The Boston College campus comprises approximately 1,000 faculty, 14,000 undergraduate and graduate students and 3,000 staff working and learning on 240-acres. The student body lives primarily in high occupancy residence hall settings, takes meals in community settings (dining halls) and faculty and students congregate in classrooms and lecture halls on a daily basis. A robust strategy for mitigating chains of viral transmission in the campus community includes a combined strategy of social distancing and mandatory mask use, as well as viral testing, contact tracing, quarantine/isolation and support.
In the context of a population-dense university campus with individuals living, dining, and learning together, the identification of virus-positive individuals must occur in a rapid timeframe – on the order of minutes to hours – in order for contact tracing and mitigation strategies to effectively suppress chains of viral transmission. Rapid testing and contact tracing also allow for real-time adjustments to mitigation policies, for example, through the identification of activities or locations on campus that appear to contribute disproportionately to viral spread. Although testing is available through contract labs, hospitals, and urgent care facilities, the turnaround times are on the order of days, which renders contact tracing and isolation/quarantine efforts ineffective within the context of a highly populated university campus. For this reason, BC has implemented a combined strategy of surveillance testing utilizing the Broad Institute and on-site, rapid testing of individuals displaying symptoms indicative of SARS-COV-2 infection.
The current “gold-standard” for diagnosing ongoing infection is the multiplex quantitative RT-PCR assay, which can reliably detect very low levels of virus as early as day 3 post-infection, coinciding with the earliest time points at which an individual becomes competent to transmit virus to other individuals through close physical contact. This form of testing, if deployed effectively, can be used to identify infected individuals and prevent further transmission. The assays selected for deployment on the Boston College campus are the ThermoFisher COVID TaqPath assay and the Cepheid Xpert Xpress SARS-CoV-2 assay, both of which use multiplex RT-PCR and have FDA Emergency Use Authorization. The former is a high-complexity, high-throughput RT-PCR assay (384 samples every 3-4 hours) and the latter is a low-complexity point-of-care assay (1 sample per 45 minutes).
Boston College health care personnel and trained virologists have extensive experience and are proficient with RT-PCR technology, and have been trained in the FDA-EUA approved protocols. The chosen assays have among the highest documented specificity and selectivity in their respective classes, thus limiting the number of false positives and false diagnoses that would otherwise overburden isolation and quarantine infrastructure.
The combination of these two testing protocols allows for 24-hours-per-day, seven-days-a-week rapid diagnosis of symptomatic individuals in the campus community. Thus, from the time an individual is sampled (nasal or nasopharyngeal swab) until diagnosis ranges from 45 minutes to 4 hours. During this time, the individual patient can reasonably remain in isolation, and if a positive diagnosis occurs, on-campus trained contact tracers can immediately determine such things as whether the individual lives on or off campus, which classes (in the case of a student or faculty member) they’ve attended in the previous days (and where in the room they sat and next to whom), which cafeterias they’ve eaten in and when, along with other critical, pre-existing information. Interviews by contact tracing staff can also add additional relevant information to help identify potential contacts (classmates, roommates, co-workers, etc.) for possible testing, isolation and observation in order to further suppress possible transmission in the campus community.
Submitted to the University by Welkin Johnson, Professor of Biology, Chair of the Biology Department, August 2020