Optimizing COVID-19 testing strategies on college campuses: Evaluation of the health and economic costs

Colleges and universities in the US struggled to provide safe in-person education throughout the COVID-19 pandemic. Testing coupled with isolation is a nimble intervention strategy that can be tailored to mitigate the changing health and economic risks associated with SARS-CoV-2. We developed a decision-support tool to aid in the design of university-based screening strategies using a mathematical model of SARS-CoV-2 transmission. Applying this framework to a large public university reopening in the fall of 2021 with a 60% student vaccination rate, we find that the optimal strategy, in terms of health and economic costs, is twice weekly antigen testing of all students. This strategy provides a 95% guarantee that, throughout the fall semester, case counts would not exceed twice the CDC's original high transmission threshold of 100 cases per 100k persons over 7 days. As the virus and our medical armament continue to evolve, testing will remain a flexible tool for managing risks and keeping campuses open. We have implemented this model as an online tool to facilitate the design of testing strategies that adjust for COVID-19 conditions as well as campus-specific populations, resources, and priorities. As a part of the COVID-19 response team at a large public university in the US, we developed an online analytic platform to aid administrators in weighing the costs of massive testing programs against the potential risks of letting COVID-19 spread unchecked. We apply the approach to derive a cost effective screening policy for a large public university in the fall of 2021. By then, SARS-CoV-2 tests were relatively inexpensive and widely available, yet many universities were legally prevented from requiring testing, the Delta variant was surging, and vaccine coverage among college students was limited. We demonstrate the versatility of the approach for tailoring university mitigation strategies depending on the nature of the pathogen threat, the composition of the campus population, and the resources and priorities of the institution.