Group testing against Covid-19

National audienceIt is well-known that group testing is an efficient strategy to screen for thepresence of a virus. It consists of pooling n individual samples with a singletest using RT-PCR. If no individual in the group is infected, the group test isnegative. Thus, a single test may reveal this crucial information. We show howgroup testing can be optimised in three applications to multiply the power oftests against Covid-19: Estimating virus prevalence to measure the evolutionof the pandemic, bringing negative groups back to work to exit the currentlockdown, and testing for individual infectious status to treat sick people.For an infection level around 2%, group testing could multiply the power oftesting by a factor of 20. The implementation of this strategy in the short runrequires limited investments and could bypass the current immense shortageof testing capacity