A systematic review and meta-analysis of published research data on COVID-19 infection-fatality rates

Highlights • COVID-19 infection-fatality rate (IFR) is an important statistic for policy about the disease. • Published estimates vary, with a ‘true’ fatality rate hard to calculate. • Systematically reviewing the literature and meta-analyzing the results shows an IFR of 0.68% (0.53-0.82%). • This rate was variable from place to place, with a lower range of 0.17% and a highest estimate of 1.7%. • Serology studies with a lower risk of bias appeared to demonstrate a higher IFR than those at a higher risk of bias.

An important unknown during the COVID-19 pandemic has been the infection-fatality rate (IFR). This differs from the case-fatality rate (CFR) as an estimate of the number of deaths as a proportion of the total number of cases, including those who are mild and asymptomatic. While the CFR is extremely valuable for experts, IFR is increasingly being called for by policy-makers and the lay public as an estimate of the overall mortality from COVID-19. Methods Pubmed, Medline, SSRN, and Medrxiv were searched using a set of terms and Boolean operators on 25/04/2020 and re-searched 14/05/2020, 21/05/2020, and 16/06/2020. Articles were screened for inclusion by both authors. Meta-analysis was performed in Stata 15.1 using the metan command, based on IFR and confidence intervals extracted from each study. Google/Google Scholar was used to assess the grey literature relating to government reports. Results After exclusions, there were 24 estimates of IFR included in the final meta-analysis, from a wide range of countries, published between February and June 2020. The meta-analysis demonstrated a point-estimate of IFR of 0.68% (0.53-0.82%) with high heterogeneity (p