The Rationale for Stopping All Government-Mandated Social Distancing Immediately

Epidemiologists universally acknowledge that population immunity is the only way to defeat SARS-CoV2 (the virus that causes COVID-19); population immunity will develop once enough ‘healthy’ individuals have been exposed to and recover from the virus, or once a vaccine has been developed and widely administered. Whereas development of a safe and effective vaccine is at least several months away, and could take years, we need long periods of ‘incomplete’ or ‘partial’ social distancing (but with a tight focus on protecting the most vulnerable members of our society). To put this all into perspective, in their recent SARS-CoV2 / COVID-19 prediction models, Harvard epidemiologists found that “social distancing with 60% reduction in R0 … was so effective that virtually no population immunity was built” (italics added, p. 5). In other words, strong social distancing measures (like those currently in place) are too effective -- no population immunity can be built while they are in effect. Furthermore, attempts at ‘flattening the curve’ with strong social distancing measures did not actually flatten the curve, they merely shifted the curve to a later time period. And, when that later time period occurred during the fall and winter months, the peak increased, resulting in MORE deaths than a ‘do nothing from the beginning’ alternative. (The primary goal of flattening the curve is to reduce the magnitude of the infection peak, to keep from overwhelming local healthcare resources.)

R0 (pronounced “are naught”) is the ‘basic reproduction number’ for a virus, which represents the number of people (on average) who one infected person will directly infect. As such, R0 is a direct indication of the level of contagiousness of the virus. For example, the R0 for a measles outbreak is 12 to 18, for the common cold is 2 to 3, and for seasonal influenza it is 0.9 to 2.1. Although each virus has its own characteristic range for R0, the value can be different under different circumstances. For example, R0 values for HCoV-OC43 and HCoV-HKU1 (two coronaviruses associated with the common cold) vary from 2.2 over the winter months to 1.7 in the summer. The maximal (i.e. winter) R0 for SARS-CoV2 has been estimated to be between 2.2 and 2.6. Whenever R0 is less than 1.0, the outbreak of the virus will quickly come to an end (because fewer people are catching the virus than those who are recovering from it).

So how effective has our nation’s recent social distancing been with respect to reducing R0? I know of no definitive calculations that have yet been performed, but my (engineering, non-epidemiologist) guess is that we have reduced R0 by more than 60%. No doubt though, when this pandemic is over and behind us, epidemiologists will be able to use the worldwide data from the past few months and the upcoming months to answer that question.

We also do not yet know the extent to which R0 for the SARS-CoV2 virus will be attenuated over the summer months. However, the aforementioned Harvard epidemiologists developed a model where they used the seasonal fluctuations of R0 for two other coronaviruses to predict the likely seasonality of SARS-CoV2. Based on that analysis, they predicted a 40% natural reduction in R0 for SARS-CoV2 during the summer months. In addition, when they specifically analyzed the effects of sustained social distancing measures (i.e. those lasting 4 to 20 weeks), they found that ‘moderate’ measures (i.e. 20% to 40% reduction in R0) were more effective than ‘strong’ measures (60% reduction in R0).

So, just to recap with a concise overview, here is why we need to immediately eliminate all government-mandated social distancing:

• Population immunity is critical to defeating SARS-CoV2 (and COVID-19, the deadly disease it causes). 
• ‘Strong’ social distancing measures (like those that have been in place the past several weeks) are too effective -- virtually no population immunity can be built while they are in effect. 
• ‘Moderate’ social distancing measures (20% to 40% reduction in R0) provide the ‘sweet spot’ allowing the build-up of population immunity without overstressing local healthcare resources. (NOTE: I have published a parallel blog post explaining the benefits of locally managing social-distancing measures with on/off triggers, to prevent exceeding the capacity of local healthcare resources, as recommended by the Harvard epidemiologists cited above.) 
• The natural summer reduction in R0 for SARS-CoV2 is predicted to be around 40% (i.e. in the complete absence of any social distancing measures). This is right in the ‘sweet spot’ mentioned above. 
• Local communities (like Stillwater) have done an excellent job of increasing their critical care capacity over the past few weeks. 
• Local businesses and community members can be trusted to maintain appropriate levels of social distancing (and those levels can be informed by locally-managed on/off triggers directly tied to local healthcare capacity).

Steve Trost is Associate Director of the Institute for the Study of Free Enterprise and can be contacted at trost@okstate.edu.  He has a bachelor’s degree in engineering from MIT, a master’s degree and PhD in engineering from Oklahoma State University and a PhD in entrepreneurship (also from OSU).

Follow Dr. Trost on twitter: @TrostParadox



Disclaimer: All comments, observations, and statements presented herein represent the opinions of the author and in no way reflect the views of Oklahoma State University or the Institute for the Study of Free Enterprise.