Modeling COVID-19 Escalations: Recommended Simulator

by John S. Marr, MD, MPH, and Lloyd F. Novick, MD, MPH


Over the past few decades, we have become acquainted with models predicting the path of hurricanes. Now, over the last few weeks, we have become inundated with numerous graphs and “modelings” of COVID-19 escalations. They have become a regular part of the White House briefings. Dr. Tony Fauci does not rely on models for COVID-19 because the assumptions are flawed. He also notes the worst case scenarios fortunately never occur. 

“There are things called models, and when someone creates a model, they put in various assumptions. And the model is only as good and as accurate as your assumptions. And whenever the modelers come in, they give a worst-case scenario and a best-case scenario. Generally, the reality is somewhere in the middle. I’ve never seen a model of the diseases that I’ve dealt with where the worst-case scenario actually came out. They always overshoot.” ~ Dr. Anthony Fauci, Real Clear Politics, March 29, 2020

This presentation by Grant Sanderson at 3blue1brown offers an outstanding understanding of this discipline. It shows how modeling for COVID-19 actually works. It is based on the inputs. How these inputs vary will predict the apex and duration of the epidemic curve as well as the effect of public health control measures on the outcomes. The advantage of this presentation is that it illustrates the dynamics of modeling and how as the factors vary, so do the outcomes. It also provides guidance on the best public health measures to stem the pandemic. This modeling shows us that the most effective strategy to address spread of disease is identifying and isolating individuals with infections. Also of importance is testing contacts of infected individuals. These are basic public health measures. Mitigation techniques, including social distancing and quarantine, are also recommended. But to the extent that they are “leaky,” or imperfect with respect to containing infected individuals, the epidemic curve can be prolonged, and the number of total cases may increase over time. 

It is well worth the ten minutes to see this video once. Or twice.

Consider yourself as a host and vector of this valuable agent of information and “spread” it to your colleagues and friends.

Source: Grant Sanderson at 3blue1brown

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Dr. John S. Marr is an American physician, epidemiologist, and author. His professional life has concerned outbreaks of infectious disease and thus his subsequent writing career has focused on that topic, particularly historical epidemics. Marr graduated from Yale and received an MD from New York Medical College. He then completed an MPH degree from the Harvard School of Public Health. Marr is a board-certified (internal medicine, preventive medicine, occupational medicine) physician and a Louisiana State University Fellow in Tropical Medicine.

Lloyd F. Novick, MD, MPH is Professor Emeritus of the Department of Public Health at the Brody School of Medicine, East Carolina University. Previously, he was chair of this Department. He has served as the Commissioner of Health and Secretary for Human Services of Vermont, Director of Health Services for Arizona, and Director of the Office of Public Health for New York State. Previous academic positions include Professor and Director of the Preventive Medicine Program for SUNY Upstate Medical University, Professor and Chair of Epidemiology at the University of Albany School of Public Health, and Clinical Professor and Director of the Teaching Program in Epidemiology and Public Health at the University of Vermont, College of Medicine. He is the Founding Editor and Editor-in-Chief of the Journal of Public Health Management and Practice. Follow him on Twitter. [Full bio.]

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