How 90% of French COVID cases evaded detection
In the weeks after France ended its first lockdown, nine residents with COVID-19 symptoms went undetected for every person confirmed to have the disease — despite a nationwide surveillance programme.
France reopened in May but adopted a strategy of testing, contact tracing, and case isolation to keep the coronavirus in check. To assess the results, Vittoria Colizza at the Pierre Louis Institute of Epidemiology and Public Health in Paris and her colleagues modelled COVID-19 transmission in France between mid-May and late June. They found that the national testing campaign missed some 90,000 people with COVID-19 who showed symptoms at a time when infections in the country were declining (G. Pullano et al. Nature https://doi.org/fn9k; 2020).
Source : https://www.nature.com/
