Table 1.

Measures that can be used to express COVID-19-related mortality

Measure	Definition	Strengths and weaknesses
Probability of death	Percentage of deaths at a certain time point calculated using the Kaplan–Meier method for survival analysis	Strength: observations can be censored in case of loss to follow-up/in absence of information on vital status before the end of follow-up; this allows inclusion of all available information Weakness: the number of infected cases is not taken into account
Mortality rate	Number of deaths from COVID-19 in the population, scaled to the size of that population, per unit of time Typically expressed as cases per 1000 individuals per year (also person-years can be used)	Strengths: can easily be calculated and interpreted; suitable for comparison of populations because it is scaled to the total population size Weaknesses: the number of infected cases is not taken into account; time to death (early or late) or loss to follow-up is not taken into account
Case fatality rate	Proportion of deaths from COVID-19, compared with the total number of people diagnosed with the disease for a particular period Represents a measure of disease severity; most often used for diseases with limited-time courses, such as outbreaks of acute infections	Strength: can easily be calculated and interpreted Weaknesses: asymptomatic and otherwise undiagnosed cases are not taken into account; often calculated while the individual outcome (recovery or death) is known only for a proportion of infected patients
Infection fatality rate	Proportion of deaths from COVID-19 compared with the total number of infected people—including those who are asymptomatic and undiagnosed—for a particular period Similar to case fatality rate, but aims to estimate the fatality rate in both the sick (with detected disease) and healthy (with undetected disease) groups of infected people	Strengths: includes the whole spectrum of infected people, from asymptomatic to severe; recommended as a more reliable parameter for evidence-based assessment of the SARS-CoV-2 pandemica Weakness: it may be difficult to capture asymptomatic and undiagnosed subjects

^aThe Centre for Evidence-Based Medicine, Global COVID-19 Case Fatality Rates, CEBM.