A CDC airport surveillance program found the earliest known US cases of Omicron subvariants

An airport-based coronavirus surveillance program in the US for travelers arriving from abroad detected the first known US case of the highly contagious Omicron subvariant BA.2 in December, according to a new study. The results, which have not yet been published in a peer-reviewed journal, suggest that pooled testing of international travelers may be an effective and efficient way to keep tabs on new variants and pathogens. “Travelers are really an important population when tracking new and emerging infectious diseases because they’re mobile, they have the potential for exposure to disease during travel and they can spread disease from one place to another,” said Dr. Cindy R. Friedman, chief of the Travelers’ Health Branch at Centers for Disease Control and Prevention, and the study’s lead investigator. The program actually detected the first known US cases of two Omicron subvariants, BA.2 and BA.3, which are similar to, but genetically distinct from, BA.1 and B.1.1, the versions of Omicron that drove a winter surge in US cases. The voluntary program, which screened more than 16,000 travelers this fall and winter, was conducted by the CDC and two commercial partners: the XpresSpa Group, which offers testing in airports, and Ginkgo Bioworks, a biotech company with a testing initiative and a network of laboratories across the country. The program combined nasal samples from multiple people arriving from the same country or on the same flight — an approach, known as pooled testing, that allows scientists to search for the virus in multiple people at once. The researchers hope to expand the traveler surveillance program and are also preparing to launch a pilot study that will search for signs of the virus in the wastewater from airplane bathrooms, Dr. Friedman said.<br/>