We could extract data and calculate IFR on another 84 age-strata observations from 19/23 seroprevalence surveys (three had no mortality data for any eligible non-elderly age stratum (25, 30, 35) and one sampled no individuals <65 years of age (44)). The 19 surveys came from 11 countries. For the age group 0-19 years, only five studies had sampled participants for seroprevalence in the corresponding age group (24, 29, 31, 38, 41); for the other studies, the closest available age group was used. Across all countries (Figure 3), the median IFR was 0.0027%, 0.014%, 0.031%, 0.082%, 0.27%, and 0.59%, at 0-19, 20-29, 30-39, 40-49, 50-59, and 60-69 years, using data from 9, 9, 10, 9, 11, and 6 countries, respectively. Appendix Figure 1 visualizes these estimates against other, previously published evaluations of age-specific IFR.
Figure 3.Infection fatality rates in younger age groups derived from included seroprevalence studies.
IFRs are corrected for unmeasured antibody types. Sample size weighted IFRs were calculated for countries with multiple estimates available. * Infinite values produced by zero death counts.