Infection Fatality Rate (IFR)
\ɪnˈfɛkʃən\ \fəˈtælɪti\ \reɪt\ \(aɪ-ɛf-ɑr)\
The percentage of people infected with a disease (whether symptoms are mild, severe, or even unnoticed) who are expected to die from it.
It differs from the Case Fatality Rate (CFR), which only considers confirmed cases. IFR is harder to estimate accurately because it requires knowing the total number of infections, including those that were never diagnosed.