Modeling Exit Strategies from COVID-19 Lockdown with a Focus on Antibody Tests

Reinhard German; Anatoli Djanatliev; Lisa Maile; Peter Bazan; Holger Hackstein

Testing both for COVID-19 and for antibodies (ABs) will be important for an exit of the lockdown. For the time being we restrict ourselves to AB tests. Every person can be tested (in principle possible in all states, but testing would not be meaningful in state symptomatic), with either positive or negative outcome. We assume that persons with ABs are immune and will keep that property indefinitely (could be relaxed later). Therefore, positive ones, regardless in which state besides symptomatic, can change their social status from reduced to normal. We consider the sensitivity (by default 95%) of the test, leading to probabilities for true positives and false negatives (negative ones have ABs but would stay in reduced although not necessary). We assume also a high specifity and ignore false positives (positive ones without ABs would get normal but can still be infected), because this number is expected to be small. Test capacity is an important restriction and will be adjusted in the experiments, test duration is assumed to be one day.