ourworldindata - Coronavirus Disease (COVID-19) – Statistics and Research
by Max Roser, Hannah Ritchie and Esteban Ortiz-Ospina
We thank Bernadeta Dadonaite, Jason Hendry, and Moritz Kraemer for helpful comments and suggestions on earlier versions of this work.Tom Chivers we would like to thank for editorial review and feedback.
And we would like to thank the many hundreds of you who give us feedback on this work every day.
Your feedback is what allows us to continuously clarify and improve it. We very much appreciate you taking the time to write.
Even if we can’t respond to every message we receive, we do read all feedback and take it all into account.
Note: To inform yourself and understand the risk to the public we recommend to rely on your government body responsible for health and the World Health Organization – their site is here.
The mission of Our World in Data is to make data and research on the world’s largest problems understandable and accessible.
Read more about our mission →
Only on the basis of clearly presented and well-documented data can governments, organizations and individuals hope to respond appropriately to the COVID-19 pandemic. The goal of our work here is to present the best available data and clarify what can – and can not be said – based on this data.
We list all our visualizations – more than 40 in total – on the pandemic on this page.
This article covers a developing situation and the Our World in Data team is updating it daily: The last update was made on April 4, 2020 (11:30, London time).
Even the best existing research and data is preliminary and will be revised as the pandemic progresses.
We reviewed existing global data sources and decided to rely on the global statistics published by the European Center for Disease Prevention and Control (ECDC).
During a disease outbreak it is the growth rate that deserves attention. We present a table that lists how fast the number of deaths is doubling.
In interactive charts we present the data on confirmed deaths in all countries in the world.
Without widespread testing for COVID-19 we can neither know how the pandemic is spreading nor appropriately respond to it.
The total number of COVID-19 cases is not known. It is however certain that the total number of COVID-19 cases is higher than the number of known confirmed cases. This is mainly due to limited testing.
Just as we do for deaths, we focus on the growth rate of confirmed cases. We present a sortable table that lists how fast the number of confirmed cases is doubling.
In interactive charts we present the data on confirmed cases over time in all countries in the world.
The case fatality rate (CFR) – the ratio between confirmed deaths and cases – is widely discussed, but during the outbreak of a pandemic with large unknowns it is important to know what can and cannot be said based on currently available statistics.
We rely on data from the European CDC
In this document and the many embedded and linked charts we report and visualize the data from the European Center for Disease Prevention and Control (ECDC).
The European CDC publishes daily statistics on the COVID-19 pandemic. Not just for Europe, but for the entire world.
The ECDC makes all their data available in a daily updated clean downloadable file. This gets updated daily reflecting data collected up to 6:00 and 10:00 CET. The data made public via the downloadable data file is published at 1pm CET, and is used to produce a page that gets updated daily under the name Situation Update Worldwide.
We discuss our data sources and why we rely on the data from the ECDC rather than other institutions at the end of this article here.
Reported new cases on a particular day do not necessarily represent new cases on that day
The number of confirmed cases or deaths reported by any institution – including the WHO, the ECDC, Johns Hopkins and others – on a given day does not represent the actual number of new cases or deaths on that date. This is because of the long reporting chain that exists between a new case or death, and its inclusion in national or international statistics.
The steps in this chain are different across countries, but for many countries the reporting chain includes most of the following steps:1
Doctor or laboratory diagnoses a COVID-19 case based on testing or combination of symptoms and epidemiological probability (such as a close family member testing positive).
Doctor or laboratory submits report to health department of the city or local district.
Health department receives the report and records each individual case in the reporting system, including patient information.
The ministry or another governmental organization brings this data together and publishes the latest figures.
International data bodies such as the WHO or the ECDC can then collate statistics from hundreds of such national accounts.
This reporting chain can take several days. This is why the figures reported on any given date do not necessarily reflect the number of new cases or deaths on that specific date.