From my email

One thing that some people fail to realize is the following:  This disease will have about the same fraction of population infected plus recovered In the post-lockdown equilibrium regardless of the policy path that gets us there. However, that does not mean that the number of dead is the same for all policies, because the infection fatality rate is so heterogenous with this disease.

The (often unrecognized) elephant in the room is that one set of policies may sort the least vulnerable population to be infected first while another set of policies may sort the most vulnerable population to be infected last.  Protecting the most vulnerable effectively while infecting the least vulnerable quickly could theoretically save almost everyone for this particular disease.

Since the old and sick people often live in relative “lockdown” even at normal times, the general lockdown does the opposite of beneficial sorting by slowing down infections among the least vulnerable.  The general lockdown kills more people over the whole epidemic by tilting the sorting in an unfavorable direction.

The hospital crowding is in my opinion a relatively unimportant issue compared to this because there is no effective “silver bullet” therapy for the disease.

That one is anonymous!  And from another reader:

A lot people are citing a paper that looks at the impact of general lockdowns on ultimate deaths (over 24 month window) during the 1918 Spanish flue epidemic in the US. It’s important to understand that the 1918 epidemic and 2020 epidemic have a sorting effects that go in the opposite direction.

The 1918 disease was most dangerous to people with strong immune systems (young adults), and those people were also the ones that were most active in society and had most interpersonal contacts. Absent any general lockdown, those people were infected first and didn’t benefit from the long-run equilibrium of “herd immunity.” The general lockdowns during the 1918 disease epidemic reduced these vulnerable people’s infection probability relatively more than that of the less vulnerable people.  This improved sorting and thereby saved lives.

The 2020 disease works in the opposite way. It is the most dangerous to old, sick people with weakest immune systems.  Those people are relatively inactive at normal times and don’t have a large number of social contacts. The general lockdown increases those vulnerable people’s relative infection probability, because their routine doesn’t change much while less vulnerable people social distance. This adverse sorting due to general lockdowns causes more deaths, in theory at least.

In my opinion, the 1918 lockdown evidence should be interpreted as evidence of the importance of sorting, not evidence that general lockdowns are the right thing to do now.


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