Keep the numbers low

7 April 2020

Working from abroad, Mexican scientists are repeating the call to stay home and wash your hands. Members of the Científicos Mexicanos en el Extranjero (a state sponsored program for post-graduates working at foreign institutions) and the Laboratorio ConCiencia Social applied a model developed by Scots doctors W.O.Kermack and A.G.McKendrick in 1927 to analyze the path of the virus, using differential equations to detail how an infectious outbreak arises, its growth, when it reaches its maximum and how it later declines given biological and social parameters. The model was applied to the “real time” progress of the pandemic in five countries: China, Spain, Italy, the United States, and Mexico.

The purpose of the study is to measure the effectiveness of health control measures in the various countries. The conclusions seem to be that the Mexican response is showing positive results. The United States… less so.

“There is real-time information, there are different evolutions of this outbreak that can be distinguished by the curves observed in these measurements of infected people, and there is also information on the measures that governments around the world have implemented to try to control and mitigate the epidemic outbreak,” explained Dr. Rosa María Vargas, a specialist in applied mathematics of non-linear phenomena.

In the case of the country governed by Donald Trump, the analysis points out that 21 days after the outbreak began at the contagion rate, it has not decreased significantly because the control measures were applied late.

“One of the complications of the United States is that it is a very heterogeneous model, this model works well with outbreaks located in regions, so when we have a very large country, with different outbreaks, with different regional policies, what we are observing may be the result average of the country, which is not telling us if a mitigation measure located in the New York area or in the California area is working, “says the scientist.

The situation is different in Mexico, where a strategy was in place before the arrival of COVICD-19, which has mitigated the intensity of the outbreak. Although it is premature to measure the impact of those policies adopted y the Secretariat of Health, it can be expected that, assuming the citizens follow recommendations, the contact rate would be 0.319. If social distancing measures are maintained, the contagion rate would be even lower.

“In Mexico (the virus) came much later than in all other countries, we have data that the outbreak began to have a significant number only a short time ago, it is on March 19 with 118 infected. The containment measures began long before we even reached a number of one hundred people, we are well ahead of other countries, “said Mariana Vargas Magaña, researcher at the UNAM Institute of Physics.

Information from Forbes Mexico (“Científicos pronostican aplanamiento de curva de contagio en México“, Maria Fernanda Navarro, 7 April 2020)