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Excess all-cause mortality provides an estimate of the additional number of deaths within a given time period in a geographical region (e.g. country), compared to the number of deaths expected (often estimated using the same time period in the preceding year or averaged over several preceding years). In encompassing deaths from all causes, excess mortality overcomes the variation between countries in reporting and testing of COVID-19 and in the misclassification of the cause of death on death certificates. Under the assumption that the incidence of other diseases remains steady over time, then excess deaths can be viewed as those caused both directly and indirectly by COVID-19, COVID-19 pharmaceutical interventions and/or COVID-19 non-pharmaceutical interventions, giving a summary measure of the ‘whole system’ impact.1).