Data on the recent true infection fatality rate (IFR) of COVID-19 have been difficult to come by. Investigators writing in the Annals of Internal Medicine today have, however, provided us with a solid estimate of the Covid-19 IFR in the state of Indiana for those over the age of 11 years and not living in a nursing home.
They combined prevalence estimates from a statewide random sample of participants who were tested from 25 April to 29 April 2020 for active viral infection and SARS-CoV-2 antibodies with data from the Indiana Dept. of Health on confirmed Covid-19 deaths.
Although nursing home residents were not tested, they represented 54.9% of Indiana’s deaths.
The overall IFR was surprisingly low at 0.26%.
Indianans less than 40 years of age had an extremely small IFR of 0.01% whereas those aged 60 or older had an IFR of 1.71%. The authors point out that the IFR for Covid-19 in the elderly is significantly worse than seasonal flu:
In comparison, the ratio is approximately 2.5 times greater than the estimated IFR for seasonal influenza, 0.8% (1 in 125), among those aged 65 years and older . Of note, the IFR for non-Whites is more than 3 times that for Whites, despite COVID-19 decedents in that group being 5.6 years younger on average.
Whites had an IFR of 0.18%; non-Whites had an IFR of 0.59%.
As I am living in a midwest state not dissimilar from Indiana and I’m over the age of 60 years based on these data I could anticipate a 1.7% chance of dying if I contract Covid-19. However, when I have seen Covid-19 fatality rates broken down by decade of age there appears to be a sharp inflection point above the age of 70. It would be nice to see the Indiana data broken down similarly to help identify what age truly represents a high risk cohort.