Chilean and Mexican experts compare strategies for COVID-19

Chilean and Mexican experts compare strategies for COVID-19

The meeting was organized within the framework of the project “Mathematical modeling of epidemic processes, incorporating population structure, regional and risk groups”.

The Center for Mathematical Modeling (CMM) of the University of Chile and the Institute of Mathematics of the National Autonomous University of Mexico (UNAM) developed the seminar “Comparative experiences between Chile and Mexico in the management of the COVID-19 pandemic: Lessons learned and future challenges“.

The international meeting brought together government and health authorities, academics and researchers from both countries in the Rhine Room of the Hotel Plaza San Francisco in Santiago, Chile, who presented, debated and agreed on future strategies for decision-making, social determinants and gender perspectives based on mathematical modeling.

Chile and the pandemic

At the opening, the head of the Department of Epidemiology of the Chilean Ministry of Health, Christian Garcia, made “a recognition, first of all, to all the health officials who gave their best effort during the hardest period we had during the pandemic, which included nothing more and nothing less than 1,303 days of health alert (…) I would also like to highlight the role of the authorities who were faced with the greatest challenge in public health that we have had in our country. Decision-making is a complex process and in these emergency situations there is a high exposure and, of course, high pressure from different sectors of society”.

We have had to lament the death by COVID-19 of more than 57,000 people in our country, becoming the first cause of death in the years 2020 and 2021. The impact was so significant that it reduced life expectancy in men by 1.5 years and in women by 0.9. And the maternal mortality rate increased by 64%,” he explained.

Along these lines, García estimated that “60% of the new diseases are zoonotic diseases transmitted from animals. Of these, 72% originate in wildlife, such as SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome Coronavirus), or Ebola. More than half of these are caused by bacteria or rickettsiae, many of them resistant to antibiotics and other drugs. That is why it is necessary to be prepared to face these not so new challenges, which the pandemic has made even more evident”.

The Minsal authority specified the coordinated public-private actions developed by the previous and current administrations. “The pandemic leaves us with knowledge and molecular biology capabilities throughout the territory as we never had before, and we must incorporate them into our daily work and prepare to rapidly increase diagnostic capacity in the event of a new health emergency (…) Do not forget to learn, take the information to generate knowledge, learn from the experience to hopefully forge the wisdom that we will require for the next pandemic, which we do not know when it will occur, but we do know that it will occur. Some say it is for influenza in 2028, but let’s be calm, we will see,” he emphasized.

“The vast majority of potential pandemics are controlled at the source and few people know about them. That silent, low-profile work is what we need to strengthen and what we started in the Ministry -in the year 2022-, in conjunction with the CDC (Centers for Disease Control and Prevention) of the United States, to train in field epidemiology through the Field Epidemiology Training Program (FETP) for first-line responders and which already has more than 50 professionals trained in each and every one of the regions of our country“, he pointed out.

Christian Garcia also highlighted that “a few weeks ago the program was officially incorporated by the Training Programs in Epidemiology and Public Health Interventions Network (TEPHINET), the most important epidemiology and field epidemiology training network in the world”.

Mexico and the pandemic

The perspective of the North American country -which had more than 335 thousand deaths-, was presented by the head of Foreign Affairs of the Embassy of Mexico in Chile, Carlos Iván Mendoza, who said that “when making a comparison, we know that the handling of the pandemic by these two countries had great differences. To begin with, Mexico never closed the entry of people from abroad. I believe that both countries were quite successful in their respective approaches, although there were many losses.

After highlighting the role of health officials, the Aztec authority described the “invisible work” carried out by diplomatic personnel around the world. “We had a participation, first, in the repatriation processes of our compatriots who were suddenly prevented from returning to the country, which implied a quite complicated process of enabling special flights, negotiation with the countries, permits and the allocation of special resources for all this mobilization“, he pointed out.

