Those travelers now have to submit to temperature checks and questioning. But scientific studies published by the National Institutes of Health have shown that similar protocols were largely ineffective during an outbreak of Swine Flu in 2009, as Government Executive pointed out in an article last week.

A study of screenings at Australia’s Sydney Airport during the Swine Flu pandemic found that fever was detected in 5,845 passengers during the roughly two-month period covered by the analysis. Only three of those individuals ended up having the virus, which is known in the scientific community as H1N1.

Researchers determined that 45 patients who acquired the illness overseas would have “probably passed through the airport” during the roughly two-month period covered in the study. That means the screeners likely missed the vast majority of individuals who arrived at the facility with Swine Flu, despite grabbing thousands of travelers who showed signs of fever.