See also: Changes in US data following the new CDC guidelines on "Case" and "Death" definition
Worldometer manually analyzes, validates, and aggregates data from thousands of sources in real time and provides global COVID-19 live statistics for a wide audience of caring people around the world.
Our data is also trusted and used by the UK Government, Johns Hopkins CSSE, the Government of Thailand, the Government of Vietnam, the Government of Pakistan, Financial Times, The New York Times, Business Insider, BBC, and many others.
Over the past 15 years, our statistics have been requested by, and provided to Oxford University Press, Wiley, Pearson, CERN, World Wide Web Consortium (W3C), The Atlantic, BBC, Milton J. Rubenstein Museum of Science & Technology, Science Museum of Virginia, Morgan Stanley, IBM, Hewlett Packard, Dell, Kaspersky, PricewaterhouseCoopers, Amazon Alexa, Google Translate, the United Nations Conference on Sustainable Development (Rio+20), the U2 concert, and many others.
Worldometer is cited as a source in over 10,000 published books and in more than 25,000 professional journal articles and was voted as one of the best free reference websites by the American Library Association (ALA), the oldest and largest library association in the world.
We collect and process data around the clock, 24 hours a day, 7 days a week. Multiple updates per minute are performed on average by our team of analysts and researchers who validate the data from an ever-growing list of over 5,000 sources under the constant solicitation of users who alert us as soon as an official announcement is made anywhere around the world.
Our sources include Official Websites of Ministries of Health or other Government Institutions and Government authorities' social media accounts. Because national aggregates often lag behind the regional and local health departments' data, part of our work consists in monitoring thousands of daily reports released by local authorities. Our multilingual team also monitors press briefings' live streams throughout the day. Occasionally, we can use a selection of leading and trusted news wires with a proven history of accuracy in communicating the data reported by Governments in live press conferences before it is published on the Official Websites.
We provide the source of each data update in the "Latest Updates" (News) section.
Below is a sample of some of the sources we use:
A
Total Cases = reported total cumulative count of detected and laboratory (and sometimes, depending on the country reporting them and the criteria adopted at the time, also clinically) confirmed positive and sometimes - depending on the country reporting standards - also presumptive, suspect, or probable cases of detected infection. Because it represents a cumulative count (rather than a snapshot of the number of current cases at any given time), this number can't decrease. The size of the gap between detected (whether confirmed, suspect or probable) and reported cases versus actual cases will depend on the number of tests performed and on the country's transparency in reporting. Most estimates have put the number of undetected cases at several multiples of detected cases. See also: Change in US CDC "Case" and "Death" definition
Active Cases = (total cases) - (total deaths) - (recovered). This figure represents the current number of people detected and confirmed to be infected with the virus. This figure can increase or decrease, and represents an important metric for Public Health and Emergency response authorities when assessing hospitalization needs versus capacity.
Recoveries = this statistic is highly imperfect, because reporting can be missing, incomplete, incorrect, based on different definitions, or dated (or a combination of all of these) for many governments, both at the local and national level, sometimes with differences between states within the same country or counties within the same state. WHO recommends following the criteria of [symptoms resolve + 2 negative tests within 24 hours] or [symptoms resolve + additional 14 days], but this is only a recommendation. In some countries, when a patient is discharged from the hospital it is counted as "recovered" even if no test is performed. Some health officials now consider anyone who was diagnosed with COVID-19 three or more weeks ago and has not died to be recovered from the disease. In view of this, "Active Cases" and "Closed Cases Outcome" which both depend on the number of recoveries (in addition to an accurate death count and a satisfactory rate of case detection, both of which are lacking in the vast majority of countries) can be affected by this inherent flaw for many countries and for the total worldwide count.
Serious and Critical = similarly to recoveries, it is very imperfect, for many of the same reasons. When 99% of the cases were in China, the figure pretty much corresponded to the Chinese NHC's reported number of "severe" cases. Today, it represents for the most part the number of patients currently being treated in Intensive Care Unit (ICU), if and when this figure is reported.
Total Deaths = cumulative number of deaths among detected cases.
On a daily basis, we encounter an increasing number of reporting issues. Some of these include official governmental channels changing or retracting figures, or publishing contradictory data on different official outlets. National or State figures with old or incomplete data compared to regional, local (counties, in the US) government's reports is the norm, so we try to compensate by collecting the missing data and maintaining an accurate and timely count.
Below we are keeping a log with a partial list of errors, retractions, or major discrepancies (and their explanation) between our numbers and what users could see on other outlets, in the hope to clarify the many inquiries we receive:
Spain
There are many issues with Spanish data, including a number of historical downward adjustments that have not been documented through revised reports (which still show the original - higher - numbers being reported), nor explained.
