Heather Reese The Traveler-Based Genomic Surveillance program, or TGS, was launched in 2021. It monitors for infectious diseases among arriving international travelers at select U.S. airports and consists of three complementary approaches. So, the first one is voluntary anonymous nasal swabbing of inbound international air travelers arriving at those select U.S. airports. That’s where we’ve just reached that 1 million participant milestone. And then the other components are aircraft wastewater sampling, either through individual aircraft and then also through a triturator location, which really acts as a combined pooled wastewater sample. So all those samples are sent to the lab, tested for COVID, flu A/B, RSV, norovirus, adenovirus and M-pox, and samples that test positive for select pathogens are then sequenced. Together, all those data help us get timely detection of pathogens with public health concern or emerging strains or variants.

Eric White For a program like this, the more the merrier and the better the data, the better you can tell if there are any strains of those diseases you’re scanning for. Can you just tell me about the significance of having 1 million participants in just, it only took about six years or so? I don’t even know if other government agencies would be able to pull that off so quickly.

Heather Reese Yes, since the TGS program is completely voluntary and anonymous, reaching 1 million international traveler participants since the program started in 2021 is actually a really significant milestone. It means the public is interested in supporting public health and disease detection, helping us react faster to these incoming disease threats. The program wouldn’t be possible without them.

Eric White Yeah, on the detection front, if you can explain what that means to have that sort of lead time and how that can help with any response efforts and if there’s any stories of success so far that you’d be able to share.

Heather Reese The TGS program allows us to use the air travel network for timely detection of pathogens of public health concern or these emerging strains or variants when international travelers land at the airport. And this is often before they’re circulating broadly within U.S. communities. So a great example of this was this past summer, the TGS program together with CDC influenza scientists identified and reported the first two sequences of a flu subclade K globally. So at that time there was increased flu A activity globally, but this was far before the flu season had started in the U.S. So because we got those early detections that this new clade K was arriving in international travelers, the CDC was on alert for domestic cases and was able to prepare both public health and health care providers to expect to see those eventual cases. This also accelerated our CDC and public health laboratory access to samples for further viral characterization. That’s important, because that allows us to assess the potential impacts of these new emerging strains on diagnostics or therapeutics. And in this case, these data also supported research efforts on influenza antibody response.

Eric White We’re speaking with Heather Reese. She’s the lead of the Traveler-Based Genomic Surveillance program at the Centers for Disease Control and Prevention. Since we are talking about public health and you’ve reached 1 million volunteers, so there’s a lot of trust there, but since participation is voluntary, is there an anonymity to the results or how does the program balance surveillance and privacy concerns?

Heather Reese Yes, since participation is completely voluntary and anonymous, international travelers arriving at those eight U.S. airports where TGS operates have the opportunity to really opt in and provide nasal swab samples for the program. This program isn’t really designed to do case-finding. We can’t connect an individual with their test result. It’s really intended to track changes in pathogen levels at a population level. This program cannot connect a specific traveler to their test results; so the program isn’t designed for it. It’s designed to allow us to track trends in pathogens of public health concern or these emerging strains at a population level and monitor new variants, strains or mutations as they come up.

Eric White It does keep in mind of where that passenger just arrived from, I imagine though, right?

Heather Reese Absolutely. We do collect information on the participants’ travel history and that part allows us to really fill gaps in global biosurveillance data. So these pathogens and variants might be circling in different countries, regions of the world, where testing and sequencing information might be limited. And so this gives us a snapshot of what’s going on before it gets to our shores.

Eric White And just to go over who’s involved in this, what assets of the Centers for Disease Control and Prevention, and also any partnerships that you have? You said you’re at eight airports. How do you approach that, asking different airports, hey, can we come on in and swab some of your passengers?

Heather Reese Strong partnerships are key to creating a network that allows for this early and efficient disease detection. So the TGS program wouldn’t be possible without CDC subject matter expertise across various disciplines, our industry partners, both Ginkgo Biosecurity and ExWell. They’re really our implementation partners on the ground and do a lot of our laboratory testing. As well as you mentioned, those eight airports, as well is participating airlines, and of course, the public. So this program wouldn’t be possible without their continued support of the program.

Eric White Looking forward towards the future, any plans of expanding to other airports, or are you all just good with a million so far?

Heather Reese Well, we continue to collect nasal swab samples from travelers who arrive at those airports. We’re considering to understand how this program can best and most effectively and efficiently capture these trends.

Eric White Do you see any sort of specific trends, obviously during cold and flu season you’d probably see some upticks, but as far as varying between seasons and everything like that, are there kind of natural occurrences that you see flowing through, or is it kind of erratic in the results that you see? A spike here or a spike there sort of deal?

Heather Reese Several of the pathogens that we track, as you mentioned, SARS-CoV-2, RSV, and influenza A and B are seasonal. So we have those expected seasonal surges. But because we’re really tracking global circulation from those international travelers who are arriving from about 130 countries every week is what we capture, you’ll get the seasonal fluctuations in those regions of the world in addition to what we consider the classic respiratory virus season in the wintertime here. As far as emergence of new strains or variants of concern, there is no clear schedule for that. So we’re always on alert and monitoring to see if something of potential concern might be popping up.

Eric White And I don’t want to put any doomsday scenarios in anyone’s head or anything like that. But were you to see a sharp spike in a new strain of, let’s say, a new version of COVID. I mean, it was all about how quickly we could react at the beginning of the pandemic. Are there procedures in place for you all to sound the alarm bells if something does pop up?

Heather Reese Absolutely. And I think that’s where we can lean on our strong partnerships. So when we were constantly seeing these data come in — these data take between days to just a little over a week for us from sample collection to seeing those results. And so we are constantly monitoring to see if anything of potential concern pops up. We work very closely with those pathogen home programs, with those CDC scientists across the agency, as well as with other partners so that we can react quickly and understand is this new thing that popped up something that we should be concerned about or something we should just continue to keep an eye on.