The risk of being exposed to the virus can be reduced by 23% to 57% on one-way and two-way flights when intermediate seats are available compared to a full occupancy flight, according to the study published Wednesday by the U.S. Centers for Disease Control and Prevention.
Researchers from the CDC and Kansas State University used laboratory models to simulate how much exposure to virus particles could be reduced when center seats are kept vacant in an aircraft cabin.
The models were based on the spread of bacteriophage aerosols used as a surrogate to estimate the airborne spread of coronavirus. Bacteriophages are viruses that can infect bacteria. The analysis did not measure the effect of wearing masks, which is currently required on flights, but the researchers noted that some viral aerosol can still be emitted from an infectious masked passenger, and that distancing can still be helpful.
The models suggested that risk reduction with vacant middle seats ranged from 23%, which was observed for a single passenger who was in the same row but two seats away from an infectious passenger, to 57%, observed when middle seats were vacant across a section of three rows containing a mixture of people with Covid-1
“When the infectious and other passengers who would have had intermediate seats were removed, leaving six infectious passengers out of 12 total passengers left in the window and aisle, a reduction of 57% exposure was observed,” the researchers wrote in their study.
Overall, it is “important to recognize that the current study only concerns exposure and not transmission,” the researchers wrote. More research is needed to determine the risk that the virus may be transmitted and cause disease.
Latest update for travel guide
The agency said that as long as precautions are taken against coronavirus, including mask wearing, fully vaccinated people can travel in the United States without being tested for Covid-19 before or after self-quarantine.
For international travel, fully vaccinated people do not need a Covid-19 test before travel – unless required by the destination – and do not need self-quarantine after returning to the United States. They should still have a negative Covid-19 test before boarding a flight to the United States, and a follow-up test three to five days after their return, the CDC noted.
The CDC considers someone fully vaccinated two weeks after receiving the last required dose of the Covid-19 vaccine. The updated instructions do not apply to unvaccinated persons. The CDC advises anyone who is not fully vaccinated to continue to avoid travel.
All Americans, regardless of vaccination status, must wear a mask and practice public health measures such as physical distance and hand washing frequently, the CDC says.