A group of scientists and economists has devised a simple, tunable strategy for achieving exponential decrease in the number of new cases of Covid-19 while partially reopening the economy — or so it seems to me. The simplest form of the strategy is to alternate between consecutive days of work and consecutive days of lockdown. Although I am reluctant to add to the cacophony of inexpert opinions on how to deal with the pandemic, I will say that the strategy obviously works in an epidemiologic sense if the number of workdays per two-week cycle is sufficiently small. Furthermore, it is obvious that the number of workdays can be adjusted in response to the number of new cases. However, it is not obvious that can be set sufficiently high for the strategy to work in an economic sense. Modeling reported in the preprint “Cyclic Exit Strategies to Suppress COVID-19 and Allow Economic Activity” indicates that is likely to be sufficiently small. In other words, it seems that people might work half-time ( hours per two-week period) while driving the number of new cases toward zero. I am not qualified to judge epidemiological models, but will note that the results make sense if it is indeed the case that there is a “three-day delay on average between the time a person is infected and the time he or she can infect others.”

To be perfectly clear, I have not become a true believer in a strategy addressed in a preprint. I am saying that we should reject the notion that the pandemic will end only with herd immunity. It is not irrational to say that there may be, in the absence of an effective vaccination program, practicable methods of preventing most people from being infected, and that we should keep looking for them.