The United States is considering testing sewage from planes on international routes to detect possible new variants of COVID-19 as infections in China rise. According to British health experts, 9,000 people die of this disease every day in China, The Guardian reports.

A proposal by the U.S. Centers for Disease Control and Prevention to test sewage would provide a better solution for tracking the virus and slowing its entry into the U.S. than new travel restrictions announced this week, three infectious disease experts said.

The US and other countries have announced that people traveling from China will be required to have negative tests for COVID.

The claims came after UK-based Airfinity revealed that around 9,000 people are dying of COVID-19 every day in China, double the estimate a week ago.

COVID infections began to spread in China in November, intensifying this month after Beijing abandoned its policy of zero COVID infections, including regular testing of the population and publication of data on asymptomatic cases.

The total number of deaths in China since Dec. 1 has likely reached 100,000, with the total number of infections at 18.6 million, Airfinity said on Thursday. The firm explained that it used a model based on data from China’s provinces before changing the way cases were reported.

Airfinity expects the number of COVID infections in China to reach its first peak on January 13, with 3.7 million cases per day.

The data contrasts with figures reported by Chinese authorities of several thousand daily cases after a nationwide network of PCR testing centers was largely dismantled and authorities shifted from preventing infections to treating them.

The European Union’s health agency said on Thursday that imposing mandatory COVID tests on people traveling from China via EU countries is currently “unjustified”, citing “higher population immunity” and the fact that that the variants now circulating in China came earlier and were superseded.

However, the head of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus, in a series of messages on Twitter, repeated the call for China to be more communicative with detailed data on the country’s pandemic situation.

“In the absence of full information from China, it is clear that some countries around the world are acting in ways they believe could protect the public,” he wrote.

Airfinity expects the number of deaths to peak on January 23 at around 25,000 each day, bringing the total to 584,000 since December. Since December 7, when China dramatically reversed its stance, authorities have officially reported only ten deaths from COVID.

According to Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, travel restrictions such as mandatory testing have so far failed to significantly slow the spread of COVID and work more visually.

“They seem important from a political point of view. “I think every government feels that they will be accused of not doing enough to protect citizens if they don’t take these measures,” he said.

This week, the US expanded its voluntary genomic sequencing program at airports, including in Seattle and Los Angeles. Thus, the number of airports collecting information on positive tests has reached seven.

But experts say this may not provide a significant test batch.

A better solution would be to test water residue from airplanes, which would give a clearer picture of how the virus is mutating, given the lack of transparency in China, said Dr. Eric Topol, a genomics expert and director of the Scripps Translational Institute. Research in La Jolla, California.

Sampling sewage from planes coming from China “would be a very good tactic,” Topol said, adding that it was important for the U.S. to improve its monitoring tactics “because China does not want to share its genomic data.”

China has said these criticisms of its COVID data are unfounded and played down the risk of new variants emerging, saying it expects the mutations to be more contagious but less severe. However, doubts about official Chinese data have led many countries, including Italy, Japan and the US, to introduce new testing rules for visitors from China, while Beijing has lifted travel restrictions.

Testing sewage from airplanes is one option the Centers for Disease Control and Prevention is considering to help slow the introduction of new strains into the U.S. from other countries, agency spokeswoman Kristen Nordlund said.

“Surveillance for COVID-19 in wastewater has previously shown to be a valuable tool, and monitoring wastewater from aircraft may be one option,” she said.

French researchers announced in July that testing of aircraft sewage showed that mandatory negative tests for COVID before international flights do not protect countries from the spread of new variants. They found the Omicron variant in the sewage of two commercial airliners flying from Ethiopia to France in December 2021, even though passengers were required to be tested for COVID before boarding.