While many worried during the heat of the pandemic that college campuses would be COVID hot spots, a new study out of Boston University shows what strategies worked to limit the virus’ spread on campus.
The study from Boston University’s COVID Clinical Testing Lab and Contact Tracing — along with researchers from Boston University Chobanian and Avedisian School of Medicine — has found that public health interventions prevented transmission for most COVID case introductions at BU.
Only two major campus outbreaks were identified from January to May 2021, according to the scientists.
The university’s test-trace-isolate strategies were “highly effective in limiting respiratory infection transmission,” the researchers said. These findings have implications for transmission protocols for other respiratory diseases and possible future outbreaks, they noted.
“We found that genetically linked cases overlap with outbreaks identified by contact tracing; however, they persisted in the university population for fewer days and fewer rounds of transmission than originally estimated via contact tracing,” said corresponding author John Connor, an associate professor of microbiology at the School of Medicine.
“This underscores the effectiveness of test-trace-isolate strategies in controlling undetected spread of emerging respiratory infectious diseases,” added Connor, a researcher at the Boston University National Emerging infectious Diseases Laboratories. “These approaches limit transmission from those people outside the university as well as those who caught the disease from someone within the campus community.”
In April 2020, BU enforced weekly surveillance testing, social distancing, masking and prohibited school-sanctioned social events. People who tested positive were isolated for 10 days by moving into on-campus isolation housing or isolating at private off-campus residences.
To track and limit infection spread, the university performed contact tracing to identify likely transmission pathways through interviews of all test-positive individuals and known contacts. This information was then coupled with viral genomic sequencing for both asymptomatic and symptomatic cases to confirm likely transmission events.
Viral genomic sequencing captured 767 unique SARS-CoV-2 genotypes on the BU campus during the spring 2021 semester. Of these, they noted 696 genotypes (91%) only once, making it unlikely that they established on-campus transmission chains.
The few genotypes with multiple observations usually showed transmission bubbles of less than five individuals; only seven genotypes (about 1%) included more than five samples. According to the researchers, these findings highlight the ability of testing, tracing, and quarantine approaches to limit respiratory transmission in a complicated urban environment.
First author Jackie Turcinovic, a PhD candidate in the Connor lab, said, “Our analyses support the hypothesis that systematic interventions, such as population-level test-trace-isolate strategies, are highly effective in limiting respiratory infection transmission, even in the presence of continual importation of disease from outside the university population.”
