NHK reported that a group of researchers on an MHLW task force on the new coronavirus have drafted a report after analyzing 110 people infected with the virus in Japan, including 10 cluster infections that occurred before Feb. 26. According to the network, the group found that 83 people, or 75.4% of the 110, did not transmit the virus to anyone, and more than half of the 27 people with secondary infections transmitted the virus to only one person. Meanwhile, most of the 11 cases where the virus spread from one patient to two or more people occurred in crowded indoor areas, and included cases where the virus spread from one patient to 9 people and 12 people. In outdoor environments, there were only two cases where the virus spread from one patient to two or more and none where the virus spread from one to four or more people.
Hokkaido University Professor Hiroshi Nishiura reportedly said: “Based on our analysis at this point, there is a risk of infection if people gather in small indoor spaces with stagnant air despite ventilation. People need to refrain from entering environments where they can have conversations with others at close range if they have mild cold symptoms. People may be able to prevent the spread of the virus by avoiding crowded indoor areas, so I hope that organizers will reconsider the necessity of holding events in such environments.”