A Multistage Time-Delay Control Model for COVID-19 Transmission

With the transmission of COVID-19 epidemic at home and abroad, this paper considers spread process in China, improves classic SEIR model, establishes a multistage time-delay control model (MTCM) for transmission. The MTCM divides into three periods: outbreak period, period steady period. classical improved SEQIR ? correspond to periods. was adopted yielded results that were consistent with observed early propagation In adding isolation measures time delay adjusting rates better simulation effect. focus consideration is number new patients, population movement (in-migration out-migration population) patient classification (symptomatic asymptomatic patients). MCTM used simulation, comparison revealed simulated data (improved model) actual are similar policy effective. New infections, flow patients symptomatic or symptoms more characteristics. multi-stage provides theoretical methods good prevention future formulation.