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

Manuel Adrian Acuna-Zegarra; Andreu Comas-Garcia; Esteban Hernandez-Vargas; Mario Santana-Cibrian; Jorge X. Velasco-Hernandez

As the main objective in this section is to study the consequences of disease importation to a large Latin American city, we assume first that a proportion of the international air passengers arrive as disease carriers. We define ρ t to be the proportion of international air passengers at time t who cannot transmit the disease, e.g., if ρ t = 0.75 then 25% of the international air passengers are infectious. Of these carriers, a proportionq arrive as exposed not yet infectious individuals and 1 −q arrive as asymptomatic infectious individuals. L ms and L sm are functions of time describing travelers either arriving to Mexico City airport of leaving Mexico City airport. These rates are time dependent since we eventually take into account the increase on the number of national travelers during holiday periods, specifically Holy Week in Mexico. For the analysis we perform a normalization in order to work with proportions and not absolute numbers of individuals (see (6) , Appendix C). One of the goals of this manuscript is to study the arrival of COVID19 to Mexico City and its plausible patterns of propagation. The timeline of our study is half a year. To estimate the daily average number of national and international inbound/outbound air and road travelers, respectively we employ information from the Secretariat of Communications and Transportation (SCT) [16] and the General Directorate for Tourism Competitiveness of Mexico City [17] . The timeline is set to include Holy Week, a short holiday which normally presents an increase of arrival/departure flights to/from Mexico City. On the other hand, the main transport means of the Mexican population is by far terrestrial by bus. Unfortunately, we only have data on the number of bus passengers outbound from Mexico City, reported by the large bus terminals Norte, Sur, Poniente and Oriente. We will assume that on average the number of bus passengers that arrive to Mexico City is greater than those that leave.