SFO launches airplane wastewater testing to track emerging COVID-19 variants
San Francisco International Airport has launched a program with the US Centers for Disease Control and Prevention to test wastewater from airplanes for traces of emerging coronavirus variants.
Traces of the virus that causes COVID-19 can be detected in people's feces when they are infected, even if they don't have symptoms.
The airport announced Tuesday that the CDC's partner Concentric by Ginkgo, the biosecurity and public health unit of Boston-based synthetic biology company Ginkgo Bioworks, has installed an automatic device that will regularly collect wastewater samples from various international flights arriving at SFO.
Those combined samples of wastewater then will be sent to laboratories for testing.
"As we know from the COVID-19 pandemic, pathogens can spread quickly across the globe, impacting travel and trade," Dr. Cindy Friedman, chief of the CDC's Travelers' Health Branch, said in a news release Tuesday. "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."
SFO will be the first airport to launch this pilot program with the CDC, Airport Director Ivar Satero said in the announcement.
The airport also has been involved in supplying wastewater samples to the University of California, San Francisco Medical Center to help identify emerging coronavirus variants, but those samples were taken from the airport's wastewater treatment plant.
Testing aircraft wastewater involves collecting sewage from individual commercial passenger planes.
"You can pull it off the airplane in under two minutes, quickly put it into a lab network, which we manage all of that," Matt McKnight, general manager at Ginkgo Bioworks, told CNN in January.
Once those wastewater samples arrive at a diagnostic lab for testing, scientists scan them for traces of known or unknown viruses, such as emerging variants of SARS-CoV-2, the coronavirus that causes COVID-19.
When samples test positive for the virus, scientists conduct genome sequencing -- which usually takes about five to seven days -- to identify exactly which variant that virus is. Then, scientists may analyze their results and submit their findings to the CDC.
Monitoring sewage for traces of coronavirus variants is a "validated" scientific process -- no longer in its pilot phase -- and airplanes are a logical next step, McKnight said.
The United States' declaration of a public health emergency due to COVID-19 is set to end Thursday, but White House COVID-19 Response Coordinator Dr. Ashish Jha said that it will continue to be important to monitor wastewater for emerging variants.
"If you think about what data is really valuable today, wastewater surveillance is really the best way to assess infections in the community," Jha said, noting that test positivity no longer presents as fulsome of a picture "because people just aren't testing as much" due to the relaxing of testing requirements and a rise in testing fatigue, among other factors.
"So, when I look at data every day on trying to assess where we are with infections, I look at wastewater data. That continues. That will continue, and wastewater now covers the majority of Americans," he said. "When I'm trying to assess severity of illness ... it's hospitalizations and deaths."