France
As of April 29, the French Government continues to report unreliable and incorrect data on almost a daily basis. On April 29, they reported a decrease of 1,417 confirmed cases compared to April 28. The Ministry of Health yesterday had reported a different figure compared to that of the Government, and even this figure was 1,504 lower than the previous day (April 27), accompanied by a note informing that they had made a mistake the previous day. For this reason, you may notice fluctuations in French data.
France reported that a portion of the EHPAD and EMS nursing home cases - representing about 33% of the total EHPAD and EMS cases - were confirmed (rather than probable, as the other 67%) and as such are to be considered as already included in the total national case count [source]. The French Government has now started reporting the breakdown between confirmed and probable EHPAD and EMS cases [source]. We have adjusted the historical data for France from April 4 based on this information. On April 3, the French Government had reported 17,827 additional cases and 532 additional deaths from nursing homes that had not been reported previously. On April 2, it had reported 884 additional deaths.
China
On April 17, Hubei Province issued a "Notice on the Correction of the Number of New Coronary Pneumonia Cases Diagnosed and the Number of Diagnosed Deaths in Wuhan" in which it reported 1,290 additional deaths that had not been previously counted and reported, bringing the total number of deaths in Wuhan from 2,579 to 3,869, an increase of 50%, as the result of a revision by the Wuhan New Coronary Pneumonia Epidemic Prevention and Control. As part of this revision, 325 additional cases in Wuhan were also added [source] [source]
United States
April 14: Changes in US data following the new CDC guidelines on "Case" and "Death" definition
Ireland
On April 10, the government of Ireland announced that the figure for new cases today includes test results which had been sent to Germany for testing. As of April 10, "the total figure of those who have been diagnosed with COVID-19 in Ireland now stands at 8,089" [source]
France
On April 3, the French Government reported 17,827 additional cases and 532 additional deaths from nursing homes that had not been reported previously.
On April 2,the French Government reported 884 additional deaths that have occurred in nursing homes over the past days and weeks [source]. The French Government did not initially include these deaths in their official count. Following international standards of correct inclusion, our statistics have included these deaths, adding them to the April 2, 2020 count following the attribution criteria of date of report. If and when the French government determines and communicates the correct distribution of these additional deaths over time, we will adjust the historical data accordingly. A similar issue took place on February 12, when China reported an additional 13,332 new cases in a single day due to a change in how cases were diagnosed and reported in Hubei.
Italy
On March 26, there was a mistake in Italy's Protezione Civile bulletin, on which they had entered 449 deaths for Piedmont instead of the correct number: 499. Consequently, the total number of deaths and cases for March 26 was incorrectly calculated and reported by Protezione Civile.
Worldometer spotted the error, confirmed it by calling Piedmont officials directly, and corrected it for everybody else around the world that rely on our global COVID-19 data.
This discrepancy was clearly due to a typing error by Italy's Protezione Civile, not to Piedmont's new deaths missing in the national report, as incorrectly stated by some media, given that the number of new deaths reported by Piedmont on March 26 was 16, whereas the amount missing was greater than that: 50.
Some of the same media (including La Repubblica and Corriere della Sera in Italy) that on March 26 had changed the number from 662 to 712 after our correction, on March 27 were reporting a daily change of 969 based on March 26 incorrect number of 662. BBC, Bloomberg, The Guardian, were also reporting the wrong number on March 27.
Others, such as The New York Times, Reuters, Financial Times, Sky News, Al Jazeera stayed consistent with the March 26 correction and reported a daily change of 919 new deaths for March 27. Even Italy's Protezione Civile, in its March 27 press briefing specified that 50 deaths of the 969 being reported should be attributed to March 26 count due to an error and later published a new corrected version of its March 26 report.
This was not the first instance in which we were called to clarify that our numbers are correct, while numbers reported by other media outlets were incorrect (and not the other way around as many emails we receive claim).
Italian media were reporting the change in active cases (a lower number) rather than the change in total cases (a higher number), representing it as "newly infected" when, in fact, it represents the "change in active cases." After a few weeks, they understood our explanation and changed their reporting.
Newly infected, meaning the number of people who have tested positive to the virus in the last day, is the number shown on our website, which corresponds to the change in total cases in accordance with the international standards set by the WHO and followed by all countries.
The change in active cases (what Italian media labeled as "newly infected") is the result of the following formula:
(newly infected) - (new deaths) - (new recoveries)
All data, including total cases ("casi totali") is available on Italy's Dipartimento della Protezione Civile official repository
