The U.S. Centers for Disease Control and Prevention have announced new testing requirements for travelers arriving from the UK, but research by the agency’s own scientists shows that the rule may have only a small impact on the spread of the new British coronavirus strain.
© Warren Little / Getty Images
LONDON, ENGLAND – OCTOBER 20: Empty passenger waiting seats are pictured on October 20, 2020 at Heathrow Airport Terminal 5 in London, UK. The British government is under pressure to create a covid-19 test system to ease restrictions on incoming and outgoing travelers. (Photo by Warren Little / Getty Images)
As of Monday in the UK, passengers must have a negative Covid-19 test within three days of boarding a flight to the United States.
A CDC press release on Thursday welcomed the new changes.
“Today, President Trump is taking another step to protect the health of the American people,” according to the statement.
But, according to researchers on the CDC’s Covid-19 response team, testing three days before a flight may not work much – reducing the risk of spreading the virus by just 5 to 9%.
Dr. Paul Offit, an infectious disease specialist at the University of Pennsylvania, said the new test requirement “is like placing a wire fence to keep out a mosquito.”
The CDC order recognizes that “the test does not eliminate all risks”, but when combined with other measures such as self-monitoring of symptoms, masks and distance, “they can make travel safer”.
A federal official told CNN that the new order is just one layer in a multilayered approach to reduce the spread of the new variant, which appears to spread more easily than other strains of coronavirus.
In March, the CDC cut travel from the UK to foreigners, which reduced travel from the UK to the United States by 90%, from around 30,000 to 3,000 passengers a day, the official said.
In addition, the CDC has recommendations for international travelers, including taking the test one to three days before the flight and three to five days after the trip, combined with staying at home for seven days after the trip, even if the test is negative.
Covid-19 tests often do not detect recent infections, so someone can have a negative test and actually be infected because they are not releasing enough viruses to be detected.
“Testing 72 hours before a flight will leave many people lost,” said Dr. Peter Hotez, an infectious disease specialist at Baylor College of Medicine, who pointed out that the new variant appeared in the UK three months ago and is probably already U.S.
On the other hand, testing on departure day can be more effective, reducing the risk of transmission by 37 to 61%, according to the November report by CDC scientists, which is based on mathematical modeling and has not been peer-reviewed .
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