In this regard, he remarked that “after the vaccine acquisition processes, some very complicated processes were revived regarding which countries could have the vaccines in the first instance and a whole series of debates, because it was a matter of resource allocation. The power of the nations was also seen which, unfortunately, is not symmetrical, but I believe that our respective countries made great efforts and were among the first, at least at the Latin American level, to have the vaccines. And obviously they were assigned free of charge to the population”.

Mendoza reflected that “as embassies, from our fields of action, the constant dialogue and mutual support between governments and institutions meant the crucial platform to respond to the global needs faced by the pandemic. In this case, the exchange of experiences, from the role of mathematical modeling, will allow us to think of future comprehensive public policies that consider the interdisciplinary perspective and seek cooperation between governments, educational and research centers and even civil society itself. United and coordinated, we will be better able to provide substantive support to our respective populations“.

The Chile-Mexico project

As a result of this global event, on September 1, 2023, the Center for Mathematical Modeling (CMM) of the University of Chile, the Center for Epidemiology and Health Policies (CEPS) of the Universidad del Desarrollo, the AM2V research group of the Universidad Técnica Federico Santa María, the Universidad de Aysén, the Institute of Mathematics and the Escuela Nacional de Estudios Superiores Unidad Juriquilla of the Universidad Nacional Autónoma de México (UNAM), and the Universidad de Sonora of Mexico, began the binational project “Mathematical modeling of epidemic processes incorporating population structure, regional and risk groups“.

This international initiative is financed by the Chile-Mexico Joint Cooperation Fund, signed on January 26, 2006, and managed by the Chilean Agency of International Cooperation for Development (AGCID) and the Mexican Agency of International Cooperation for Development (AMEXID), to promote the execution of programs, projects and/or bilateral and trilateral actions of cooperation for development.

Héctor Ramírez, director of the CMM, was in charge of presenting the project at the seminar and explained that “these were two or three very hard years, in which we faced an epidemiological phenomenon, the most serious in the last 100 years. The World Health Organization (WHO) reported in 2024 that more than 624 million people have been infected and more than 7 million have died (…) In academia we were not the most affected, but it was a very interesting moment of stress. On the one hand, it was a unique and different opportunity to bring our work closer to decision making and, on the other hand, it filled us with challenges, from logistical ones to work from home and how to organize our institution, to thematic ones, because there were many questions, such as: what priorities do we have, what doubts are we able to answer, or how do we find topics that we can address and are interesting for decision makers?

In this line, the professor explained that “the CMM together with the Universidad del Desarrollo and the Universidad Federico Santa María, we had been working for more than five years before the pandemic, of course with a much more academic approach, around the subject of economy and epidemiology, which was enhanced in the pandemic and more researchers from the Universidad de Aysén were incorporated, contributing to this multidisciplinary focus and also with a greater regional spectrum. We actively participated in the data sub-table (of the Government of Chile), all this challenge in making available the data generated for research and decision making. This was an initiative of the Ministry of Science when it was led by Professor Andrés Couve.”

“We also led and organized the line of predictive models of the Mesa Social COVID, organizing four workshops on mathematical modeling of the pandemic, which allowed us to orient ourselves to what we could respond to in a consensual manner for decision makers. This group was one of the first to produce freely available tracking and monitoring tools for some biological indicators, which were widely used until the end of the pandemic. There was also individual participation of many researchers, here I would like to mention the ICOVID group, because I had the pleasure of working (in that initiative)”, he added.

After describing the panorama during the pandemic, Héctor Ramírez clarified that “we feel that we are on the way out, a normality is noticeable thanks to the global vaccination effort, but the future threat of a high level biological event exists, it is there (…). ) With Mexico we had a relationship, through virtual seminars, and we realized that methodologically we are very similar and there were also certain common shortcomings in how we approached the pandemic, the effectiveness of vaccination and other differences with respect, for example, to social distancing measures that are worth studying in more depth”.

“Regarding vaccination we know that in the world there have been reported groups that have not been vaccinated in the last wave. It is well studied that this is due to two factors, on the one hand there are attitudes and behaviors of exhaustion and economic need, and on the other hand there are doubts due to ideological, religious and even political trust issues. With this in mind, we identified the Chile-Mexico Fund and began a project to develop mathematical models that incorporate social and behavioral determinants of people, thinking about future pandemics,” he added.

