Over- and under-estimation of COVID-19 deaths

The ratio of COVID-19-attributable deaths versus true COVID-19 deaths depends on the synchronicity of the epidemic wave with population mortality; duration of test positivity, diagnostic time window, and testing practices close to and at death; infection prevalence; the extent of diagnosing without testing documentation; and the ratio of overall (all-cause) population mortality rate and infection fatality rate. A nomogram is offered to assess the potential extent of over- and under-counting in different situations. COVID-19 deaths were apparently under-counted early in the pandemic and continue to be under-counted in several countries, especially in Africa, while over-counting probably currently exists for several other countries, especially those with intensive testing and high sensitization and/or incentives for COVID-19 diagnoses. Death attribution in a syndemic like COVID-19 needs great caution. Finally, excess death estimates are subject to substantial annual variability and include also indirect effects of the pandemic and the effects of measures taken.

Automated summary

The ratio of COVID-19-attributable deaths versus true COVID-19 deaths depends on various factors and is currently leading to under-counting in some countries while possibly over-counting in others. Caution is needed in attributing deaths in syndemics like COVID-19.