CDC: Nearly 11,000 possibly exposed to virus on flights

The Centers for Disease Control and Prevention has investigated 1,600 cases of people who flew while at risk of spreading the coronavirus, identifying nearly 11,000 people who potentially were exposed to the virus on flights.

But though the CDC says some of those travelers subsequently fell ill, in the face of incomplete contact tracing information and a virus that incubates over several days, it has not been able to confirm a case of transmission on a plane.

That does not mean it hasn’t happened, and recent scientific studies have documented likely cases of transmission on flights abroad.

“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.

“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,” Shockey wrote in an email.

She said that though the agency has received information about people who may have been exposed on flights subsequently becoming ill with the novel coronavirus, pinpointing when someone was exposed is difficult.

Local health authorities also might not be able to test people reported as exposed or share test results with the CDC, she said.

In guidance for the public, the CDC acknowledges that viruses do not spread easily on planes because of the way the air is filtered, but it also emphasizes that air travel means being in close proximity to people for long periods and encountering frequently touched surfaces on planes and in airports.