The Centers for Disease Control and Prevention is investigating at least 1,600 cases of people who flew while at risk of spreading the coronavirus. After contact tracing, the CDC says nearly 11,000 people have been potentially exposed to the virus on flights.

The agency told The Washington Post that it has not confirmed a case of transmission on a plane, but that doesn’t mean it didn’t happen.

“An absence of cases identified or reported is not evidence that there were no cases,” said Caitlin Shockey, a spokeswoman for the CDC’s Division of Global Migration and Quarantine.

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Shockey added, “[The] CDC is not able to definitively determine that potential cases were associated (or not) with exposure in the air cabin or through air travel given the numerous opportunities for potential exposure associated with the entire travel journey and widespread global distribution of the virus.

The CDC has not changed its stance on acknowledging that viruses do not spread easily on an airplane because of how air is filtered. But the strongly advises against traveling and has released guidance stating, “staying home is the best way to protect yourself and other people from the virus.”

Studies show that the window seat is safer than sitting in an aisle if you do have to fly.

Researchers found that having a wall or barrier next to you that the window seat provides on a plane reduces the number of people within your “social distancing” space by half, as Travel Noire previously reported.

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