Work out infection fatality rate instantly with clear inputs, formula shown and shareable results.
Scales confirmed cases by an ascertainment multiple to estimate total infections, then divides deaths by that denominator.
Infection fatality rate
IFR (%) = deaths / (confirmed cases x infections per confirmed case) x 100
Seroprevalence surveys, which measure past infection directly and are the standard way to estimate under-ascertainment.
Mortality risk rises roughly exponentially with age for most respiratory infections, so a single IFR hides large variation.