As coronavirus cases rise again in nearly every US state, the big question is: how can we stay safe while resuming normal life, especially in crowded spaces such as college campuses? Over the past two years, policymakers have been forced to make choices on everything from vaccination and mask mandates to occupancy limits, based on ever-changing assumptions about COVID-19.
Now, USC researchers have helped quantify the effectiveness of some of the most debated mitigation strategies by simulating the spread of COVID-19 on a college campus, specifically by modeling the airborne transmission risks associated with classes. in person.
the new study, published in the Proceedings of the National Academy of Sciences (PNAS), shows that during the highly transmissible Delta variant outbreak, at least 93% of students should be vaccinated, with everyone wearing masks indoors, to avoid an increase in cases. For the original strain of COVID-19, 23% of students are expected to be vaccinated, with everyone wearing masks indoors (or 64% of students without a mask).
These results will help decision makers in the event of ongoing COVID-19 epidemics or an outbreak of a similar infectious disease. The simulation model also allows policy makers to explore what-if scenarios relating to the spread of COVID-19 in classrooms by varying the parameters to see the outcome in different scenarios, such as hybrid classrooms, vaccination rates current, masking protocols, community levels of infection and different levels of viral infectivity.
“We’ve dabbled in a lot of these things over the past two years, but this gives us a more concrete, data-driven process.” Bhaskar Krishnamachari.
“I think the hardest thing about the pandemic has been finding the right balance – there’s a tension between having some sort of normalcy to live our lives and also protecting ourselves,” said the co-author of the study. Bhaskar Krishnamachariprofessor of electrical and computer engineering and computer science.
“This document contributes to a more lucid reflection on when we can be in operating mode in person, with or without a mask, and when we must impose vaccines. We’ve dabbled in many of these things over the past two years, but this gives us a more concrete, data-driven process to follow. It doesn’t have to be an arbitrary or political decision. This tells us that scientifically there is nuance.
Entitled “Simulating the transmission of COVID-19 in the classroom on a university campus”, the study is written by Arvin Hekmati, who holds a doctorate in computer science. student; Mitul Luhar, professor of aerospace and mechanical engineering; Bhaskar Krishnamachari, Professor of Electrical and Computer Engineering and Computer Science; and Maja Mataricprofessor of computer science, neuroscience and pediatrics.
Highly granular data
The research is particularly relevant during the early days of an infectious disease outbreak when policy makers are faced with the difficult decision to order school closures. Using a simulation of the spread of COVID-19 based on anonymized real-world data from a major university, researchers projected the impact of various school reopening strategies: full, hybrid, in-person closure; vaccinated and unvaccinated; masked and unmasked.
In a first-of-its-kind study, the model accounts for highly granular data such as class times, classroom sizes, occupancy, ventilation rates, as well as vaccine rates and effectiveness, and even information specific to classroom interactions, such as the role of speech and disease transmission in an enclosed space.
“Nothing should be done by guesswork; we can quantify every aspect of this outbreak and make the best decision. Arvin Hekmati.
The results showed that without vaccination, moving 90% of classes online can reduce new infections by up to 94%, while universal mask use can reduce new infections by up to 72%.
“With this tool, universities don’t have to make these decisions without knowledge — they can make informed decisions for university policies to keep students, faculty, and staff safe,” Hekmati said. “Nothing should be done by guesswork; we can quantify every aspect of this outbreak and make the best decision. »
Opportunity and responsibility
Researchers from the fields of computer science, electrical engineering, and aerospace engineering have teamed up to work on this paper, which draws on expertise in both large-scale computational modeling and mechanistic transmission modeling of COVID- 19.
“As a university, we have the opportunity and the responsibility to study our own community in order to obtain information to inform the general public,” Matarić said.
“This project was extremely satisfying as it brought together colleagues from several departments of the Viterbi School who enabled analysis and modeling, which in turn provided information on university campus security policies in the event pandemic.”
To inform the model, Professor Luhar, an expert in indoor airborne dispersion modeling, analyzed the transmission mechanisms of COVID-19, taking into account everything from room size to the number of people present, and how much they talk, which can lead to variability. in virus emission rates by instructors and students.
During class, for example, instructors will tend to speak much more often than students, which could influence transmission rates. “Providing these facts in the model made it very compatible in the case of universities and classrooms,” Hekmati said.
In future work, the team hopes to expand their research to include a tool that could be used by campus administrators at large universities and workplace campuses. Although this model is specifically designed for classrooms, many modular aspects could be modified to extend to other types of environments, the researchers said.
“Nothing gives us more satisfaction as engineering researchers than having a positive impact on society,” said Krishnamachari, who is also Hekmati’s advisor. “Most of us, when we started engineering school, dreamed of doing meaningful work that helps others, and I’m very happy for Arvin that he worked on a project where he can see that kind of positive impact.”
Posted May 26, 2022
Last updated May 26, 2022