SBMAC recognizes the interdisciplinarity, pioneering spirit and relevance of the research that has a researcher from the School as one of the authors
Researcher Claudio Jose Struchiner, from the School of Applied Mathematics of the Getulio Vargas Foundation (FGV EMAp), won the Johannes Kepler Prize 2024, granted by the Brazilian Society of Applied and Computational Mathematics (SBMAC).
The research, entitled "Optimized delay of the second Covid-19 vaccine dose reduces ICU admissions", used a mathematical model to determine the effectiveness of postponing the second dose of the vaccine and what would be the ideal delay interval between doses to maximize the initial benefit of immunization at a critical moment in the pandemic. Published in 2021 in the prestigious scientific journal Proceedings of the National Academy of Sciences (PNAS), the article also has as co-authors researchers Paulo Silva and Claudia Sagastizábal, from Unicamp, and Luis Gustavo Nonato and Tiago Pereira, from USP.
“We created a mathematical model that uses the hospitalization rate as a key metric to determine the best time to administer the second dose of the vaccine. It considers information about how the vaccine works, how much of it is available, and who needs it most. The model also predicts how many people may need to go to the hospital due to Covid-19 at different ages”, explains Luis Gustavo Nonato, from ICMC-USP.
"Mathematical language is essential to represent the mechanisms of action of each element of this system, such as social mobility, the immune response and the infectivity of the pathogenic agent", adds Claudio Struchiner, who has a PhD in Population Dynamics of Infectious Diseases from Harvard and is currently Vice-Director of FGV EMAp.
Claudio is a Full Professor at FGV EMAp | Photo: FGV EMAp
The study revealed that, depending on the vaccine's efficacy and mechanism of action, delaying the second dose could be an effective strategy to alleviate pressure on health systems.
“This relationship depended heavily on the strain of Covid-19 in circulation. At the beginning of the vaccination period, the predominant strain was more sensitive to the first dose, which justified postponing the second dose as much as possible to cover the majority of the population”, says Professor Paulo Silva, from IMECC-Unicamp.
According to the model, for vaccines that block infection with 50% efficacy after the first dose, the second dose can be delayed by up to 8 weeks. A similar delay is recommended for vaccines that are 70% effective in preventing hospitalizations. Furthermore, the modeling predicted that delaying the second dose by 12 weeks for a vaccine that blocks infection with 70% initial efficacy could reduce ICU admissions by up to 400 per million people over 200 days. The findings suggest that even with partial immunity, the optimized second-dose vaccine model leads to a massive reduction in ICU admissions and lockdowns, potentially saving lives and accelerating the return to normality. These results highlight the importance of adjusting vaccination strategies to maximize public health benefits in different epidemiological contexts.
Claudia Sagastizábal, from IMECC, highlights the versatility of the mathematical model developed, which was adapted to identify areas with the greatest demand for ICU beds in São Paulo and to define strategies for systematic testing for Covid-19. “We also collaborated with the state of Rio Grande do Sul to determine the ideal time to resume economic activities in several cities. The abstraction of mathematics is not always well understood by the lay public. But works like the one in the award-winning article can be appreciated by people other than specialists. I think this point is fundamental to disseminating the practice of multidisciplinary work in Brazil”, she highlights.
Since 2020, SBMAC has been offering the Kepler Prize to recognize national scientific production in Applied Mathematics. The 2024 winning work integrated expertise from several areas and was a pioneer at that time in providing crucial and accessible information for decision-makers.
Tiago Pereira, a professor at ICMC, is proud to receive an award that honors one of the founders of modern science. "Kepler was a great pioneer in data science, with applications of mathematics to astronomy. We are very happy to continue Kepler's tradition and apply mathematics to solve problems in our daily lives", he says happily.