may 2020 • medRxiv

The infection fatality rate of COVID-19 inferred from seroprevalence data

John Ioannidis

DOI: 10.1101/2020.05.13.20101253

Content curation::David Rodrigues

Key message

Esta é uma revisão narrativa que tem as limitações impostas pela fraca qualidade dos dados provenientes dos vários estudos. A taxa de mortalidade por infecção do COVID-19 pode variar substancialmente (0,03 a 30%) em diferentes locais e isso pode refletir diferenças na estrutura etária da população e na combinação de casos de pacientes infectados e falecidos, além de vários outros fatores. O Professor Armando Brito de Sá resume de forma perfeita este tipo de estudos - "É tentar descrever o elefante pela distribuição de meia dúzia de pêlos deixados cair pelo animal a caminho do bebedouro. As conclusões são inúteis e limitam-se a constatar algo que não chega a ser falso porque não se sabe minimamente onde pára a verdade."

Abstract

Objective To estimate the infection fatality rate of coronavirus disease 2019 (COVID-19) from data of seroprevalence studies. Methods Population studies with sample size of at least 500 and published as peer-reviewed papers or preprints as of May 12, 2020 were retrieved from PubMed, preprint servers, and communications with experts. Studies on blood donors were included, but studies on healthcare workers were excluded. The studies were assessed for design features and seroprevalence estimates. Infection fatality rate was estimated from each study dividing the number of COVID-19 deaths at a relevant time point by the number of estimated people infected in each relevant region. Correction was also attempted accounting for the types of antibodies assessed. Results Twelve studies were identified with usable data to enter into calculations. Seroprevalence estimates ranged from 0.113% to 25.9% and adjusted seroprevalence estimates ranged from 0.309% to 33%. Infection fatality rates ranged from 0.03% to 0.50% and corrected values ranged from 0.02% to 0.40%. Conclusions The infection fatality rate of COVID-19 can vary substantially across different locations and this may reflect differences in population age structure and case-mix of infected and deceased patients as well as multiple other factors. Estimates of infection fatality rates inferred from seroprevalence studies tend to be much lower than original speculations made in the early days of the pandemic.