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

For our simulations, we employ flight data for February 2020, terrestrial data for January 2018/2019 and take February 21st as the initial date of the arrival of the first cases. This estimate is plausible since the first cases in Mexico were reported on February 28th but given that the incubation period is of 6 days they likely arrived to Mexico City on February 21st or 22nd. We also set the population size of the Greater Metropolitan Area of Mexico City at 25 210 748 inhabitants. To estimate the inbound/outbound international travelers migration rates, we take into account all flights that arrive/leave Mexico City [16] . Thus, the daily average number of international arrival and departure air travelers are L im = 22, 519 and L mi = 21, 838, respectively. See Appendix G for the procedure followed to give this estimates. To estimate the inbound/outbound national travelers migration rates we integrate air and terrestrial transportation. For national flights we arbitrarily select the thirteen more important destinations from Mexico City, i.e., those who have more passengers inbound leaving from Mexico City. On the other hand, to estimate the number of terrestrial passengers, we use data from the above mentioned four main bus terminals of Mexico City. Therefore, we calculate the averages per day of national passengers in both kinds of transport (airplane and bus). Thus L sm = 141, 664 and L ms = 141, 425 except during the Holy Week (for more details see Appendix G). For the 2020 Holy Week (April 4th to April 12th), we proceed to increase previous estimates by 25% which is a rough and conservative approximation based on data from the Secretariat of Tourism [17] . Therefore L sm = 177, 080 and L ms = 176, 781 during this period and also the information available on the main bus terminals of Mexico City (for further details see Appendix G). Finally, the incubation and the infectious period are set to γ = 1/6 and η = 1/10 per day, respectively. Also, since we do not have data on the air passenger percentage that arrives in the latent or asymptomatic stage, we propose as a plausible valueq = 0.5 as a null hypothesis from which to start our analysis.