A simple method to quantify country-specific effects of COVID-19 containment measures

Morten Gram Pedersen; Matteo Meneghini

In our setting, to fit the data on identified SARS-nCov2 positive cases, a SIQR [1] is appropriate. In this model, infected individuals may be isolated, entering the "quarantined" subpopulation Q, so that these individuals no longer transmit the disease. Since positive cases are put in isolation (in hospitals or at home) immediately, the revealed data of active cases thus corresponds to the number of individuals in state Q. It would not be correct to confront the infectious subpopulation of a SIR/SEIR (susceptible -infectious -[exposed] -recovered) model with the recorded data, since it is unknown how many infectious but undetected individuals are circulating in the population. As will be clear in the following, besides being conceptually clearer, the explicit quantification of the quarantined individuals will allow us to provide estimates of the infectious cases at the very beginning of the epidemic outbreak as well as of the current number of undetected infectious individuals.