The Expert Meeting analyzed the outbreak from Wuhan, which became the first wave of COVID-19 in Japan, and discovered the conditions under which clusters occur, "Three C's (3密, San Mitsu)." They concluded that most of the primary cases that touched off large clusters were either asymptomatic or had very mild symptoms, and thought it is impossible to stop the emergence of clusters just by testing many people. The first strategy they hammered out was to avoid places of "Three C's (Closed spaces, Crowded spaces and Close-contact settings)."[1][9][10][11] The main routes of infection were considered to be "contact infection", which is transmitted by touching a substance to which the virus is attached, and "droplet infection", which is transmitted by inhaling droplets from a sneeze or cough.