WHO COVID-19 Excess Mortality Estimation Methodology

The World Health Organisation (WHO) is tracking the impact of the COVID-19 pandemic as it evolves over time.

Aggregate case and death numbers are reported to the WHO and the data is publicly available. The data do not always provide a complete picture of the health burden attributable to COVID-19 or number of lives lost due to the pandemic. This is due to variations in testing, differences in the application of rules for attribution of death and certification, delays in reporting, data gaps systems in many countries.

In addition to the deaths directly attributable to COVID-19, deaths that have occurred or have been averted indirectly due to COVID-19 include those linked to conditions that existed before the pandemic and have resulted in deaths due to health systems being overwhelmed or some patients avoiding healthcare, or linked to mitigation measures that have prevented deaths from non-COVID causes. Indirect deaths due to COVID-19 are not captured in the COVID-19 death numbers reported to WHO.

Considering the challenges posed by using reported COVID-19 data, excess mortality is considered a more and weak health information objective and comparable measure that accounts for both the direct and indirect impacts of the pandemic.