 or 2.4 until then. That’s not happening, because they’ve already started much of the proposed interventions, and given that, the curve will already be far lower.
And “flatten the curve” can and will be used as an interim strategy if it is ineffective—this paper assumes that they would have 6,000 people in ICUs before anyone starts asking whether they should start more.
True, these things will limit the damage in lives if all goes well.
But I think there is a bit of a strategy bifurcation here: if the drugs allow the damage from covid-19 to be minimized to such an extent that we’re happy with the “flatten” strategy—meaning a partial lockdown that helps to slow the virus down but still lets it go through the whole population, then at that point we should probably take some extra casualties and just allow the virus to go through the population as quickly as possible, thereby avoiding months and months of costly lockdowns.
If we are not happy with doing that, we should probably go for eradication.
I don’t see a middle ground where a rational decision-maker would want to run the “flatten” strategy, though we may muddle through to there through indecision and incompetence.
Yes, I’ve noted elsewhere that treatment options might make increased spread more likely, - and it’s unclear that this will be net positive in fact, because as you say, decision-makers will muddle through, and use the existence of treatment as an excuse not to limit spread enough, potentially increasing total deaths despite partially effective treatment.
But your claim that we want to ” just allow the virus to go through the population as quickly as possible ” seems wrong. Imagine (very generously,) that the available treatments reduce the percentage of critical cases by 80%. That means that health care systems can stay under capacity with a flatten strategy, but not with your suggested strategy. For “as quickly as possible” to make sense, we’d need a 95% effective treatment—which is implausible to the point of impossibility with the types of drugs currently being considered.
If the drugs save 80% of critically ill people from dying, then even if the remaining 20% overload the hospital system it might still be worth not trying to flatten the curve, just to avoid the economic damage from the lockdowns.
One would have to do a detailed analysis, but right now I seem to be getting the impression that the drugs actually aren’t that good.
Anyway I still stand behind the point that there is likely to be a strategy bifurcation where it’s best to either go pretty all-in on containment or go pretty all-in on herd immunity/deliberate infection, depending on just how bad it would be.
A 0.1% chance of death is worth about 1-3 months of lockdown, but age-weighting of deaths towards older people and lockdown damage skews this.
Without any change in the numbers I definitely still support containment.