In partnership with the CDC, the collected samples will be sent to approved clinical laboratories for testing as a way to monitor for traces of the SARS-CoV-2 virus
Microbiologists and virologists engaged in tracing sources of viral infections will be interested to learn that the San Francisco International Airport (SFO), in partnership with the Centers for Disease Control and Prevention (CDC), has launched a clinical laboratory testing program where wastewater from airplanes will be screened to search for traces of emerging SARS-CoV-2 coronavirus variants, the virus responsible for COVID-19 infections.
SFO announced in a press release that it is “The first airport in the United States to launch a CDC program to continuously monitor airplane wastewater samples from the onsite [airline waste] triturator for variants of SARS-CoV-2,” adding, “Concentric by Ginkgo, the biosecurity and public health unit of Boston-based synthetic biology company Ginkgo Bioworks, has installed an automatic sampling device that regularly collects combined wastewater flows from international arriving flights at SFO. These samples are then sent to an approved clinical laboratory for testing.”
This is another example of how the COVID-19 pandemic triggered advances in technologies that detect infectious diseases earlier using various samples—and access to different sources of samples—that have been historically used in the field of public health.
“This program is critical for early detection and filling in many blind spots in global surveillance,” Cindy Friedman, MD, Chief of the Travelers’ Health Branch at the CDC, told Time. Clinical laboratories approved for the SFO/CDC screening program will receive the samples for testing. (Photo copyright: NAFSA.)
CDC Program That Monitors International Travelers for Disease
When SFO wastewater samples test positive for the SARS-CoV-2 virus, scientists will perform genome sequencing on the samples to identify which variant of the pathogen is present. This process takes five to seven days. The results are then reported to the CDC.
“As we know from the COVID-19 pandemic, pathogens can spread quickly across the globe, impacting travel and trade,” said Cindy Friedman, MD, Chief of the Travelers’ Health Branch of the CDC’s Division of Global Migration and Quarantine in an SFO press release. “Testing of airplane wastewater can provide early detection of new COVID-19 variants and other pathogens that can cause outbreaks and pandemics. CDC appreciates the collaboration with SFO to further enhance these efforts.”
Concentric by Ginkgo has installed an automatic device that will collect wastewater samples from various international flights upon arrival at SFO. Those samples will then be sent to a diagnostic laboratory where they will be examined for traces of known and unknown viruses, including new variants of SARS-CoV-2.
“It’s a little gross when you start thinking about it,” epidemiologist Katelyn Jetelina, PhD, a scientific consultant for the CDC, told CNN. “But these are really long flights, and we would expect the majority of people would go to the bathroom.”
Other Airports Conducting CDC Screening
The CDC’s Traveler-based Genomic Surveillance (TGS) program was introduced in 2021 to monitor international travelers entering the US for variants of the SARS-CoV-2 coronavirus. Volunteers participate by providing nasal swabs that get batched into pools at the airport. The pooled samples are then sent to Ginkgo’s lab network where they undergo polymerase chain reaction (PCR) testing. All positive samples then receive genomic sequencing.
According to the CDC website, 110,000 volunteers participated in TGS nasal swab testing between November 2021 and February of this year. During that same period, 2,700 positive pools were sequenced and the samples shared with the CDC for viral characterization.
There are currently seven airports in the US participating in the voluntary TGS initiative. In addition to SFO, the other airports in the CDC program are:
- John F. Kennedy International Airport
- Newark Liberty International Airport
- Hartsfield-Jackson Atlanta International Airport
- Los Angeles International Airport
- Seattle-Tacoma International Airport
- Washington Dulles International Airport
However, at this time, SFO is the only airport where wastewater from aircrafts is being tested for coronavirus variants.
Wastewater Best Way to Assess Infections in Community
“Biology doesn’t respect borders, and airports and other ports of entry are critical nodes for monitoring the spread of pathogens,” said Matthew McKnight, General Manager, Biosecurity, at Ginkgo Bioworks, in the SFO press release. “We are proud to partner with SFO on developing cutting-edge biosecurity technology to support public health.”
Because traces of the virus that causes COVID-19 can be detected in human fecal matter, even if symptoms are not present, wastewater sampling will continue to be an important tool in the fight against the coronavirus.
“Wastewater surveillance is really the best way to assess infections in the community because people just aren’t testing as much due to the relaxing of testing requirements and a rise in testing fatigue, among other factors,” Ashish Jha, MD, a general internist physician and White House Coronavirus Response Coordinator, told CNN.
“So, when I look at data every day on trying to assess where we are with infections, I look at wastewater data,” he added.
Clinical Laboratories a Critical Aspect of COVID-19 Surveillance
Dark Daily has covered clinical laboratory involvement in wastewater surveillance in numerous ebriefings.
In “New, Cryptic COVID-19 Lineage Found in Ohio Wastewater by Molecular Virologist Tracking Spread of SARS-CoV-2 Variants,” we reported on the discovery of a new strain of SARS-CoV-2, the coronavirus that caused the COVID-19 pandemic, in wastewater sampled in Ohio.
And in “Studies Finding Remnants of SARS-CoV-2 in Sewage Suggest COVID-19 May Not Have Originated at Wuhan Market, Some Scientists Dispute the Findings,” we covered how researchers from the Bangor University in the UK who were using PCR testing to find traces of SARS-CoV-2 in untreated wastewater had come to the conclusion that the SARS-CoV-2 coronavirus appeared in Europe long before the first reported cases in Wuhan, China. Their findings sparked controversy among many microbiologists and other scientists.
And so, since clinical laboratories will continue to be relied upon for sample testing and population health screenings, we will continue to monitor and report on advances in wastewater testing for SARS-CoV-2, as well as other infectious agents that might be added to these sampling programs.