The conference programme included business presentations, workshops, breakout discussions, a welcome reception and meals, team-building games, and a Singapore city bus tour. Seating arrangements (where available) for the conference, and interviews with affected individuals, indicated close interactions between cases. Two groups (B1 and B3, and B4 and B7) were seated at the same tables for a 3-h Chinese banquet-style dinner on Jan 20, 2020, with three and two attendees from China, respectively. Four cases (B1, B3, B4, and B5) were in a 4-h breakout session on Jan 21, 2020, with 41 other participants, including ten from China, of whom three had dined with B1 and B3 or B4 and B7 at the Chinese banquet. Furthermore, the team-building games entailed close physical contact.