https://www.who.int/bulletin/online_fir ... 265892.pdf
Infection fatality rate of COVID-19 inferred from
seroprevalence data
John P A Ioannidisa
Meta-Research Innovation Center at Stanford (METRICS), Stanford University, 1265 Welch Road,
Stanford, California 94305, United States of America.
Correspondence to John P A Ioannidis (email:
[email protected]).
(Submitted: 13 May 2020 – Revised version received: 13 September 2020 – Accepted: 15 September 2020
– Published online: 14 October 2020)
Abstract
Objective To estimate the infection fatality rate of coronavirus disease 2019 (COVID-19)
from seroprevalence data.
Methods I searched PubMed and preprint servers for COVID-19 seroprevalence
studies with a sample size 500 as of 9 September, 2020. I also retrieved additional results
of national studies from preliminary press releases and reports. I assessed the studies for
design features and seroprevalence estimates. I estimated the infection fatality rate for
each study by dividing the number of COVID-19 deaths by the number of people estimated
to be infected in each region. I corrected for the number of antibody types tested
(immunoglobin, IgG, IgM, IgA).
Results I included 61 studies (74 estimates) and eight preliminary national
estimates. Seroprevalence estimates ranged from 0.02% to 53.40%. Infection fatality rates
ranged from 0.00% to 1.63%, corrected values from 0.00% to 1.54%. Across 51 locations,
the median COVID-19 infection fatality rate was 0.27% (corrected 0.23%): the rate was
0.09% in locations with COVID-19 population mortality rates less than the global average
(< 118 deaths/million), 0.20% in locations with 118–500 COVID-19 deaths/million people
and 0.57% in locations with > 500 COVID-19 deaths/million people. In people < 70 years,
infection fatality rates ranged from 0.00% to 0.31% with crude and corrected medians of
0.05%.
Conclusion 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 and other factors. The inferred infection fatality rates
tended to be much lower than estimates made earlier in the pandemic.
olating across age groups.
Acknowledging these limitations, based on the currently available data, one may project
that
over half a billion people have been infected as of 12 September, 2020, far more than the
approximately 29 million documented laboratory-confirmed cases. Most locations probably have
an infection fatality rate less than 0.20% and with appropriate, precise non-pharmacological
measures that selectively try to protect high-risk vulnerable populations and settings, the infection
fatality rate may be brought even lower.
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