Cuban mathematician Lizet Sánchez Valdés won the Sofía Kovalévskaya Mathematics and Computing Award

July 12, 2022

In the whirlwind of her adolescent mind, the faces of Physics, Chemistry, Medicine, and Mathematics gazed at each other. There, on equal footing, they competed for her attention.

Since childhood, Lizet Sánchez Valdés has lived in a family environment where passion and dedication to the latter science have prevailed. But which one to study if she liked them all?

One day her mother sat down with her and advised her to study Mathematics; "this career applies to everything, you can do anything in life." That suggestion gave her something to think about and defined her path. "In my life I have done Mathematics applied to sociology, epidemiology, and other fields. The motivation came from there."

It is true that few women decide to dedicate themselves to the study of this basic science, and beyond that, there is a perception that it is a career more for men. But, along with Lizet, more girls graduated. Today at the Center for Molecular Immunology (CIM), where she works, there are five other mathematicians, and at the University of Havana several colleagues teach this science.

The reality around Lizet is that. She affirms that women can, just like men, reach this discipline and shares how her beginnings were.

"I studied in the Soviet Union for three years, then returned to finish my degree at the University of Havana. First I worked as a practice student at the National Center for Scientific Research in applications of Mathematics to Neuroscience. Later, in my fifth year, I became involved with the Pedro Kourí Institute of Tropical Medicine (IPK), applying this subject to epidemiology."

When the dengue epidemic in Santiago de Cuba occurred in the late nineties of the twentieth century, Lizet worked alongside her colleagues on a Cuban strategy for community empowerment to prevent this disease from the perspective of its key actors.

"A group was created to work on social participation in dengue prevention. I initially entered as a mathematician, then as an epidemiologist. There I incorporated myself into Social Sciences or Social Epidemiology with the mathematics component, where in the evaluation of interventions, data analysis is seen. All of this led me to my doctorate, but at the beginning what we did were experiment designs in laboratories, sampling in communities for surveys, and with social science practices we focused on finding indicators for decision-making."

In 2000 I again participated in dengue prevention. I remember that in command posts, to track the evolution of the disease, we worked to provide Fidel with concrete data.

"He asked for information that we had to analyze and we spent the night doing it. I was already a mother, with my two young daughters. Back then my coworkers from the command post would come to my house. My daughters were cared for by some of them while I prepared epidemic reports; that's when I did modeling and daily analysis of dengue data. All of this to evaluate actions and see where they were being executed."

With the arrival of 2020, for Cubans, as for most of the planet's inhabitants, a time of fear and uncertainty began with the appearance of the first COVID-19 patients. From that moment, and even a bit before, Cuba developed a strategy to protect the health of its citizens while beginning the process of creating its own vaccine candidates.

Lizet was one of the scientists who was part of the group of experts that has advised the government in the context of the pandemic.

In this scenario, the Mathematical modeling group addressed the differential equations of epidemic curve behavior, while the Doctor of Science focused her work on the statistical aspect, data analysis, evaluation of clinical protocol interventions, demonstrating which indicator makes the difference and how the changes and impacts of the actions that the Cuban government has been executing are being seen.

For the senior researcher at CIM there are no schedules or moments of rest. She also rarely gives interviews about herself. She is shy, but brave. Her love for science was the trigger for this dialogue that has led us to know her world.

Since graduating in the turbulent year of 1993, she has been involved in different projects for healthy communities, an initiative of the Pan American Health Organization that emerged at that time.

"I was part of a project directed by Professor Agustín Lage in Yaguajay, Sancti Spíritus. Several specialists from institutions in the capital came together to work on it. That was the first professional challenge I faced. I joined as a sampler; that is, they needed a mathematician to help them with initial surveys in order to do successive evaluations. I had never done sampling before. During my degree I had not received anything related to that area of study.

"The idea of population representativeness in the sample was another challenge for me, because, moreover, when you arrive at the place you realize the diversity that exists in the population; so how do you make a representative sample. It turned out very nice, because it was the first time I had the opportunity to work with a multidisciplinary group where mathematics, demography, and epidemiology were important. I saw the approach to a problem from a social, public health, and multidisciplinary point of view," recalls the biostatistics expert.

For a time, the senior researcher worked at the Santiago de las Vegas sanatorium, conducting evaluations of counseling services, among other activities. But in that setting what was difficult was, from a personal point of view, the life stories she heard from people suffering from the disease.

At that center she had the opportunity to coordinate with a sociologist a community project in Buena Vista that sought social acceptance of patients. According to Lizet, there was rejection and misunderstanding among neighborhood residents about the disease. Numerous workshops were held there to work on eliminating stigmas linked to machismo.