The binational instance officially began on September 23, 2023 and has a work term of 24 months. “We are very advanced with the comparative art study between Chile and Mexico, we are identifying factors and consequences relevant to the mathematical world of the focus. The idea is to build and do the subsequent studies of the models that come out there, learn them and transfer them to the agencies and institutions of both countries,” Ramirez sentenced.

The Ministry of Science makes its debut

After these presentations, the international seminar included two blocks of expert talks on “Comparative experiences with a focus on the support of science in decision making” and the “Impact of Social Determinants and Gender Perspectives in Epidemic Management”, and a round table on “Lessons learned and future challenges in decision making based on mathematical modeling”.

Andrés Couve, currently a tenured professor in the Department of Neuroscience at the Faculty of Medicine of the University of Chile, in 2018 took on the challenge as Chile’s first Minister of Science, Technology, Knowledge and Innovation, which began operating on October 1, 2019, a few months before COVID-19 detonated.

“The Ministry of Science reorganized the system for creating knowledge, training people and incorporating that knowledge into the productive world. This is what we call today the National System of Science, Technology, Knowledge and Innovation. In addition, for the first time, the coordination of science and technology in Chile was deconcentrated territorially. And it also found us with a much more mature ecosystem than 20 years ago. We have a significant number of universities, centers and companies that do research, and postgraduate training programs. And actors have appeared that function as enablers of this ecosystem, for example, the Armed Forces,” he said.

Things were done well here. It is not by chance that in Chile we have been prepared in immunology, in infectology, in data. We were prepared because we had invested for many years in a rich and diverse base of knowledge production (…) During the pandemic what we did was to have a single purpose. When you have a single purpose and that purpose is the common good, all actors capture value“, emphasized the former Secretary of State of Sebastián Piñera.

After listing the achievements of the portfolio, such as the speed of awarding research funds, the creation of a network of diagnostic and genomic surveillance laboratories for the early detection of variants of the virus, the national vaccine strategy thanks to the linking of national academics and foreign laboratories, the manufacture of high standard mechanical ventilators or the joint work with the Foreign Ministry and the Ministry of Health for inoculation campaigns, Andrés Couve emphasized that “the objective was really to open up the data to inform the public, to investigate and to make decisions“.

We have always worked with the conviction that free access to data is what has to happen in a democratic society: transparency, explainability, reproducibility and responsiveness. We ran out of problems once we opened the data to the public, because instead of calling the press they called us and corrected what was wrong and we applied what was right (…) The greatest advantage that data provides is when it is open, when everyone can contribute, when everyone can work, when everyone can criticize the data and not the lack of data”, added the doctor in cellular biology.

Finally, the former minister reflected that “I have not seen so far a transformation of the pandemic equivalent to what was, for example, the earthquake, where there was a complete reformulation of the public agencies in charge of emergencies. We have not done that, we have it pending and we have to do it because we do not know when it is going to arrive, but it is going to arrive and we have to be prepared for a future biological threat”.


The dean of the Faculty of Medicine of the Universidad de Concepción, Ana María Moraga, was a member of the External Advisory Committee of the Minsal during the pandemic and, together with experts from the Universidad de Chile and the Pontificia Universidad Católica de Chile, built the ICOVID platform.

“The dimensions of the analysis of indicators were the dynamics of contagion, testing, traceability and hospital capacity, because for the control of the pandemic we needed to know the dynamics of the risk of having the disease and the speed at which the pandemic began to evolve. We needed to know the capacity of the health system to face the pandemic, that is to say, the availability of beds at national level, the capacity to detect and manage new cases, the speed of testing and the speed of traceability“, he remarked.

He went on to say that “we built a traffic light. We thought it was more intuitive and easier to understand for the general population. Red, orange, yellow and green. We were fine in green and we were in crisis in red, and it worked for us (…) This becomes important when, for example, in the region of Coquimbo we could see the information for the region, for the province and for a health service, and notice that the information was different”.

