Change points in the spread of COVID-19 question the effectiveness of interventions in Germany
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This study attempts to assess the effectiveness of nonpharmaceutical interventions towards SARS-CoV-2 infections in Germany. Using dates of infection estimated from official case data, exponential growth models for infections and reproduction numbers were estimated and investigated with respect to change points. Clear evidence is found of a decline of infections at the beginning of March, which can be attributed to relatively small interventions and voluntary behavioral changes. The effects of later interventions remain unclear. Liberalizations of measures did not induce a re-increase of infections. These results contradict previous studies on the German case. The study also exhibits three methodological challenges with respect to assessing of interventions: a) the estimation of true infection dates, b) the usage of several indicators and c) the influence of test volume. In conclusion, the effectiveness of most German interventions remains questionable.
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