Nationwide Situation
Tested Positive
Data source: MHLW Open Data. On and after 8 May, the data source was changed. See this link or notes below for further information. READ MORE
Active Cases
Data source: MHLW Open Data. On and after 8 May, the data source was changed. See this link or notes below for further information. READ MORE
Discharged
Data source: MHLW Open Data. On and after 22 April, cases which MHLW is still confirming reports from prefectures are included. On and after 8 May, the data source was changed. See this link or notes below for further information. READ MORE
Critically Ill
Data source: "Coronavirus disease 2019 (COVID-19) situation within and outside the country" > "Critically ill" by MHLW. The former title was "Hospitalized with a ventilator or intensive care unit". See this link or notes below for further information. READ MORE
Deaths
Data source: MHLW Open Data. On and after 22 April, cases which MHLW is still confirming reports from prefectures are included. On and after 8 May, the data source was changed. The number of deaths on June 19 includes the 13 patients who were PCR tested positive but died from diseases other than COVID-19 before that day in Saitama. See this link or notes below for further information. READ MORE
PCR Tested
Data source: MHLW Open Data. On and after 3 March, tests for those who have been in close contact with infected person are included. On and after 29 September, the number does not have continuity with the past because Fukuoka started including tests by private facilities. See below for further information such as definition or notes.READ MORE
PCR Tests
Data source: MHLW Open Data. On weekends and holidays, the number of PCR tests may be announced as "0" because MHLW did not receive the report, even if tests have been performed. The past data will be corrected if the number of previous tests was known. If not, the number of tests on weekdays and holidays will be added on the next weekday. The most recent few days may not be updated since dates containing "under investigation" items are not displayed. The dates are based on when the results of the tests were known. See below for further information such as definition or notes.READ MORE
Effective Reproduction Number
Formula: (New cases in past 7 days / New cases in 7 days before that) ^ (mean generation time / length of reporting interval). Mean generation time is supposed to be 5 days, and length of reporting interval is supposed to be 7 days. For the purpose of understanding current trends in real time, this formula is simplified and based on reporting dates. Note that this formula is a simplified version and may be affected by reporting delays. Model and supervised by Professor Hiroshi Nishiura of Hokkaido University Graduate School of Medicine. Refer to GitHub repository published by Prof. Nishiura for further details.READ MORE
Tested Positive By Age
"Unknown" includes undisclosed or under confirmation. "Discharged" is the number of people who are tested positive but not dead, critically ill, or hospitalized. The total number of this chart may not match the numbers of "Nationwide Situation" because only data that the MHLW obtained the details such as age group or hospitalization status is published here.READ MORE
Prefectures
Each Prefecture
Tested Positive in
The data is based on transcription of the prefectural disclosures by MHLW. In some prefectures, such as Tokyo, data is corrected from reports by each prefecture. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes.READ MORE
Discharged in
The data is based on transcription of the prefectural disclosures by MHLW. In some prefectures, such as Tokyo, data is corrected from reports by each prefecture. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes.READ MORE
Critically Ill in
The data is based on transcription of the prefectural disclosures by MHLW. In some prefectures, such as Tokyo, data is corrected from reports by each prefecture. Tokyo has changed the data definition on 27 April. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes.READ MORE
Deaths in
The data is based on transcription of the prefectural disclosures by MHLW. In some prefectures, such as Tokyo, data is corrected from reports by each prefecture. The number of deaths on June 19 in Saitama includes the 13 patients who were PCR tested positive but died from diseases other than COVID-19 before that day. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes.READ MORE
PCR Tested in
The data is based on transcription of the prefectural disclosures by MHLW. In some prefectures, such as Tokyo, data is corrected from reports by each prefecture. On weekends and holidays, the number of PCR tests may be announced as "0" because MHLW did not receive the report, even if tests have been performed. The past data will be corrected if the number of previous tests was known. If not, the number of tests on weekdays and holidays will be added on the next weekday. On and after 18 June in Hyogo, 21 June in Shizuoka, and 29 September in Fukuoka, the number includes tests covered by private testing facilities. The number in Tokyo includes medical insurance inspection results from 7 May, Antigen tested positive from 13 May, and Antigen tested negative from from 17 June. See Frequently Asked Questions for further information. Aichi in 3/16-22 excludes number of Nagoya city. Akita in 3/11 is the number of only Akita city. The figures for Chiba are only counted from 3/21, Osaka from 3/22. Data on and after 1 July in Kanagawa has been changed as the prefecture corrected the past data. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes. READ MORE
Effective Reproduction Number in
In prefectures with fewer cases, a few case variations may bring a large fluctuation of effective reproduction number. In uncountable cases, such as zero new positives in the previous week, the number of effective reproduction number is also assumed to be zero. See chart annotations in "Nationwide Situation" section or footer notes for further information such as definition or notes. READ MORE
Notes: Returnees on government charter flights from Wuhan, airport quarantine, and passengers and crew on cruise ships docked in Kanagawa, are excluded. Cases on cruise ship docked in Nagasaki are included in nationwide section but not in Nagasaki. Moving averages are 7-day backward. The number is based on disclosures from each prefecture on and after 8 May, and is confirmed by MHLW before that. It is assumed to be the same as the previous day if not updated. On the days with no continuity from the previous day due to change of standards, "New" number is treated as 0 and the bar color is changed. The number of "Tested Positive" is basically equals to the sum of "Active Cases", "Discharged", and "Deaths", unless it includes confirming cases. Data may be corrected by the developer when it is considered as an obvious misstatement, such as minus value of Tested Positive.
