Keeping the middle seats vacant on airplanes—something major airlines did at the beginning of the pandemic and now only Delta does—could dramatically decrease Covid-19 exposure for passengers, according to a U.S. Centers for Disease Control and Prevention study published Wednesday.
CDC research found that when the middle seat is left open, relative virus exposure is reduced by between 23% to 57%, compared to full occupancy.
The highest reduction of exposure (57%) was observed in studies involving a vacant middle seat in three-row sections that contained a mix of infectious and non-infectious passengers.
The study used the bacteriophage MS2 virus as a substitute for Covid-19 to approximate the airborne spread of the coronavirus.
Researchers from the CDC note their report is subject to limitations and that it’s “important to recognize” the study released Wednesday “addresses only exposure and not transmission.”
Over the first few months of the pandemic, although there was no federal mandate requiring it, airlines prevented passengers from booking middle seats to limit the spread of Covid-19. Yet, by late March, Delta was the only major U.S. airline that continued to that practice. As they ramped up towards full capacity in 2020, the airline industry pointed to analysis affirming it was safe to travel aboard commercial flights. A study released in October conducted by the U.S. Transportation Command, on behalf of the Department of Defense, found that “overall exposure risk from aerosolized pathogens, like coronavirus, is very low.” A Harvard University study released that same month used computer models to determine that highly-efficient onboard ventilation systems filter out more than 99% of airborne viruses. Harvard researchers found that these filtration methods reduced the risk of Covid-19 transmission on board an aircraft to “below that of other routine activities such as grocery shopping” or eating at restaurants. However, other studies have highlighted how boarding and deplaning aircraft can lead to the spreading of the coronavirus, as can the activities associated with flying, such as going through security or waiting in close proximity to other passengers at the terminal.
In January, the CDC issued an order requiring the wearing of masks by all travelers over the age of two while boarding, disembarking, and for the duration of travel on public transportation, including planes. Earlier this month, the CDC said it “recommends delaying travel until you are fully vaccinated.”