US Flights from China May Use Wastewater Testing to Detect New COVID Variants

A number of North American airline operators might start using wastewater testing to detect new COVID variants that may be emerging in China, according to Reuters. The Centers for Disease Control and Prevention (CDC) is considering sampling wastewater taken from international aircraft in a bid to slow the entry of any new variants into the United States. It’s considered a better solution than new travel restrictions, such as mandatory negative COVID tests for travellers from China, as such measures have so far had exceedingly little impact on slowing the spread of COVID. An infectious disease expert at the University of Minnesota, Dr. Michael Osterholm gave Reuters his view that travels restrictions are little more than a public relations exercise: “I think each government feels like they will be accused of not doing enough to protect their citizens if they don't do these."  

Furthermore, the CDC is expanding its voluntary genomic sequencing program at airports, adding sites in Seattle and Los Angeles, bringing the total number of airports gathering information from positive tests to seven. However, some experts say this is still too few, that it may not provide a meaningful sample size – and that’s where testing wastewater from planes comes in. Such samples would offer a clearer picture of how the virus is mutating, given China's lack of data transparency – Director of the Scripps Research Translational Institute in La Jolla, California, Dr. Eric Topol told Reuters that he believed it to be “a very good tactic” in light of this opacity

But Chinese officials have called such criticisms groundless and are optimistic about the risk of new variants, stating that any mutations may be more infectious but will most likely be less severe. However, doubts over official Chinese data have prompted many places, including the United States, Italy, and Japan, to impose new testing rules on Chinese visitors.  

In virtual correspondence with Reuters, a spokeswoman for the CDC, Kristen Nordlund, said: "Previous COVID-19 wastewater surveillance has shown to be a valuable tool and airplane wastewater surveillance could potentially be an option.” It’s an idea that’s been receiving attention for a year or so, as new research began to cast doubt on the usual protections. Back in the days of the Omicron variant, researchers at a French laboratory found that airplane wastewater testing completely undermined the assumption that negative tests protected countries from new variants of COVID-19, after finding Omicron in the wastewater of two flights from Ethiopia to France that had not admitted any passengers with a positive test. Similarly, an American study reported that wastewater testing in San Diegan communities was a fortnight ahead of nasal swabs in spotting the Alpha, Delta, Epsilon, and Omicron variants.  

Echoing these findings, David Dowdy, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, said: "Genomic sequencing will give us a much clearer picture of what is happening with the virus globally, and in real-time, rather than relying on reports from other countries that may be delayed or incomplete." Without a robust wastewater testing infrastructure, then, the rest of the world may be paralysed by fresh waves of the virus emanating from China. 

Clearly, wastewater testing has already proven to be a valuable tool in tracking the spread of COVID and detecting new variants. There have been a number of successful trials: for example, in Australia, wastewater testing was used to detect the Delta variant in Victoria before it was identified in any human cases; and in the Netherlands, wastewater testing helped detect the Delta variant in the Amsterdam area before it showed up on nasal swabs.  

It's clear, then, that wastewater testing has a number of advantages over traditional methods of tracking the spread of COVID-19, especially in the detection of new variants. First off, it is non-invasive; it can be done quickly and cheaply. It provides a more comprehensive picture of the prevalence of the virus in a community, as it can detect cases in people who may be asymptomatic or who have not been tested. Most importantly, of course. wastewater testing can detect the presence of the virus before it starts spreading in a community, allowing authorities to implement measures to prevent its spread.  

While wastewater testing might not be able to replace traditional methods, it can might prove to be an essential too in the ongoing fight against the virus. By using wastewater testing, flight operators and health officials can get a better understanding of the prevalence of COVID and its variants in different communities, enabling them to take steps towards slowing the spread. With all of these benefits up for grabs, there's no time to waste in setting up a robust wastewater testing infrastructure for international flights.