Lockdown, relaxation, and ACME period in COVID-19: A study of disease dynamics in Hermosillo, Sonora, Mexico

Abstract

Lockdown and social distancing measures have been implemented for many countries to mitigate the impacts of the COVID-19 pandemic and prevent overwhelming of health services. However, success on this strategy depends not only on the timing of its implementation, but also on the relaxation measures adopted within each community. At the request of Sonoran Health Ministry, we developed a mathematical model to evaluate the impacts of the lockdown implemented in Hermosillo, Mexico. We compared this intervention with some hypothetical ones, varying the starting date and also the population proportion that is released, breaking the confinement. For this purpose, a Monte Carlo study was performed by considering three scenarios to define our baseline dynamics. Results showed that a hypothetical delay of two weeks, on the lockdown measures, would result in an early ACME around May 9 for hospitalization prevalence and an increase on cumulative deaths, 42 times higher by May 31, when compared to baseline. On the other hand, in respect of relaxation dynamics, the ACME levels depend on the proportion of people who gets back to daily activities or the individual behavior regarding prevention measures. It is important to stress that, according to information provided by health authorities, the ACME occurring time was closed to the one given by our model. Hence, we considered that our model resulted useful for the decision-making assessment, and that an extension of it can be used for the study of a potential second wave.

Modeling the COVID-19 pandemic: A primer and overview of mathematical epidemiology

“…To have a full picture of the effect of NPIs, it is necessary to formulate mechanistic mathematical models that explicitly take into account the impact induced by such sanitary measures. There are different approaches to incorporate NPIs into compartmental models, see, for example, [3,4,5,26,30,71,74,76,85,88,93,94]. Here, we formulate a compartmental mathematical model that explicitly incorporates: (i) isolation of infectious individuals and (ii) mitigation measures that reduce the number of contacts among the individuals in the population, namely, temporary cancellation of non-essential activities, lockdown, and social distancing.…”

Editorial

“…En otros Estados de la República también se realizaron estudios para evaluar el comportamiento de la propagación, así como del efecto de las medidas de distanciamiento social (Tocto-Erazo et al, 2020). Un grupo de la Universidad de Sonora realizó un estudio empleando el Método Montecarlo.…”