A recent study conducted by researchers at the University of California, Los Angeles revealed an alarming statistic on the effectiveness of airport screenings designed to remove sick passengers from flights: more than 50% of passengers infected for pathogens screened for at the airport are missed. These pathogens include SARS, Ebola, Middle East respiratory syndrome coronavirus, Marburg virus, Influenza H1N1 and Influenza H7N9.
Common measures used to detect illness such as fever screening fail to pick up diseases with a relatively long incubation period, such as Marburg and Ebola, although they are quite successful in detecting illnesses like swine flu. Moreover, devices used to measure fever only show less than 70% success rate. It is further speculated that passengers use fever reducers such as acetaminophen to reduce symptoms and/or conceal their fever.
In other measures, such as questionnaires surveying passengers about illness, only around 25 percent of passengers were found to actually answer honestly.
The researchers suggest that screening at airports can be improved given reliable data on the number of passengers who are turned away from the airport and actually report an illness as well as incentives for honest reporting.