(1/4) Study of #COVID19 in Hong Kong from January to April, showing that the epidemic was characterised by superspreading events. Just 19% of infections were responsible for 80% of secondary cases, and 69% of people did not infect anyone.
https://www.nature.com/articles/s41591-020-1092-0

(2/4) However, interventions in place included school closures, some people working from home, bans of mass gatherings, and near-universal mask wearing.

Had these interventions not been in place, even more superspreading may have occurred.

(3/4) The majority of cases (51%) were linked to one of 137 clusters. The largest cluster (106 cases) was associated with 4 bars, the 2nd largest (22 cases) to a wedding, and the 3rd largest (19 cases) to a temple.

Musicians are thought to have spread the virus between the bars.

(4/4) Because people are often infectious before they develop symptoms, isolating confirmed cases may only be of limited benefit.

However, quarantining the contacts of known cases was highly effective in breaking transmission chains.