Do pre-flight Covid-19 tests work?

Can preflight testing get people flying again?

The International Air Transport Association (IATA) thinks so. Last month, the trade association, which represents some 290 airlines around the world, called for the “development and deployment of rapid, accurate, affordable, easy-to-operate, scalable and systematic” Covid-19 testing for all passengers as a way to restore passenger confidence, bypass quarantines and reopen borders.

Within weeks, United Airlines, American Airlines and JetBlue announced plans to launch preflight testing programs to places such as Hawaii, Costa Rica and the Caribbean, depending on the airline.

By that time, Italy’s largest airline, Alitalia, was already operating two flights between Rome and Milan for passengers who tested negative before boarding.

The problem with a single test

Speed vs. accuracy

In calling for preflight testing last month, the IATA said that “deployable solutions are expected in the coming weeks.” Medical experts say that may be premature.

Polymerase chain reaction tests, also called PCR, can more accurately diagnose positive cases, said Dr. Peter Gulick, an infectious disease expert at Michigan State University. But those tests, which rely on a nasal swap, throat swab or saliva, “are run in a lab so it may take days to come back, and a patient may get infected during that time,” he said.

That is the rub with PCR tests. Test too early, and a person’s chances of being infected after the test increase. Test too late, and the results may not be ready by departure time.

Starting Oct. 15, American Airlines’ passengers traveling from Dallas-Fort Worth International Airport to Hawaii and Costa Rica can take Covid-19 tests at one of three places: the airport, local urgent care facilities or at home via a virtual meeting with a medical professional.

David Paul Morris | Bloomberg | Getty Images

Rapid antigen tests can solve the timing problem, but “they can result in 20% to 40% false negatives,” said Gulick. That makes those tests better suited to confirm infections, rather than to give an “all clear” indication of no infection.

Rapid PCR tests exist, but their production hasn’t yet matched demand, said Dr. Shira Doron, infectious disease physician and hospital epidemiologist at Tufts Medical Center.

“At this time, there are a few companies making rapid PCR tests,” she said. “These are sensitive and have few false positives.”

The incubation issue

Finding the ‘middle ground’