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. 2025 Dec;19(12):e70154.
doi: 10.1111/irv.70154.

Global Estimates of COVID-19 Morbidity and Mortality: A Cohort Study and Mathematical Model Analysis

Houssein H Ayoub  1 , Hiam Chemaitelly  2   3 , Laith J Abu-Raddad  2   3   4   5
Affiliations
Free article

Global Estimates of COVID-19 Morbidity and Mortality: A Cohort Study and Mathematical Model Analysis

Houssein H Ayoub et al. Influenza Other Respir Viruses. 2025 Dec.
Free article

Abstract

Background: The true extent of the severity and fatality caused by the COVID-19 pandemic remains uncertain. This study provides an approximate estimate of the global disease burden from the pandemic.

Methods: A cohort study followed the Qatari population from the onset of the pandemic to March 18, 2024, to estimate the age-specific incidence rates of severe, critical, and fatal COVID-19, classified according to World Health Organization criteria. A mathematical model then utilized these rates to generate regional and global estimates of COVID-19 severity and fatality.

Results: The incidence rate of any severe, critical, or fatal COVID-19 throughout the pandemic was 1.13 (95% CI: 1.07-1.19) per 1000 person-years, while that of fatal COVID-19 alone was 0.11 (95% CI: 0.09-0.13) per 1000 person-years. Globally, the number of severe, critical, or fatal COVID-19 cases was estimated at 61.9 million (95% UI: 55.0-69.9 million), while the number of fatal COVID-19 cases alone was estimated at 11.3 million (95% UI: 7.8-17.4 million). Both estimates showed large regional variations. Most severe, critical, and fatal COVID-19 cases occurred during the pre-Omicron phase of the pandemic.

Conclusions: The COVID-19 pandemic had a profound global impact on morbidity and mortality, emphasizing the critical need for preparedness for future pandemics.

Keywords: SARS‐CoV‐2; cohort study; epidemiology; fatality; mathematical model; severity.

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