over 3.6 billion users on social media platforms, and there will be over 4.4 billion users in 2025 . • Infodemic “Infodemic” as termed by WHO indicates that considerable amount of Fake News on the web and the social media ecosystem cause significant harm. Simple definition of Fake News: false news which is intentionally created as news articles to mislead readers. 1 ”We’re not just fighting an epidemic; we’re fighting an infodemic” WHO Director-General Tedros Adhanom Ghebreyesus proclaimed at the Munich Security Conference.  https://www.statista.com/statistics/278414/number-of-worldwide-social-network-users/
the most in 2020. • Some research organization reported about the strength of diffusion of fake news related to COVID-19; • MMD Lab, a Japanese organization, reports that most people read fake news on COVID-19 . • By 18 July 2020, the International Fact-Checking Network (IFCN) unearthed over 7623 unique fact checked articles . 2  https://mmdlabo.jp/investigation/detail_1889.html  https://www.poynter.org/ifcn/
society. • “Alcohol is a cure for COVID-19”  • “6,000 doctors" say hydroxychloroquine is effective.”  3  https://www.abc.net.au/news/2020-04-28/hundreds-dead-in-iran-after-drinking-methanol-to-cure-virus/12192582  https://www.bbc.com/news/51980731 Researches to understand, detect and mitigate infodemic are required!
of the most widely spread fake news in Japan: “Toilet Paper is in short supply, because of COVID-19.”  • We follow the change in the users’ response to fake news related to toilet paper on Twitter. 4  https://xtech.nikkei.com/atcl/nxt/column/18/01353/070100001/ https://asia.nikkei.com/Spotlight/Coronavirus/Coronavirus-rumors-fuel-panic-buying-of-toilet-paper-in-Japan2 https://www3.nhk.or.jp/news/html/20200302/k10012309761000.html
tweets) including words related to “コロナウィル ス(COVID-19)” • Extracted 533,270 tweets including words related to “トイレットペーパー (toilet paper)” to understand how fake news is spread. • Number of tweets in 2020/03/01 are the maximum: 97,339 tweets 4 20000 0 40000 60000 80000 100000 Number of tweets Date 2020/01/20 02/09 02/29 03/20 04/10 2020/01/20 04/20  ⿃海不⼆夫, 榊剛史, and 吉⽥光男. "ソーシャルメディアを⽤いた新型コロナ禍における感情変化の分析." ⼈⼯知能学会論⽂誌 35, no. 4 (2020): F-K45_1.
news media reported that toilet paper is in short supply in foreign countries (Singapole and Taiwan) 4 https://twitter.com/jbl375537500/status/1226291783727845377 https://twitter.com/afpbbcom/status/1229563722269589510
users posted “COVID-19 has possibility to cause toilet paper shortage in Japan.” (deleted post) However, all these posts are shared less than 20 times. ⇒ This fake news did not have a significant impact and did not reach many people. 4 https://news.yahoo.co.jp/byline/shinoharashuji/20200229-00165350/
situation where toilet paper is out of stock. ⇒ The spread of fact-checking articles caused a shortage of toilet paper?. 4 https://twitter.com/hya3310/status/1232971144845615104 https://twitter.com/mariusu10/status/1234487011265806336
the shortage in toilet paper in Japan. • Before 2/27, In neighboring countries, Toilet paper shortage happened • Around 2/27, some users post the possibility of toilet paper shortage in Japan, however these posts shared less than 20. (low impact) • On 2/27, news media published fact-checking, more than 20,000 shares. • After 2/27, toilet paper was out of stock in Japan. ⇒ Fact-checking sites caused people unease, and made people hurried to buy. This example shows that fake news itself are not necessarily the reason to cause infodemic. 4
(ICWSM Workshop, 2020) • Collecting posts and claims about COVID-19 from social media such as Twitter and Facebook • Labeling is based on some fact-checking sites (IFCN) • Multilingual: 40 languages and 105 Countries 3 Recent Research for Infodemic: Dataset Shahi, G.K. and Nandini, D., 2020. FakeCovid--A Multilingual Cross-domain Fact Check News Dataset for COVID-19. arXiv preprint arXiv:2006.11343.
of the diffusion of information about the COVID-19 on Youtube, Twitter, Instagram, reddit and Gab. • Leverage with epidemic models to fit information spreading from questionable sources. • They investigate that information from both reliable and questionable sources do not present different spreading patterns 3 Recent Research for Infodemic: Understand Patwa, P., Sharma, S., PYKL, S., Guptha, V., Kumari, G., Akhtar, M.S., Ekbal, A., Das, A. and Chakraborty, T., 2020. Fighting an infodemic: Covid-19 fake news dataset. arXiv preprint arXiv:2011.03327.
Languages during Emergency Situation • Competition for two tasks; one is the detection of fake news in English and another is the detection of hostile post in Hindi, related to COVID-19 3 Recent Research for Infodemic: Detection Patwa, P., Bhardwaj, M., Guptha, V., Kumari, G., Sharma, S., PYKL, S., Das, A., Ekbal, A., Akhtar, M.S. and Chakraborty, T., 2021. Overview of constraint 2021 shared tasks: Detecting english covid-19 fake news and hindi hostile posts. In Proceedings of the First Workshop on Combating Online Hostile Posts in Regional Languages during Emergency Situation (CONSTRAINT). Springer. Patwa, P., Sharma, S., PYKL, S., Guptha, V., Kumari, G., Akhtar, M.S., Ekbal, A., Das, A. and Chakraborty, T., 2020. Fighting an infodemic: Covid-19 fake news dataset. arXiv preprint arXiv:2011.03327.
the most important research topics. • The cause of infodemic is not simple, such as the spread of fake news. We give an example of how good intentions have possibility to lead to confusion. • In 2020, there have been some researches to understand and detect fake news related to COVID-19. (hot topic) 4