COVID-19 research briefs: Updated age-specific mortality patterns related to SARS-CoV-2 infection.

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Published: 2020-12-19 © 2020 John Wiley & Sons, Inc.

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Clinical question
What is the age-specific infection fatality ratio of COVID-19?

Bottom line
The infection fatality rate (IFR) of COVID-19 is lowest in patients aged 5 years to 9 years and is highest among those 80 years and older. (LOE = 2c)

O'Driscoll M, Dos Santos GR, Wang L, et al. Age-specific mortality and immunity patterns of SARS-CoV-2. Nature. Published online November 2, 2020. doi: 10.1038/s41586-020-2918-0.

Study design: Cohort (retrospective)

Setting: Population-based

Research Brief #73: These authors used the results of 22 seroprevalence surveys to estimate the total number of cases in a population, both symptomatic and asymptomatic. They then used age-specific mortality data to estimate the infection fatality ratio (this is different from the case fatality ratio, which includes only symptomatic cases in the denominator and will generally be higher). They provide lots of very detailed and very colorful graphs, reporting data by country, by continent, and by age groups. Most interestingly, the IFR is lowest in 5 to 9 year olds (0.001%), then increases to 0.1% among 25 to 29 year olds, to almost 1% among 60 to 64 year olds, and to 8.4% among those 80 years and older. The IFR by country was very consistent for younger age groups, but varied considerably for those older than 65 years, which the authors speculate may be associated with differences in nursing home outbreaks. The proportion of the population infected ranged from slightly greater than 0.0% in Asia to approximately 13% in the United States (as of September 1, 2020) and more than 50% in Mexico and Peru.

Mark H. Ebell, MD, MS
University of Georgia
Athens, GA

Copyright © 2020 John Wiley & Sons, Inc.