May 7, 2020

Estimating the Infection Fatality Rate among Symptomatic Covid-19 Cases in the U.S.

Anirban Basu, Stergachis Family Endowed Director of The CHOICE Institute

Anirban Basu, Stergachis Family Endowed Director of The CHOICE Institute

According to a study released today, Anirban Basu, Stergachis Family Endowed Director of The CHOICE Institute at the UW School of Pharmacy, has developed one of the first models that can estimate the COVID-19 Infection Fatality Rate among symptomatic cases (IFR-S).

The Infection Fatality Rate (IFR) is a critical parameter in understanding the COVID-19 pandemic. Basu, who authored the study, says his goal for the model is to address the measurement errors associated with case fatality ratio using statistical techniques that will allow us to infer about the IFR.

“In general, the focus at the CHOICE Institute has been on knowing the current unknowns rather than forecasts,” he said. “For example, the Infection Fatality Rate among those who are affected today can help to recover the evolution of likely symptomatic cases that were undetected and gain a better understanding about testing coverages.”

Basu’s work aligns with UW’s Population Health Initiative of strengthening communities at home and abroad by delivering effective interventions with greater speed, efficiency and quality.

“Our hope is that our study results can help inform local and national policies that will save lives in the future,” said Basu. “Ultimately, we want this work to advance the health of people around the world.”

Basu also noted that the model should not be viewed as the ‘last word’ on estimating the COVID-19 IFR, but as one of the several methods being used to estimate this and related values. Also, IFR estimates are inherently dynamic in nature, and regular update of these estimates using newer data should be carried out.

A web-platform documenting these statistics at the county level will be made available early next week. Basu hopes that a more accurate estimate for the current unknowns will also help forecast the future unknowns better.

The School of Pharmacy and Basu have developed a website that explores the infection and fatality rates by U.S. counties for people with symptoms. For this study, 116 counties in 33 states had COVID-19 data that fit Basu’s robust criteria for inclusion in the analysis.

UW’s CHOICE Institute Interactive: Explore the county-by-county and national infection fatality rates