The researchers used contact tracing data to identify and analyze clusters of infection in Hong Kong for evidence of superspreading events (SSEs). They looked at laboratory-confirmed cases as of April 28, 2020 from the Centre for Health Protection (CHP) of the Department of Health in Hong Kong.

With a superspreading threshold of 6-8 secondary cases, 5-7 probable superspreading events were identified in Hong Kong using contact tracing data. Overall, 20% of cases were estimated to be responsible for 80% of local transmission/cases. Social exposures produced a greater number of seconday cases than work or family exposures (p<0.001).