Regarding the lessons learned, the surgeon and Master in Public Health listed: “the first is the multi and interdisciplinary work; second, the joint work of the academy plus the ministries increases credibility, but fundamentally multiplies the results; third, the regional, provincial and communal view for the construction of indicators, analysis and strategies to multiply results and adherence to the recommendations; fourth, to make the media health literate, because they are our allies; fifth, to incorporate technical experts from regions other than the Metropolitan Region multiplies the dissemination of information and the effects sought; fifth, incorporating technical experts from regions other than the Metropolitan Region multiplies the dissemination of information and the effects sought; sixth, time and resources are required from the universities to generate health information according to the needs of the State; and seventh, joint work between the public and private networks is possible and very positive for everyone”.

Mexican predictions

Jorge Velasco, a senior researcher at UNAM’s Institute of Mathematics and member of the Mexican Academy of Sciences, was the leader of several modeling research teams on COVID 19 in Mexico. “We were involved in providing information to the Ministry of Health, the General Directorate of Epidemiology, the Ministry of Innovation and Technology of Mexico City, the Ministry of Health of the State of Queretaro and the Ministry of Education, where we helped with the return to school. We interacted with different instances that were hungry for information analysis that would allow them to form criteria to make decisions,” he said.

The professor emphasized that “one of the most interesting areas of research strictly in mathematical modeling of population processes, particularly epidemics, is the effect of human behavior. How difficult it is to model human behavior! It is our challenge. For example, if we want to make a prediction of COVID and I am told ‘the risk of going out and getting infected is 90%’, I don’t go out. If many people don’t go out, contagion will not occur and they will say the model is wrong”.

In Mexico, prediction was prioritized over scenario generation, particularly at the beginning of the pandemic. ‘I want to know when is the maximum prevalence,’ is a good faith question but a bit tricky, because if there is a maximum that means it is going to go down. But if they ask me to predict the maximum and I tell them that it will happen between May 6 and 8 -when it really happened until July-, and that the end of the epidemic was going to be June 26, 2020 with 90% confidence, well, a real mess was created and confidence in the predictions, which is such a useful tool, began to be lost“, he described.

In this context, the biologist and doctor in mathematics remarked that “there are very particular causes. The underreporting was very large, there was a very low application of diagnostic tests, a sentinel model was used which is designed for known viruses where we can estimate the total prevalence of an area -in COVID it was absolutely impossible to do that-, and emphasis was placed on curve fitting (…) The fact is that there was an official model that was calibrated with the epidemic curves of Wuhan, Spain and Italy and from there those dates came out”.

“We use a model called COVID Testing, which was developed by Johns Hopkins Medicine, and it is very interesting because it estimates only one parameter, which is the reproductive number. All the others, which are many, are not really parameters, but are obtained from probability distributions. For example, the probability that someone infected on any given day will end up in the ICU (…) The explanatory capacity of the phenomenon is greatly increased because you don’t have all that uncertainty attached to it,” he explained.

Velasco also pointed out that “the modeler’s dilemma is really an ethical dilemma: when is modeling necessary in an epidemiological process, when is it appropriate or when is it counterproductive? An example of counterproductive is trying to predict a maximum, but at the time of the hour (sic) we have to have a way to do it (…) I am promoting, together with other colleagues, mathematical modeling centers specialized in epidemiology, because we need models for operational purposes, not just academic ones, and to offer a unified voice for decision makers“.

Genomics and data

Alejandro Maass, principal investigator of the CMM, who was a member of the COVID-19 Social Roundtable at the Data Sub-table, then presented his work. He explained that “what we did in my laboratory was to support genome sequencing and to differentiate PCR markers between traditional viruses or epidemics and less traditional epidemics. On March 3, COVID started (in Chile) and on March 30 we had a data table. More than 70 products were generated and the Ministry of Science said ‘I am going to be responsible in time’, almost without personnel”.

