The SARS-CoV-2 epidemic outbreak: a review of plausible scenarios of containment and mitigation for Mexico

Abstract

AbstractWe present here several variants of a mathematical model to explore three main issues related to SARS-CoV-2 spread in scenarios similar to those present in Mexico and elsewhere in Latin America. We explore the consequences for travel inside a given region, in this case Mexico, particularly focusing on airplane transportation but attempting to give a gross approximation to terrestrial movement since this is the main form of population movement across geographical areas in the country; then we proceed to study the effect of behavioral changes required to lower transmission by lowering the contact rate and infection probability and lastly, we explore the consequences of disease spread in a population subject to social isolation.These models are not suitable for predictive purposes although some rough predictions can be extracted from them. They are presented as a tool that can serve to explore plausible scenarios of spread and impact, effectiveness and consequences of contention and mitigation policies. Given the early stage at which the epidemic is at the date of writing in Mexico, we hope these ideas can be helpful for the understanding of the importance of isolation, social distancing and screening of the general population.Key findingsWe have estimated the parameters of the epidemic curve (growth rate, carrying capacity and dispersion) as well as a first estimate of the basic reproduction number for Mexico.We provide expected trends of epidemic outbreaks depending upon of the number of imported cases per day arriving to a large airport. We illustrate this trends with data from Mexico City airport.We provide expected trends of disease dispersal depending upon of the number of exported cases per day either by airplane or bus. We illustrate this trends with data from Mexico City.We evaluate the effect of behavioral change to reduce the contact rate and compare diverse scenarios that evaluate the timing of initial enforcement of behavior, time horizon in which to diminish the contact rate and the proportion of people under isolation.We evaluate the effect of social isolation by itself with respect to two main parameters: the starting time for the enforcement of control measures, and the learning time to achieve the desired contact rate reduction. We stress the importance of quick and direct actions to isolate and reduce contact rate simultaneously.