Research on optimizing second dose of COVID-19 vaccine wins 2024 Johannes Kepler Prize

Claudio Jose Struchiner, a researcher and vice dean of Fundação Getulio Vargas’ School of Applied Mathematics (FGV EMAp), won the 2024 Johannes Kepler Prize, bestowed by the Brazilian Society of Applied and Computational Mathematics (SBMAC).

The winning paper, titled “Optimized delay of the second COVID-19 vaccine dose reduces ICU admissions,” used a mathematical model to determine the effectiveness of delaying the second dose of a COVID-19 vaccine and what would be the ideal interval between doses to maximize the initial benefit of immunization at a critical time in the pandemic. Published in 2021 in the prestigious scientific journal Proceedings of the National Academy of Sciences (PNAS), the article was co-written with researchers Paulo Silva and Claudia Sagastizábal of Campinas State University, as well as Luis Gustavo Nonato and Tiago Pereira of the University of Sao Paulo.

“We created a mathematical model that uses the hospitalization rate as a key metric to determine the best time to administer a second vaccine dose. 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 of different ages may need to go to hospital due to COVID-19,” explains Luis Gustavo Nonato of the University of Sao Paulo’s Institute of Mathematical and Computer Sciences.

“Mathematical language is fundamental to represent the mechanisms of action of each element of this system, such as social mobility, immune response and the infectiousness of the pathological agent,” adds Claudio Struchiner, who has a doctorate in population dynamics of infectious diseases from Harvard and is currently the vice dean of FGV’s School of Applied Mathematics.

The study revealed that, depending on the vaccine’s efficacy and mechanism of action, postponing the second dose could be an effective strategy for relieving pressure on health systems.

“This relationship depended heavily on the COVID-19 strain in circulation. At the beginning of the vaccination period, the predominant strain was more sensitive to the first dose, which justified delaying the second dose as much as possible in order to cover the majority of the population,” says Professor Paulo Silva of Campinas State University’s Institute of Mathematics, Statistics and Computer Science.

According to the model, for vaccines that block infection with a 50% efficacy rate after the first dose, the second dose can be delayed for up to eight weeks. A similar delay is recommended for vaccines that are 70% effective in preventing hospitalizations. In addition, the modeling work predicted that by delaying the second dose by 12 weeks for a vaccine that blocks infection with 70% initial efficacy, ICU admissions could be reduced by up to 400 per million people over 200 days. The findings suggest that, even with partial immunity, the optimized model for the second dose of the vaccine promotes a significant reduction in the number of ICU admissions and a reduction in lockdowns, potentially saving lives and speeding up the return to normality. These results highlight the importance of adjusting vaccination strategies to maximize public health benefits in different epidemiological contexts.

Claudia Sagastizábal of Campinas State University’s Institute of Mathematics, Statistics and Computer Science highlights the versatility of the mathematical model developed, which was adapted to identify areas with the greatest demand for ICU beds in Sao Paulo and to define systematic testing strategies for COVID-19. “We also collaborated with the state government of Rio Grande do Sul to determine the ideal time for economic activities to resume in various cities. Abstract mathematical principles may be hard for members of the public to understand, but work like this award-winning article can be appreciated by people other than specialists. I think this is fundamental for spreading the practice of multidisciplinary work in Brazil,” she says.

Since 2020, the SBMAC has been organizing the Kepler Prize to recognize national scientific production in applied mathematics. The 2024 winning entry integrated expertise from various fields and was a pioneer at the time, providing crucial and accessible information for decision makers.

Professor Tiago Pereira of the University of Sao Paulo’s Institute of Mathematical and Computer Sciences emphasizes how proud he was to receive an award that pays tribute to one of the founders of modern science. “Kepler was a great pioneer in data science, working on 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.