To head off an outbreak of Ebola in the U.S. late last year, federal authorities moved to increase screenings of passengers at American airports for signs and symptoms of the disease. But new research suggests such inspections can miss half or more of travelers infected with transmissible diseases.
The findings, published in the journal eLife, indicate one of the biggest barriers to effective screening of passengers is the lack of honest reporting by travelers about their risk of exposure — if being honest could put them at risk of delay.
The researchers from the University of California-Los Angeles and the London School of Hygiene and Tropical Medicine have identified several ways to make current screening more effective. Among them: making airport arrival screenings more comprehensive and tracing — then containing — potential cases highlighted by airport questionnaires.
The researchers used a mathematical model to analyze screening for six viruses: SARS coronavirus, Ebola virus, Middle East respiratory syndrome coronavirus (MERS-CoV), Marburg virus, Influenza H1N1, and Influenza H7N9.
"We found that for diseases with a long incubation period such as Marburg and Ebola, taking passengers' temperature to test for fever is particularly ineffective at the start of an epidemic but does pick up more cases as it stabilizes," said researcher Katelyn Gostic from the Lloyd-Smith Lab at UCLA.
For the early phase of these disease epidemics, questionnaires are the most effective detection method.
"With diseases such as swine flu that take a shorter time to incubate, fever screening is the most effective method throughout an epidemic," she said.
Fever screening on arrival has been criticized for being particularly ineffective, but the scientists found it can catch cases missed at departure. Infrared non-contact thermometers will pick up fevers 70 percent of the time. Also, symptoms of some diseases will progress during transit so can be easier to detect on arrival.
Understanding how each disease progresses can improve detection by making sure the right questions are asked in surveys.
"Honest reporting can not only improve on-site detection but is essential to enable authorities to follow up with travelers who may have been exposed but have not yet developed symptoms," said Gostic. "We need to find ways to incentivize better self-reporting."
The research was funded, in part, by the National Institutes of Health and the National Science Foundation and the Medical Research Council in the UK.
© 2026 NewsmaxHealth. All rights reserved.