Transmission Dynamics of COVID-19 and Impact on Public Health Policy

B Shayak; Mohit Manoj Sharma; Richard H Rand; Awadhesh Kumar Singh; Anoop Misra

We now discuss how our results can be used by the regional authorities of a city, district or county. We consider a region which is still approaching the peak and has implemented zero or partial social distancing measures. The biological parameters τ1, τ2 and μ1 will remain fixed, at the values used here or at values which the authorities obtain from their (likely more comprehensive) data sets. The initial value x (0) will be some fraction of the total population of the region (accounting for people who are resistant, people who are very seldom outdoors etc). Authorities can use their testing records to find approximate values of τ3, k3, k4 and μ2. Thereafter, the extant data for w (t) can be fitted to the model to determine a basic k0, and further refine the estimates of the other parameters. Given these, the authorities can now find the location of the expected peak in y, and impose a limited-duration lockdown centred round that peak. Figure 11 indicates that there is some margin of error here -the remaining percentage stays above 50 if the lockdown is imposed any time between the 34 th and 42 nd day. This is a considerably large window period which can account for inaccuracies in parameter estimation, disparities between model and reality etc. is the author/funder, who has granted medRxiv a license to display the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10.1101/2020.03. 29.20047035 doi: medRxiv preprint §4 CONCLUSIONS AND FUTURE DIRECTIONS In this work we have constructed a novel lumped-parameter mathematical model of COVID-19 which incorporates the effects of the latency period between transmissibility and symptomaticity as well as of the delay in testing on account of the limited testing facilities currently available. We have used this model to predict the effects of drastic but short-term social distancing measures on the spread of the disease. Our principal findings are that :