UC Santa Cruz

Mortality patterns between different populations vary because of many factors including genetic variation, environmental conditions, and age. The ongoing COVID-19 pandemic has killed nearly 1 million people in the United States and nearly 6 million globally, and has severely affected older populations. Accurately estimating the age-specific infection fatality rate (IFR) of SARS-CoV-2 for different populations is crucial for assessing and understanding the impact of COVID-19 and for appropriately allocating limited vaccines and treatments. We estimated age-specific IFRs of wild-type SARS-CoV-2 using published seroprevalence data and recorded deaths in New York City (NYC) from March to May 2020. We estimated the probability of death given infection using a Bayesian framework that accounted for delays between infection and seroconversion and infection and death. IFRs increased more than 75-fold with age, from 0.07% in individuals between 18-45 years old to 5.3% in individuals over 75. IFRs in NYC were higher than IFRs in England, Switzerland, Belgium, France, and Spain for individuals younger than 65 years old, but similar for older individuals. These results suggest that the age-specific fatality of COVID-19 differs among developed countries and raises questions about factors underlying these differences.