By Jeffrey Roland
Everyone wants college students to return in person for the fall semester. How do we make that happen safely?
The surest way would be with mandated vaccination against COVID-19. This is why the American College Health Association has formally recommended COVID-19 vaccinations for students. This is why 540 colleges around the country, many of them public, have already mandated vaccination for students returning in person for Fall 2021. This is why, on June 18, the LSU Board of Supervisors—prompted by similar, separate actions by LSU, Baton Rouge faculty and students—voted to mandate COVID-19 vaccinations for students attending the universities’ various campuses.
This mandate, however, will not go into effect without at least one of the existing vaccines receiving full FDA approval. With fewer than one in three college-aged adults fully vaccinated in Louisiana, returning in person to Louisiana colleges this August will require serious mitigation measures against the spread of the COVID-19 virus (SARS-CoV-2) and its rapidly evolving variants.
We know much more now about the science of transmitting the COVID-19 virus than we did in the summer of 2020. Infection with the COVID-19 virus is a function of level (how much) and time (how long) of exposure to the virus. With in-person instruction, time of exposure is time spent in the classroom for a given instructional period: one to three hours.
The greatest exposure risk indoors comes from aerosolized virus. This makes mitigation in classes a matter of minimizing the amount of aerosolized virus (viral load) in the classroom.
Aerosols behave a lot like smoke. They linger in the air, can travel long distances in a room, and in sufficient concentration can have effects for hours after their source has left. Minimizing the viral load in an enclosed space is much like trying to keep a room free of smoke. To accomplish this, with smoke or aerosolized virus, the available tools are ventilation and filtration.
The most important factor in minimizing viral load is proper masking. Air changes per hour (ACH) run a close second.
An ACH rating of 4 for an HVAC system means that the air in areas serviced by that system is completely replaced with fresh air every fifteen minutes (i.e., four times an hour). An ACH rating of 4 is minimum safe for a typical classroom to remove aerosolized COVID-19 virus.
For that reason, we must ensure that HVAC systems on every college campus in Louisiana have ACH ratings of at least 4. Given the age of campus infrastructure in Louisiana, it’s unlikely that our current HVAC systems do.
HVAC systems not meeting this minimum-safe ACH rating can be helped by exhaust fans, internal filtration with a MERV rating of 13+, and portable HEPA filtration units. But to ensure effectiveness, installation of these remedies must be overseen by a certified environmental engineer specializing in air quality, not already overburdened campus facilities managers.
Why worry about infections by the COVID-19 virus among college students? There are at least three reasons.
First, infections in any population enable the virus to mutate into variants that threaten the vaccinated and unvaccinated alike. Second, the delta variant, which is expected to be dominant in the United States soon, presents a significant threat even to college-aged people. Third, the delta variant is 50% more transmissible than earlier variants.
Any outbreak in a student population would almost certainly force a repeat of Spring 2020, an abrupt and disruptive transition to remote instruction.
These outcomes are avoidable, but only if we implement appropriate mitigation measures now. August will be too late for our students’ health and education.
Jeffrey Roland is an Associate Professor of Philosophy at Louisiana State University, Baton Rouge.