Fig. 1: Virological surveillance, participatory syndromic surveillance and behavioural data for model parameterization.
From: Underdetection of cases of COVID-19 in France threatens epidemic control
a, Estimated number of virologically confirmed symptomatic cases in mainland France by week of testing and week of onset (bar graphs), and test positivity rate (line graphs). Estimates are based on the imputation of individuals without symptoms who tested positive at the time of testing into asymptomatic or presymptomatic; imputation of missing data on clinical status at the time of testing into asymptomatic, presymptomatic or symptomatic; and imputation of the date of onset of symptoms for presymptomatic and symptomatic cases (Methods). Imputations were performed n = 100 times. Uncertainties (black bars) correspond to the 95% confidence intervals. Test positivity rates were computed for cases with complete information. Data for weeks 20–26 were consolidated in week 30. b, Breakdown of virologically confirmed cases with symptoms and complete information in the SI-DEP database by week of testing according to the declared onset of symptoms (left y axis; n = 5,514). The estimated time from onset to testing is also shown (right y axis; median and 95% confidence interval obtained from n = 100 imputations of the onset date). c, Weekly incidence of suspected cases of COVID-19 (median (dashed line), 95% confidence interval (shaded area) and 3-week moving average (solid line)), and percentage of individuals seeking healthcare (median and 95% confidence interval), estimated from the participatory surveillance system, COVIDnet.fr (average weekly n = 7,481). d, The number of suspected cases of COVID-19 in the participatory cohort who sought healthcare, and among those individuals, the number of individuals who received a prescription and performed a virological test when given the prescription. e, Estimated change in presence at workplace locations over time and by region based on Google location history data17. Region acronyms are listed in Table 1. f, Percentage of individuals avoiding physical contact with respect to lockdown, estimated from a large-scale survey conducted by Santé publique France18.