The also academic of the Department of Mathematical Engineering of the Universidad de Chile said that “we invented the maximum exponent profile. If you calculate a dynamic series, you can think that there was a differential equation behind it and that this differential equation – which I don’t know – at each point had a certain exponent of explosion. So, we gave smaller intervals and started to see if that indeed had some behavior. And we started to find that the numbers here were 0.4, 0.5, 1″.

The interesting thing in Chile is that you see possibly the only country that went negative. That is, at the beginning it was so severe the intervention in the pandemic that it took it to negative. We didn’t see any time series that did that. That is, Chile managed to infinitesimally control the pandemic. After that, the variants began to arrive and when Omicron arrived, obviously this grew”, emphasized the doctor in Pure Mathematics.

In closing, the former director of the CMM emphasized that “the vaccination campaigns showed a tremendous success, especially with the second vaccination. Possibly the number of admissions to the ICU, which dropped by 70%, has to do only with the second vaccination. It is interesting because the first two were vaccines from China and with two vaccines Chile avoided much of what happened in the world and we are an underdeveloped country”.

Social determinants of health

The second block was initiated by María Isabel Matute, professor and researcher at the Center for Epidemiology and Health Policies of the Universidad del Desarrollo, who was in charge of the original project and of updating the Regional Health Diagnoses with a focus on Social Determinants for the Chilean Ministry of Health.

In her presentation, Dr. Matute addressed the concept of “inequity in health”, stating that “inequity implies a value judgment, it is something that is not being fair. In addition to being unfair, inequities are systematic and have the characteristic that they are produced and reproduced socially. The bottom line is that we ask ourselves which of these residents of these neighborhoods are going to have better health. And that is where the concept of social determinants of health (SDH) comes in, which look at the conditions in which people live, grow, work and develop. They have a cumulative component throughout the life course and are determinants that interact with each other, sometimes one can enhance the effect of another determinant”.

“There are different models that seek to explain the approach to social determinants; we will be guided by the WHO model, where there are the intermediate determinants -which are very similar to risk factors and sometimes the direct causes of health conditions-, the structural determinants -which are also known as the causes of the causes, which are behind the intermediate factors-, and the socio-political context“, he explained.

Along these lines, Matute pointed out that “in the social structure we have a hierarchy that will determine our assets, prestige and power. This affects our behavior and conditions for managing health risks. Therefore, it generates inequities in health outcomes and also social consequences (…) This model emphasizes much more the social hierarchies in the production of health inequities and also the importance of the context. It establishes that the social hierarchy or the social position of people will affect health based on their relationship with these intermediate determinants”.

“In the end, the most vulnerable groups or those with a lower socioeconomic level will have a greater exposure and, therefore, will have an effect on their health. A person who has a health problem will face it and will have very different consequences according to his or her position in the social hierarchy and the resources he or she has to manage it,” said the sociologist and Master in Public Health.

The expert also exemplified these definitions with cases of mortality in Chiapas in Mexico and the Metropolitan region of Chile, and then emphasized the factors that increased contagion. “The evidence told us that overcrowding, lack of electricity and Internet, living in large cities, difficulty in accessing stores, pharmacies or services, and the impossibility of working, were factors that increased the risk and severity or deaths associated with COVID,” she said.

Matute added that “psychosocial factors were also present, such as stress, social isolation or uncertainty. Within the behavioral aspect, there is evidence in relation to smoking in that it aggravated the outcome. There are biological factors, the best known being obesity. And the health system, a social determinant that can cushion the effects of structural determinants”.

Regarding the latter, he stated that “here we have the issue of wealth, assets and prestige. Structural determinants affect intermediate determinants and therefore have repercussions on the results of health inequities“.

“Education has an effect, for example, on health literacy, on the possibility of leaving or not leaving the house, on the experience one has in terms of digital means to transfer education to the home, and so on. Occupation can be a direct determinant in terms of risks and exposure, but also an indirect determinant when you look at job stress, independence, job insecurity, i.e. things that make containment measures more difficult and also increase inflammatory possibilities in the body. Ethnic groups, because there is an issue of restriction of autonomy in decisions for women and this idea that men do not go to the doctor’s office, for example”, she specified.

