Estimating The Infection Fatality Rate Among Symptomatic COVID-19 Cases In The United States

Knowing the infection fatality rate (IFR) of novel coronavirus (SARS-CoV-2) infections is essential for the fight against the coronavirus disease (COVID-19) pandemic. Using data through April 20, 2020, I fit a statistical model to COVID-19 case fatality rates over time at the US county level to estimate the COVID-19 IFR among symptomatic cases (IFR-S) as time goes to infinity. The IFR-S in the US was estimated to be 1.3 percent. County-specific rates varied from 0.5 percent to 3.6 percent. The overall IFR for COVID-19 should be lower when I account for cases where patients are asymptomatic and recover without symptoms. When used with other estimating approaches, my model and estimates can help disease and policy modelers obtain more accurate predictions for the epidemiology of the disease and the impact of various policy levers to contain the pandemic. The model could also be used with future pandemics to get an early sense of the magnitude of symptomatic infection at the population level before other direct estimates are available. Substantial variation across patient demographics likely exists and should be the focus of future studies.