Vacant middle seats on airplanes cut COVID-19 exposure risk by up to 57%, CDC study says

Leaving middle seats open and vacant on airplanes may significantly reduce a passenger’s risk of exposure to the coronavirus, a new study published by the U.S. Centers for Disease Control and Prevention suggests.

Based on laboratory modeling of exposure to SARS-CoV-2 on single-aisle and twin-aisle aircraft, researchers with the CDC and Kansas State University found that exposure to the virus that causes COVID-19 was reduced by 23% to 57% in scenarios in which the middle seat was vacant in comparison with full aircraft occupancy.

"Research suggests that seating proximity on aircraft is associated with increased risk for infection with SARS-CoV-2, the virus that causes COVID-19," the CDC researchers wrote.

The models used bacteriophage aerosols as a surrogate for airborne SARS-CoV-2 and modeled the relationship between the virus’ exposure and aircraft seating proximity, including full occupancy and vacant middle seat occupancy scenarios.

According to the CDC, this study implies that physical distancing of airplane passengers, including through policies such as middle seat vacancy, could provide additional reductions in risk for exposure to SARS-CoV-2 on aircraft.

"My colleagues and I have many years of experience in measuring aerosols in the aircraft cabin environment, so the transport behavior was not surprising. We were surprised, however, by the complexity of analyzing seating arrangements in terms of virus exposure," a spokesperson with the CDC told FOX Television Stations.

RELATED: CDC clears domestic travel for vaccinated people, but still advises mask-wearing

The news comes after a recent investigation of SARS-CoV-2 transmission on an international flight, which found that seating proximity was strongly associated with infection risk. It found 75% of infected passengers were seated within two rows of the symptomatic passenger who likely originated the outbreak.

"Some airline carriers have been operating with a vacant seat policy, and this study supports the effectiveness of that intervention, in the context of other measures that are in place, such as masking, ventilation, and the ongoing vaccination efforts," the CDC spokesperson said.

It is important to recognize that the current study addresses only exposure and not transmission, and the impact of masking was not considered in the study.

"Future studies of transmission risk could encompass determinants that were not fully explored here such as mask use, virus characteristics, and host characteristics, such as vaccination status," the CDC spokesperson continued.

Current CDC guidelines recommend against travel for people who have not been vaccinated against COVID-19, and a January 2021 CDC order requires masking for all persons while on airplanes.

Earlier this month, the CDC announced that fully vaccinated people could travel safely within the United States.

"CDC recommends delaying travel until you are fully vaccinated, because travel increases your chance of getting and spreading COVID-19," the CDC announced in early April.

RELATED: Delta to stop blocking middle seats on May 1, joining other US carriers

According to the CDC, fully vaccinated travelers do not need to get tested before or after travel unless their destination requires it and do not need to self-quarantine, but fully vaccinated travelers are still asked to follow the CDC’s recommendations for traveling safely including: mask wearing, frequent hand washing and staying six feet from others.

Delta remains the only major airline blocking middle seats on all domestic flights through April.

"Since the onset of this crisis, U.S. airlines have relied on science, research and data to help guide decisions as they continuously reevaluate and update their processes and procedures. U.S. airlines have implemented multiple layers of measures aimed at preventing virus transmission, including strict face covering requirements, pre-flight health-acknowledgement forms, enhanced disinfection protocols and hospital-grade ventilation systems," Airlines for America, an airline advocacy organization, told FOX Television Stations.

Southwest and United Airlines did not immediately respond to a request for comment. American and Delta Airlines declined to comment, but pointed to Airlines for America for comment.