Acute Mortality

In the GNM, excess acute mortality increased monotonically with onset age for tested disease durations. The results qualitatively align with high short-term mortality in older adults for several infectious diseases, including COVID-19 and influenza. Excess infection fatality rate was defined as the excess probability of death during disease compared with a no-disease control. Older individuals have worse short-term outcomes because higher baseline frailty makes the same imposed damage produce greater immediate hazard. Short-term excess mortality increases with age in the weak-disease limit because mortality rises faster than frailty.