Data source: Press release from MHLW, including data on each prefecture. Only data on Tokyo may be corrected later according to Latest updates on COVID-19 in Tokyo. Used Chart.js to draw charts. Used Japan Map to draw prefectures map. Used icons from Material Design.
Change log and source code: GitHub (fork) | GitHub (original) | Download CSV data
Frequently Asked Questions
Q. Why has the number of people PCR tested in Tokyo increased significantly since May?
A. Because they added tests covered by insurance at medical institutions into the number. The number in Tokyo includes The Tokyo Metropolitan Institute of Public Health (all periods), PCR Center (regional outpatient/inspection center) (from 10 April), medical insurance inspection results (from 7 May), Antigen tested positive from 13 May, and Antigen tested negative from 17 June. Since the Tokyo Metropolitan Government often corrects past data at a later date, while this page updates the latest data everyday as a general, we reflect the correction of past data by Tokyo when we noticed (See GitHub for detailed revisions history).
Q. Why are the total values increasing or decreasing significantly along the way?
A. Because data source has been changed. Until 7 May, data from each prefecture is reported to MHLW in accordance with Infectious Disease Law, and is based on disclosures from each prefecture after that. Since this change caused a loss of continuity on a particular day, the bar on that day is changed its color and "New" value is treated as zero. In addition, the aggregation criteria of Tested Positive, Deaths, Discharged, and PCR Tested were changed and the same process was applied to them. Please see the notes below charts for specific changes and dates.
Q. Why some items such as PCR tests fluctuate greatly from day to day?
A. This is because the actual number fluctuates, or because report to MHLW delays. As of later case, reporting number to MHLW tend to be lower in weekends and holidays. Numbers on weekends and holidays may be corrected later, or reported on the most recent weekday. In order to smooth out fluctuation due to the day of the week, each chart has moving average (7-day backward).
Q. Why do some values record minus, even though they should not be?
A. It happens when the past data was corrected. Since MHLW only discloses the latest total number of each items, only values on the latest day are corrected when the past numbers contain errors.
Q. What is Effective Reproduction Number?
A. Effective Reproduction Number (ERN) is an index to see how many people are infected by one carrier. The calculation formula is "(number of new cases in the last 7 days / number of new cases in 7 days before that) ^ (average generation time / reporting interval)". In this page, the average generation time is assumed to be 5 days, and the reporting interval is assumed to be 7 days. In order to understand infection trends as soon as possible, this formula is a simplified version based on reporting date. Note that this index is not a precise calculation and may be affected by delays in reporting. This is based on a model and supervised by Professor Hiroshi Nishiura (Department of Hygiene, Graduate School of Medicine, Hokkaido University). Refer to GitHub Repository published by Professor Nishiura for further details. An increase in this indicator means the infection is spreading rapidly. On the other hand, if it continues to be less than 1, it means that the infection is on the phase of receding. Note that this indicator may be the same in spite of the number of people infected in the last 7 days. To understand the current status of the infection, check other indicators such as the number of positive cases.
Q. What is the definition of "Critically Ill"?
A. On and before 7 May, it means cases putting on a ventilator or treated in an Intensive Care Unit (ICU). Since the number is a total of reports from prefectures after that, the definition may vary by prefecture.
Q. Why are some data different from other press?
A. It depends on the individual case, but it is often due to several of the following: difference of data source (report from MHLW or prefecture), difference of time to close aggregation, or difference of aggregation range (including cases in cruise ships and airport quarantine or not).
Q. How can I access data sources?
A. The latest information page in English by MHLW is here: About Coronavirus Disease 2019 (COVID-19)
Q. Can I use data and source code on my SNS or blog?
A. Yes. Feel free to use it for both commercial or non-commercial use. However, you must indicate the copyright holder, as '東洋経済オンライン「新型コロナウイルス 国内感染の状況」制作：荻原和樹' or 'Toyo Keizai Online "Coronavirus Disease (COVID-19) Situation Report in Japan" by Kazuki OGIWARA'. Other specific standards are based on the MIT license.
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