The US Centers for Disease Control and Prevention is expanding its infectious disease surveillance program at four major US airports to more than 30 pathogens, including flu, RSV and other respiratory viruses.

The Traveler-based Genomic Surveillance program, led by CDC’s Travelers’ Health Branch, was introduced during the Covid-19 pandemic to detect new SARS-CoV-2 variants and other pathogens through nasal swab and wastewater sample collection from arriving international travelers at US airports.

“We have known that travelers are a very important population to consider for tracking new and emerging infections,” Dr. Cindy Friedman, who leads the CDC’s traveler genomic surveillance program and is the chief of the agency’s Travelers’ Health Branch, told CNN.