Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of observational prevalence data
PubMed 33289900 · doi:10.1007/s10654-020-00698-1
What was done
Systematic review and meta-regression of COVID-19 prevalence studies published, preprinted, or disseminated as government reports prior to September 18, 2020. Out of 113 identified studies, 27 studies covering 34 geographical locations met inclusion criteria. Age-specific infection fatality rates (IFRs) were calculated by combining prevalence data with fatalities reported 4 weeks after the midpoint date of each study to account for reporting and clinical lags, followed by meta-regression in Stata.
What was found
COVID-19 infection fatality rate increased exponentially with age. Estimated age-specific IFRs were 0.002% at age 10, 0.01% at age 25, 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85. Approximately 90% of the geographical variation in population-level IFR was attributable to differences in population age composition and the extent of viral exposure among vulnerable age groups.
Why it matters
This study quantitatively established the exponential relationship between age and COVID-19 mortality early in the pandemic, demonstrating substantial risk extends into middle-aged adults rather than strictly the oldest cohorts.
Limits
The review was restricted to early-pandemic data prior to September 2020, before widespread vaccination and subsequent viral variants. It relied on variable jurisdictional death reporting and seroprevalence methodologies, and used a fixed 4-week lag assumption to estimate fatalities.
Cited by
- supports The mortality rate of COVID-19 is approximately tenfold higher than that of the common seasonal flu.