Table 3.

Summary of transmission profiles of asymptomatic cases in contact tracing studies

Study	Setting	Sample size	Measurement of relative infectivity of asymptomatic cases
He et al. [15]	Ningbo city, China	52 asymptomatic and 271 symptomatic cases	Ratio of reproduction numbers: 0.26b
Nakajo et al. [16]	Tokyo and Kanagawa, Japan	12 asymptomatic and 24 symptomatic cases	Ratio of reproduction numbers: 0.27 (95% CI: 0.03–0.81)
Sayampanathan et al. [13]	Singapore	3035 contacts of asymptomatic cases and 755 contacts of symptomatic cases	Incidence rate ratio: 0.26b
Chaw et al. [14]	Brunei	106 contacts of asymptomatic cases and 1595 contacts of symptomatic casesa	Attack rate ratio: 1.12c

^a pre-symptomatic cases were counted as symptomatic cases

^b reciprocal of reported values

^c calculated manually from Supplementary Table 1