A Duke University effort to minimize COVID-19 virus spread among students this fall was successful largely through aggressive testing and the comprehensive embrace of responsible personal behaviors by the campus community, several health experts said Wednesday.
The effort launched in August when all enrolled students were asked to self-quarantine for 14 days prior to arriving on campus. They were also asked to sign a code of conduct pledge, wear masks and follow social distancing guidelines.
Once classes began, the university also conducted regular surveillance testing using a pooled-sample technique to test more samples quicker, and engaged in other mitigation efforts as well.
The result: The average per-capita infection prevalence among students was lower than in the surrounding community, and large outbreaks seen on other campuses were avoided. Overall, combined testing approaches identified 84 cases among students, with 51% occurring among asymptomatic people.
This success was in large part due to the willingness of faculty, staff and students to follow health guidelines closely, said Kyle Cavanaugh, Duke’s vice president for administration.
“It would be hard to identify a portion of Duke that actually hasn’t played a role,” Cavanaugh said. “It was the totality of this community engaging in every aspect you can think about.”
Cavanaugh was one of five Duke experts who took part in a virtual media briefing Wednesday, a day after the publication of a case study on Duke’s experience in the CDC’s Morbidity and Mortality Weekly Report.
More information on that case study is available here.
Duke asked students to show up twice a week for COVID-19 tests, and they did so with a 95 percent compliance rate, Cavanaugh said.
“We’re incredibly fortunate that our student body has been nothing short of phenomenal. We certainly had our share of small brushfires, but that’s what they were: Small brushfires,” he said. “We had a very, very busy student affairs disciplinary semester, much more than we normally do, and I think the aggressiveness paid off.”
Duke employed a pooled-testing technique in which five samples were grouped together and analyzed for the presence of the virus. Batches that registered positives were then broken into individual samples and tested separately to identify the source of the positive. The Duke Human Vaccine Institute processed 80,000 samples from August-October.
This testing technique proved effective, but not in a vacuum, said Mattia Bonsignori, an associate professor of medicine in the Duke Human Vaccine Institute.
“One key aspect of our process was that we didn’t limit to a single population, not to just students, or faculty or staff,” he said. “We didn’t limit to just testing; there was strong encouragement and emphasis on social distancing, on masking, on hand-washing. The university did a lot of other measures, like packaged food … that really all tried to curb the problem from different angles. This kind of model can be adopted just by looking at the specifics of an environment.”
Added Thomas Denny, CEO of the Duke Human Vaccine Institute:
“Testing is important, but it’s a marker of behavior. At Duke, we had a unified message of behavior and the community followed it. The testing helped us pick up where we were having some problems that we were then able to be aggressive and contain it.”
Here are more excerpts from the media briefing:
ON WHETHER POOL TESTING IS ALWAYS THE RIGHT TOOL
Dr. Tony Moody, associate professor of pediatrics
“If you get to the point where you have very high incidents … it very well may not be useful to continue pooling. The numbers start to work against you as your incidence rate starts to rise. We’ve been lucky to have a relatively low infection rate. We’re using fewer clinical tests by doing this.”
ON CHALLENGES PRESENTED BY ASYMPTOMATIC PEOPLE WHO HAVE THE VIRUS
“What is most important to outline – over 50 percent (of positive findings) came from asymptomatic students. Said differently, had we not had the progressive surveillance testing of our asymptomatic population, we would have missed those.”
“We had a couple of really significant wins, especially in some off-campus experiences, where we identified an individual who tested positive for asymptomatic testing. Through aggressive contact tracing, we placed eight students into quarantine, and those eight students subsequently tested positive. It was a great way of tying off a significant possible outbreak.”
ON THE ROLE ‘DE-DENSIFYING’ RESIDENCE HALLS PLAYED
“Each undergraduate student on the campus actually resided in a single room. There were shared bathrooms, but a single room. We’re confident that played a significant role. How that plays when you start multiplying by tens of thousands becomes clearly much more complicated in an environment much larger than ours.”
“The de-densifying effort has to be something we take very seriously.”
ON HOW OTHER UNIVERSITIES CAN ADOPT DUKE’S SURVEILLANCE TESTING MODEL
“Scaling is a challenge. What this takes is innovation. It takes a talented faculty and experience on a campus to come together and look for how to innovate.”
“No one size fits all. We happen to have some infrastructure and technology that was a good fit for us. It was not the perfect fit but it was a good fit. I would just say to other universities: Look within. All of these universities, large universities, are doing molecular biology – it’s a matter of taking an assay and applying that and applying it in a good, reproduceable fashion.”
“The challenge is to just be an innovator in your unique setting. See what tools you have in your toolbox and work to redeploy them to meet this need.”
ON THE IMPORTANCE OF SIMPLICITY
Dr. Tony Moody
“We specifically tried not to overcomplicate things where they could be simple. We made a bunch of decisions early on … and we specifically tried to make things as easy as it could be.”
“By having distributed testing centers and not funneling everybody into a central location, we cut down on lines where transmission could occur. We made it very simple for everyone to engage. We made it as easy as we could. That has really paid dividends for our testing program.”
ON WHAT WAS LEARNED ABOUT VIRUS TRANSMISSION IN THE CLASSROOM
Steven Haase, associate professor of biology and medicine
“What we’ve learned over this semester – and there was great concern that we’d see transmission on campus, in classroom settings for example – in our experience so far, transmissions are not occurring in a classroom setting. This fits with the discussions we’ve had with our sister institutions that the kind of classroom learning we’re doing … is not contributing to on-campus spread.”