Is it time for the US to require covid vaccines on domestic flights?

A rebound in travel over the Christmas holiday coupled with a rise in covid-19 cases tied to the omicron variant caused staffing shortages at a number of US airlines, contributing to thousands of flight cancelations over the weekend.

More than 3,000 flights were canceled globally yesterday (Dec. 26), according to data from FlightAware, 1,517 of which were into or out of the US. Several airlines including Delta, United, and JetBlue attributed the cancelations to a rising number of workers calling out sick with covid-19.

The travel disruptions have revived discussions of what more should be done to protect both staff and passengers on US flights from the coronavirus. One approach is a vaccine mandate for domestic airline passengers, for which Anthony Fauci, the chief medical adviser to US president Joe Biden, signaled support today. Given the fact breakthrough cases seem to be more common with omicron, though, it’s not clear how effective such a mandate would be.

Fauci voices support for domestic vaccine mandate

International travelers are already required to show proof of vaccination to enter the US, but Fauci said today a mandate for American passengers flying within the country might not be a bad idea, either. “When you make vaccination a requirement, that’s another incentive to get more people vaccinated,” he told MSNBC. “If you want to do that with domestic flights, I think that’s something that seriously should be considered.”

Currently US travelers aren’t required to test for covid-19 before flying domestically. Several Democratic lawmakers called attention to this in a Dec. 20 letter urging the Biden administration (pdf) to implement new requirements for passengers to present proof of vaccination or a negative covid test before boarding a domestic flight.

Biden said at the beginning of the month he didn’t see a need for a domestic travel vaccine mandate, and White House press secretary Jen Psaki voiced concerns on Dec. 22 that it could delay flights. But she said the administration would implement one “if the health impact was overwhelming.”

Do breakthrough cases negate the value of a mandate?

Over the past two years US airlines have updated their cleaning procedures and air ventilation systems to prevent covid-19 transmission, and Fauci said over the weekend that these measures, coupled with masking requirements, should keep passengers “reasonably safe.”

Still, omicron poses a new challenge for the airline industry—a top medical adviser for IATA, the trade group representing the world’s airlines, said on Dec. 21 the variant doubles a passenger’s risk of catching covid-19 on a flight. Proponents of a vaccine mandate for domestic travel argue the public health measure would better protect everyone on board and assuage passengers’ concerns about flying during the pandemic. An October Morning Consult poll found 61% of Americans were in favor of a vaccine mandate for domestic flights.

Given the prevalence of breakthrough infections with omicron, though, it’s not yet clear a domestic vaccine mandate would be the most effective way to counter transmission. Most airlines experiencing staffing shortages, after all, already require their employees to be vaccinated.