High impact epidemics constitute one of the largest threats humanity is facing in the 21st century. In the absence of pharmaceutical interventions, physical distancing together with testing, contact tracing and quarantining are crucial in slowing down epidemic dynamics. Yet, here we show that if testing capacities are limited, containment may fail dramatically because such combined countermeasures drastically change the rules of the epidemic transition: Instead of continuous, the response to countermeasures becomes discontinuous. Rather than following the conventional exponential growth, the outbreak that is initially strongly suppressed eventually accelerates and scales faster than exponential during an explosive growth period. As a consequence, containment measures either suffice to stop the outbreak at low total case numbers or fail catastrophically if marginally too weak, thus implying large uncertainties in reliably estimating overall epidemic dynamics, both during initial phases and during second wave scenarios.
The authors thank Malte Schröder for valuable discussions and creating the scale-free network topologies. B.H. thanks Mukund Vasudevan for helpful discussion. The research by M.T. was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany´s Excellence Strategy–EXC-2068–390729961–Cluster of Excellence Physics of Life of TU Dresden.
Scarselli D, Budanur NB, Timme M, Hof B. Discontinuous epidemic transition due to limited testing. Nature Communications. 2021;12(1). doi:10.1038/s41467-021-22725-9
Scarselli, D., Budanur, N. B., Timme, M., & Hof, B. (2021). Discontinuous epidemic transition due to limited testing. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-021-22725-9
Scarselli, Davide, Nazmi B Budanur, Marc Timme, and Björn Hof. “Discontinuous Epidemic Transition Due to Limited Testing.” Nature Communications. Springer Nature, 2021. https://doi.org/10.1038/s41467-021-22725-9.
D. Scarselli, N. B. Budanur, M. Timme, and B. Hof, “Discontinuous epidemic transition due to limited testing,” Nature Communications, vol. 12, no. 1. Springer Nature, 2021.
Scarselli D, Budanur NB, Timme M, Hof B. 2021. Discontinuous epidemic transition due to limited testing. Nature Communications. 12(1), 2586.
Scarselli, Davide, et al. “Discontinuous Epidemic Transition Due to Limited Testing.” Nature Communications, vol. 12, no. 1, 2586, Springer Nature, 2021, doi:10.1038/s41467-021-22725-9.
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