To procrastinate or not to procrastinate: the optimal timing of containing the global COVID-19 pandemic spread

As global public health is under threat by the 2019-nCoV, an urgent question to ask is what the optimal strategy of epidemic prevention and control (P&C) measures would be, especially in terms of the timing of enforcing aggressive policy response so as to maximise health efficacy and to contain pandemic spread. Here, we developed a logistic probability function configured SEIR model to analyse the COVID-19 outbreak and estimate its transmission pattern under different “anticipate- or delay-to-activate” policy response scenarios in containing the pandemic. We wound that the potential positive effects of stringent P&C measures would be cancelled out in case of significantly delayed action, whereas a partially procastinatory wait-and-see control policy may still be able to contribute to containing the degree of epidemic spread although its effectiveness may be significantly compromised compared to a scenario of early intervention coupled with stringent P&C measures. A laissez faire policy adopted by the government and health authority to tackling the uncertainly of COVID19-type pandemic development during the early stage of the outbreak turns out to be a very bad strategy from optimal control perspective, as significant damages would be produced in that case. Authors Jun Li and Yimin Zhou contributed equally to this work.