Carsi Model

Interactive map showing the modeled COVID-19 prevalance and death

webgis
public health
Author

Sean C. Ahearn, Shipeng Sun

Published

September 1, 2021

CARSI SIR Model for COVID 19

The CARSI (Center for Advanced Research of Spatial Information) Model uses an embedded recursive SIR (susceptible, infected, removed) model to simultaneously solve for two key epidemiological parameters Ro and the contact ratio (CR). The modeling is based on a set of assumptions including a fatality rate of 0.6 %, an initial infection rate of 0.00125 and a cycle duration of 21 days. It is modeled on fatalities as reported by the New York Times. The model assumes 42 million vaccinations have occurred in the US by February 8, 2021 and will increases as a sigmoidal function to an asuymtote of around 190 million. Each county was assumed to get a pro-rate share of vaccines based on population. Population source was the 2020 US Census estimates. The total projections from the model are calculated by summing up the results from over 3,200 county level models.

To see the model for an individual county, click on a county on either map to the right.

Key findings: Given these assumptions the projected fatality rate for September 15, 2021 is 631,000. Without the attenuating effect of the vaccine the rate was projected to have been 748,605 by May 1, 2021. In essence, almost 190,000 lives were saved due to the introduction of the vaccine as projected by the model out to May 1, 2021. The model projection was made with data from February 21, 2021. The only thing updated was the vaccination model.

Modeling: Sean C. Ahearn, Professor & Director, sahearn@hunter.cuny.edu

Web-mapping: Shipeng Sun, Assistant Professor, shipeng.sun@hunter.cuny.edu

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