(1) Endo, @AdamJKucharski et al. have recently shown that 80% of transmissions seem to be caused by 10% of index cases.
wellcomeopenresearch.org/articles/5-67/…
wellcomeopenresearch.org/articles/5-83/…
docs.google.com/spreadsheets/u…
1) closed space with poor ventilation
2) crowded with many people
3) conversations and vocalization in close proximity (within arm's reach of one another)
4) consuming foods and beverages
see also: