Age-Stratified SARS-CoV-2 Infection Fatality Rates in New York City estimated from serological data

Rickards, C. G.; Kilpatrick, A. M.

Importance: COVID-19 has killed hundreds of thousands of people in the US and >1 million globally. Estimating the age-specific infection fatality rate (IFR) of SARS-CoV-2 for different populations is crucial for assessing the fatality of COVID-19 and for appropriately allocating limited vaccine supplies to minimize mortality. Objective: To estimate IFRs for COVID-19 in New York City and compare them to IFRs from other countries. Design, Setting, Participants: We used data from a published serosurvey of 5946 individuals 18 years or older conducted April 19-28, 2020 with time series of COVID-19 confirmed cases and deaths for five age-classes from the New York City Department of Health and Mental Hygiene. We inferred age-specific IFRs using a Bayesian framework that accounted for the distribution of delay between infection and seroconversion and infection and death. Main Outcome and Measure: Infection fatality rate. Results: We found that IFRs increased approximately 77-fold with age, with a nearly linear increase on a log scale, from 0.07% (0.055%-0.086%) in 18-44 year olds to 5.4% (4.3%-6.3%) in individuals 75 and older. New York City IFRs were higher for 18-44 year olds and 45-64 year olds (0.58%; 0.45%-0.75%) than Spanish, English, and Swiss populations, but IFRs for 75+ year olds were lower than for English populations and similar to Spanish and Swiss populations. Conclusions and Relevance: These results suggest that the age-specific fatality of COVID-19 differs among developed countries and raises questions about factors underlying these differences.