The researcher concluded that “the pandemic not only maintained, but also deepened social inequalities at the level of social determinants. We not only see inequities at the level of health outcomes as a result of social determinants, but we also see that the pandemic had an impact on social determinants“.

Gender perspectives on epidemics

Continuing along the line of social determinants, the researcher of the Center for Mathematical Modeling of the University of Chile, Gloria Henríquez, focused her analysis on “the state of the art regarding gender issues in research work related to mathematical modeling and epidemics“. She emphasized that “for the Chile-Mexico Cooperation Fund, the gender issue is relevant. That is why we were given the mission to address it in research and also as a structure and work team, this to ensure equity not only in the analysis, but also in how we distribute our work”.

“We started by defining our search terms where we have mathematical modeling, health and epidemiology of social determinants. What interventions were done in both countries or in the different countries. There we selected the scientific articles with high, medium and low relevance that responded to the search terms and mainly those related to gender,” described the first woman engineer and physician of the Chilean College of Engineers.

“We selected 60 (research papers) for the project and nine for the gender review. What criteria were used to give high, medium or low relevance? For the high relevance review: having good databases, good gender disaggregated data, and treating the gender review fairly. For medium relevance: the exclusion criterion was to base the interpretation on results from aspects other than gender. For example, gender was mentioned in the text, but in reality the emphasis for the analysis was on age or other aspects. And for low relevance: the development of the topic was insufficient, unclear or the results were not adequately based on gender,” she said.

Regarding the results, the also Master in Clinical Epidemiology and PhD in Engineering Sciences said that “something important is that in the works reviewed most of them use gender and sex as synonyms, and many times it is difficult for the reader to discriminate in what sense they are using them. Therefore, here I did not base it on the differences because it is not clear. For disease relationship, from symptom onset to diagnosis, it was seen that disease severity, mortality and excess mortality, need for ICU, ICU stay, and time to diagnosis was higher in people of male gender. So watch out for the men.”

“In terms of perception and behavior, there were studies associated with risk perception of the disease, feelings about the pandemic, acceptance of the vaccine and use of public transportation. It is super diverse, they do not converge in something in particular, but they were studied or appear in different studies. Vaccine acceptance in general tended to be higher in the female gender. The use of public transport was mentioned as something important in terms of contagion, because they realized that women use public transport more than men, for example, to go to work,” she said.

Presenting a study from Belgium, Henríquez pointed out that “women dropped out of school more than men, more women were fired from their jobs or had to resign for care work, and gender violence increased”. Meanwhile, a study of 1,012 patients at the Hospital de la Florida in Chile, where the distribution by gender was 43% male and 56% female, showed that “in deaths versus non-deceases, 68% of men died compared to women. Also, the severity of the disease in men was greater than in women. This is relevant because all the studies that addressed this issue repeated the same pattern – with different figures – but it was always higher in men than in women”.

Referring to a Mexican study, the CMM researcher said that “there were 12,000 individuals who responded to a survey and its main conclusion is the heterogeneity in the perception of risk manifested by these different parameters: age, gender and expression of feelings. This last behavior was similar in both genders or sex, it increases as the perception of risk increases and this leads to a lower level of boredom. In contrast, there was a different behavior in terms of feelings of alarm, fear, confusion and depression, which was higher in females than in males.”

Live broadcast:

Center for Mathematical Modeling

The CMM is today the most active scientific research institution in mathematical modeling in Latin America. It is a center of excellence of the National Agency for Research and Development (ANID) of Chile, integrated by eight partner universities and located at the Faculty of Physical and Mathematical Sciences of the University of Chile. It is also the International Research Laboratory (IRL) #2807 of the National Centre for Scientific Research (CNRS).

Its mission is to create mathematics in response to problems in other sciences, industry and public policy. It seeks to develop science with the highest standards, excellence and rigor in areas such as data science, climate and biodiversity, education, resource management, mining and digital health.

By Alonso Farías Ponce, journalist at the Center for Mathematical Modeling.

Posted on May 20, 2024 in News