Estimates of the Undetected Rate among the SARS-CoV-2 Infected using Testing Data from Iceland

James H Stock; Karl M Aspelund; Michael Droste; Christopher D Walker

• ( = 1| = 0, = 0): As a lower bound, we use the lower bound of λ0 of 0.17%. As an upper bound, we use the proportion symptomatic from Guðbjartsson et al (2020) , 44%, which reflects the assumption that mildly symptomatic individuals will be oversampled in the voluntary deCODE testing. • ( = 1): The COVID-19 website only reports the most updated count of individuals under quarantine, but we require the proportion not quarantined ( = 0) at the time of testing. We use the number of quarantined individuals on March 19, the last day of deCODE testing reported in Guðbjartsson et al (2020) , from the report of the Department of Civil Defense on March 20. 8 • ( = 1) (for use in bounds calculation, odds ratio approach): We sum the number of NUHI tests from March 13 through March 19 from the Health Directorate count data to match the timing of the deCODE testing and the quarantine count figure in the bound analysis, then divide this sum by the population of Iceland. 6