During the Covid-19 epidemic, the CDC's visitors' Health Branch launched the Traveler-based Genomic Surveillance program, which uses nasal swabs and wastewater sample collection from arriving international visitors at US airports to identify new SARS-CoV-2 variants and other viruses.
As the head of the CDC's Travelers' Health Branch and the coordinator of its traveler genomic surveillance program, Dr. Cindy Friedman told CNN, "We have known that travelers are a very important population to consider for tracking new and emerging infections."
At the moment, the program runs Covid-19 surveillance at seven of the country's major international airports. Once a pilot program, it is currently being expanded to test at Boston Logan International Airport, San Francisco International Airport, Dulles International Airport in Washington, D.C., John F. Kennedy International Airport in New York, and more than 30 bacteria, antimicrobial resistance targets, and viruses, including influenza A and B and respiratory syncytial virus, or RSV.
When the CDC started gathering nasal swab samples from anonymous foreign visitors arriving at participating airports who volunteer to be swabbed in 2021, the traveler surveillance program was launched.
We began this as an idea. Could we persuade visitors arriving from all over the world to willingly provide us with a sample at the airport? said Friedman. "And could we obtain enough samples to do genomic sequencing and testing after that, so we could quickly ascertain what was entering our nation?"
Approximately 6,000 travelers volunteer each week for the surveillance program, which as of last month had tested over 370,000 travelers using nasal swab samples. More than 14,000 samples have been sequenced for additional analysis by the program, which has collected samples from tourists from more than 135 nations.
The wastewater program was launched in August 2022 and uses a specially designed collection device to gather wastewater from a single plane. After that, samples are sent to a lab for RT-PCR analysis. Samples that test positive for a particular pathogen, like Covid-19, are subjected to whole genome sequencing in order to identify any variations.
Since the program's inception, the agency has collaborated with Ginkgo Bioworks, a biotech company focused on creating a global biosecurity infrastructure to enable governments, communities, and public health leaders to prevent, detect, and respond to a wide range of biological threats. Matthew McKnight, the general manager of biosecurity at Ginkgo Bioworks, adds that surveillance programs like TGS are created in part to help prevent another health crisis, like the Covid-19 pandemic, from occurring. “One sample from an aircraft coming from a geographic destination afar can give us information potentially about 200 to 300 people that were on that plane,” says Friedman.
"The idea is to implement comparable initiatives in numerous locations throughout the globe, resulting in significantly earlier identification than when a patient presents at a hospital with a developing illness," McKnight explained. The question would be, "How can a pandemic be prevented?" When something is discovered very early on, it can be incorporated into the vaccine production process much more quickly. We don't have as much of that early warning as we would like these days. And these are only its initial phases.
According to Friedman, TGS has identified numerous Covid-19 variants, such as Omicron BA.2, BA.3, XBB, and BA.2.86, that were entering the country up to six weeks prior to their official national reporting. These variants were discovered through wastewater testing and nasal swabbing. She stated that as the cold and flu season intensifies, the program's current focus is on tracking newly discovered respiratory viruses.
As of right now, the CDC reports that the rate of Covid-19 hospitalizations is stable, with slightly over 15,700 hospital admissions per 100,000 persons during the week ending on October 28. With just under 600 deaths reported, the number of Covid-19-related deaths hasn't changed significantly over the past week either.
According to CDC data, flu activity is still low even though the country's flu season is gradually getting worse. Public health laboratories reported 189 cases of influenza for the week ending October 28, of which 77% were influenza A cases and 23% were influenza B cases.
Friedman stated, "We are interested in these respiratory pathogens that fall." "We want to be able to sequence them so we can determine the strain's genomics."
Friedman also emphasizes the significance of understanding whether virus strains are evolving and pinpointing the nations from which they are originating.
"There are numerous blind spots throughout the world with little testing and oversight," the speaker stated. "Generally speaking, we concentrate on airports that serve as global hubs and receive flights from a wide range of international destinations."