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

is the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10.1101/2020.03.28.20046276 doi: medRxiv preprint to achieve the contact rate reduction is either θ = 30 or θ = 90 days (differing for more than two months), the outbreaks are very similar which makes us postulate the existence of a threshold value θ * such that the peak incidence is reduced if θ < θ * . Larger learning times do not have an impact on the size of the epidemic. Figures 10-12 show examples of the behavior of the cumulative incidence (at 180 days after 10 infected are detected which we use as the indicator of initiation of the outbreak in this example) as a function of certain parameter values. Figure 10 shows that if T θ is closer to the time of detection of the first cases (in this example, when 10 infected people are detected), then the cumulative incidence can be reduced more efficiently and underlines the importance of reducing the effective contact rate quickly. In our example even when the reduction is only of 50%, we see that the final cumulative incidence decreases to low levels. This observation contrasts with what is shown in Figures 8 and 9 . We will discuss this in more detail later. On the other hand, Figure 10 (b) shows that even when the time it takes to get the contact rate reduction is large (θ = 90 days), we can still recover a large reduction in the final cumulative incidence provided we have a quick response to enforce reduced contacts and a large target reduction in the effective contact rate. Figure 11 shows that when T θ = 15 days, regardless of the time θ it takes to obtain the contact rate reduction, the final cumulative incidence is very low for large reductions in contact rates (q 1 small) or high for low reductions in contact rate (q 1 large).