As the COVID-19 pandemic gained momentum, many countries entered lockdowns, or severely restricted the public movement of their citizens. This included school and university closures. However, the adverse impact on education induced much research on the actual role of students in the spread of the virus, leading to the reopening of these institutions in many regions.
Now a new study, which appeared on the preprint server medRxiv* in December 2020, shows that while students generally showed a high degree of compliance with restrictive measures such as masks and social distancing, they continued to contract the infection – from off the campus.
University Students. Image Credit: 4 PM production/Shutterstock.com
Preparations for Reopening
Many educational institutions are planning to reopen early next year, for the spring semester. On the other hand, the number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is rising rapidly over the country. Thus, educational authorities and college leaders are attempting to understand how viral spread correlates with the mode of instruction – remote or in-person – and whether the presence of students in residence on the campus affects transmission. The current study is based on open-source data from 9 such institutions in greater Boston and 4 from outside this area.
When colleges and universities in Boston expressed their intention to begin in-person classes in the fall, there was no shortage of viral testing in the form of reverse transcriptase-polymerase chain reaction (RT PCR).
The Broad Institute itself served more than 100 institutions, being able to handle over 1,00,000 tests every single day. Other large universities were able to process 6,000 tests a day for their student and faculty community.
This allowed these institutes to set up regular surveillance programs at high frequency for their campuses. The idea was to couple such testing with isolation and contact tracing on the campus, thus compassing rapid disease control before secondary spread occurs. This mandates that close contacts be isolated within the latency period, that is before the infected individual becomes infectious.
Risk Factors for Community Transmission Among Undergraduates
The researchers sought to understand how infection acquisition on campus among undergraduate students varied with the number of students living on campus, the density of students in their accommodations, the mode of instruction, and the cadence of testing.
Many other important factors include the degree of ventilation, mask-wearing, use of dining space, turnaround time, and even sample collection methods, along with the pattern of social networking in the student population.
The regional institutions were included in the study to clarify the effect of institutional policy on the outcome. If national-level statistics were used instead, the variations in the rate of COVID-19 in the surrounding community could overwhelm the pattern of spread on such campuses. The samples in the study cover 100 days.
The researchers predicted that if all new campus infections were because of the interactions of students and the surrounding local community, the incidence among groups of students would not depend on either the total student population on campus or the density of students in the dormitory. Transmission among students themselves would be revealed by a strong correlation between the number of infections and dormitory density.
No Evidence of Campus Transmission
The incidence among the colleges in the Boston area was ~16/1,00,000 person-days, which is not sharply different from the mean case rate of ~11/1,00,000 in Middlesex county, Massachusetts, over the same period. This shows that local educational institutes are contributing only a small part of the total number of cases in the country and not a disproportionate contribution, either. Moreover, the regular campus surveillance may quite well result in a higher case detection rate due to the turning up of asymptomatic cases.
Secondly, the fractional incidence among students shows no apparent relation with the total number of students in dormitories or with the dormitory student density. Thirdly, the researchers looked at whether the college adopted remote learning, with all classes being online; or hybrid instruction, with some in-person classroom learning. They found that there was no significant difference in the infection rates with the mode of instruction.
And finally, the frequency of testing shows that schools that conducted tests two or three times a week had fewer infections relative to those which conducted weekly tests. This may not be due to more testing alone, but rather due to the association of higher test frequency with stricter limits on social interactions on campus, as well as adaptations of accommodations, for instance, to minimize the spread of infection.
Implications and Future Directions
The results are consistent with the hypothesis that most student infections were acquired outside of the dorm-residential setting, with minimal community transmission within congregate on-campus student housing.”
Further analysis is required to determine whether test-isolate-quarantine policies help to effectively break the chain of transmission. For instance, the number of new infections in the quarantined student population after being exposed to known cases should be available.
On the whole, institutions in Boston that tested at least weekly have kept their COVID-19 incidence within bounds while preventing a prolonged uncontrolled campus outbreak.
Such continuing evaluations of how institutional policy affects infection rates could help shape decision-making and implementation in the areas of reopening and campus management. This would be facilitated by publicly available data on the details of student housing, including the number of students per bathroom and per bedroom, policies and compliance rates concerning interventions like face masks and social distancing, the mode of instruction, and daily updates on the number of students in isolation and quarantine from all institutions.