Explaining the Bomb-Like Dynamics of COVID-19 with Modeling and the Implications for Policy

Gary Lin; Alexandra T Strauss; Maxwell Pinz; Diego A Martinez; Katie K Tseng; Emily Schueller; Oliver Gatalo; Yupeng Yang; Simon A Levin; Eili Y Klein

If the proportion of individuals that are asymptomatically infected is actually higher than initially assumed, waiting for the emergence of observed cases to impose travel restrictions is not a productive policy, because (i) there are likely far more infected individuals than are observed, and (ii) due to the long dynamics of the incubation period, there is a large proportion of people who are already infected but not yet infectious. Evidence from China suggests that the observed data trail reported infections by about two weeks. In other words, despite dropping transmission dramatically between January 15 and January 25, the rate of newly confirmed cases did not begin to level off both country-wide and within each local city until two weeks later (Figure 4) .