Last January, it seemed like a good strategy to conduct testing at U.S. airports to screen passengers from countries with widespread transmission of COVID-19. The goal was to identify travelers who were sick, separate them from other passengers, and collect their contact information so it could be shared with the passenger’s local public health department. That way, it would be possible to reduce the importation of COVID-19 cases into the U.S.
Now it turns out that screening has proven to be ineffective, according to new research from the U.S. Centers for Disease Control and Prevention (CDC).
Published in the CDC’s Morbidity and Mortality Weekly Report, a new study shows that conducting temperature checks and monitoring symptoms among travelers from countries known to have a high rate of virus spread not only required considerable resources, but it did little to stop the spread of the virus. In fact, the study found that in tests conducted between January 17 and September 13, the CDC was able to identify roughly one active case of COVID-19 per 85,000 travelers.
Specifically, the CDC -- with support from the U.S. Department of Homeland Security -- screened 766,044 passengers at airports during the 8-month program. Of those passengers, only 298 reported potential exposure or symptoms that required an additional assessment. Surprisingly, just 35 passengers were tested for coronavirus -- and only nine of them received positive test results.
The obvious question then is this: Why didn’t the testing protocol work?
It turns out that there are many reasons. First, COVID-19 has a wide range of nonspecific symptoms common to other infections. It also has a relatively long incubation period. What’s more, there also have been a high number of asymptomatic cases that could not be adequately screened. Finally, while some travelers may have denied symptoms or taken steps to avoid detection, it’s also possible there simply was a low presence of COVID-19 among screened travelers.
Instead of a focus on screening, the CDC now recommends a different approach.
Indeed, the findings highlight “the need for fundamental change in the U.S. border health strategy,” the CDC said. The agency goes on to say that travelers and their local communities would be better protected if there was a “more efficient” collection of contact information for international air passengers before they arrive and real-time data that could be sent to U.S. health departments.
Pre-departure testing within 72 hours before the trip and testing upon arrival would also help, as would rules that would encourage a traveler to self-isolate for a certain period, the CDC said.
Another study shows that COVID exposure on a flight is "virtually nonexistent." You can read more about the study here.