Her vocation then became social. How to improve the integration of these people in communities? Another challenge imposed itself on Lizet's life. After several working sessions in the workshops, the researcher's satisfaction was to hear from the people themselves accept themselves as seropositive. And the group grew, to the point of having to change to a larger space. Her greatest joy was having been useful.

"Knowing how to speak to different audiences"

What are the ways and means of translating scientific information so that it can be represented and useful for decision-making? Work experience has allowed Lizet to find ways to do it.

"Professionals in my field are accustomed to very abstract language and we want the method or model most interesting from a mathematical, theoretical point of view, but what is effective in practice are sometimes very simple things, which you can express with a graph, with a percentage; but you have to find that data and the challenge is there: what to extract from a volume of information and how to represent it so that it is not filed away and can be used. It is knowing how to speak to different audiences."

The scientist, he warns, has to know how to write science both for a publication in their field and for a report. "I learned it in the epidemics, but it also served me in biotechnology. Someone produces a vaccine, a drug. Then you present it to the Ministry of Public Health telling it the conditions it meets for its use and insertion into the basic medicines list. That is an example of the use of statistics as a tool for evaluation. In these times, what we have learned is how to speak to the population."

Precisely, she who is also a member of the Scientific Committee of the Medic Review magazine for the Cuban side, comments on the visibility that COVID-19 has had in the media and the challenge of knowing how to communicate to the population.

"There is an accumulation of information, from which we must classify its validity; that is, analyze that the data presented is valid. We do reviews of international literature and help classify. The other thing is to communicate. How do we communicate to the population so that it understands the message?"

A different space

Lizet is a simple, affable, and cheerful woman. She is not the stereotypical prototype of person sometimes associated with her profession, one who only has time to research. The way she speaks of her parents, husband, and daughters shows how family-oriented she is. And it also highlights her passion for nature, so much so that on her apartment balcony she cares for more than 20 types of plants.

Lizet was in a speleology group in the caves of Santo Tomás. If there is something she regrets about the current pandemic, it is that it took away her chance to go on excursions to places with these characteristics. She loves to travel throughout Cuba and get to know Cuban nature with her family.

"My family is everything. My parents were the ones who got me into this mathematics madness. My dad, besides being a mathematician, loves history. There is a mix between what I do and what is in the house, but no one talks about this subject there; it is time to share at home," she says emotionally.

Her passion for science resembles thirst. Her constant drive for improvement, to research, to find possible solutions to problems is evident. For her there are no obstacles. She confesses to being in a moment of scientific maturity, even though she is starting many new projects.

"I have a degree in Mathematics, a master's in Epidemiology, a Doctorate in Health Sciences, and I am a popular educator, but I have not done my doctorate in Mathematics, specifically in Statistics. I am enrolled in Belgium in a joint doctorate. But for that you must make methodological and theoretical innovations to this basic science. I am trying to transform and incorporate into the discipline the methods that have come from practice.

"I want to do my second doctorate uniting the teachings and what I have learned in infectious diseases and chronic non-communicable diseases. COVID-19 has given me that opportunity, because it is an infectious disease that is aggravated or is heavily influenced by chronic non-communicable diseases: hypertension, diabetes, and lung diseases, to name a few examples."

For the original and creative use of mathematical models to solve problems demanded by society, and for her contributions to teaching, Dr. Lizet Sánchez Valdés was awarded, in the Research category, the Sofía Kovalévskaya Mathematics and Computing Award, granted by the Cuban Society of Mathematics and Computing in 2021.

The biostatistics expert received this recognition for her research results, fundamentally in the development of medicines for the treatment of lung cancer and COVID-19.

"In 2012 I started working at CIM. At that time I was almost finishing phase three of the vaccine against lung cancer Cimavax and it was going to be used in practice. I joined as a mathematician, designing the intervention and the steps to carry it out. Also, as an epidemiologist, I would contribute to taking an innovation into practice.

"The Mathematics techniques that existed for analyzing that information fell short of what we needed. There we worked on novel methods to be able to address the problem of survival and long-term survival.

"That experience is very nice, because it made me make innovations from a mathematical point of view in the methods. I am passionate about that subject. In the exchange with the clinical laboratory team we do the analyses and implement methods to find what the biomarkers are and be able to differentiate patients. The practical problem takes you back to Mathematics, you see the methodological limitation and you start to develop a new method."

Time is not a rival for an enthusiast of basic science, nor would there be limits to this interview if we deposited in it all the experiences and scientific results of Dr. Lizet Sánchez Valdés, a woman who walks through mathematics without fear.