[6] On February 14, 2020, multiple infected people were confirmed among attendees of the New Year's party of a private taxi union branch in Tokyo held on a yakatabune (houseboat) on January 18, 2023.

[7] On March 25, 2020, more than a dozen inpatients and nurses were found to be infected at Eiju General Hospital, the largest in Taitō, Tokyo.

[20] On 2 June 2020, Tokyo Alert was issued due to the risk of infection spreading mainly in downtown areas and hospitals at night.

[22] Journalist Toshinao Sasaki said in a radio program, "I wondered what Tokyo Alert was, so I looked it up on a search engine, but there was neither a site nor news that explained what to do.

[25] Yuriko Koike announced on June 12 that she would end the Tokyo Alert and phased closure request system.

[28] The Tokyo metropolitan government was cautious about reissuing the alert, fearing that economic activity would stagnate again.

Information such as the status of testing and the number of infected people is displayed in a graph -based design, and the latest news and consultation methods are also explained.

In August, a mass infection was confirmed at a restaurant that posted the sticker, and the Tokyo Metropolitan Government said, "We will check to what extent the guidelines have been followed.

[44][45] In January 2020, concerns were raised about the potential impact of the COVID-19 pandemic on athletes and visitors to the Summer Olympic Games.

The IOC stated that in 2020, their Japanese partners and Prime Minister Shinzo Abe "made it very clear that Japan could not manage a postponement beyond next summer [2021] at the latest".

Unlike the case for Zika virus during the 2016 Summer Olympics in Rio de Janeiro, SARS-CoV-2 can be transmitted directly between humans, posing tougher challenges for the organizers to counteract the infectious disease and host a safe and secure event.

Also unlike the case for H1N1 "swine flu" during the 2010 Winter Olympics in Vancouver, COVID-19 has a higher fatality rate, and there was no effective vaccine until December 2020.