Fearing that a surge of coronavirus infections in Beijing could create a new and dangerous variant, the Biden administration announced on Wednesday that travelers from China, including Hong Kong and Macau, must provide negative Covid-19 tests before entering the United States. In the states.
The requirement will go into effect on January 5, the Centers for Disease Control and Prevention said in the announcement. Officials at the agency are deeply concerned about China’s lack of transparency about the outbreak — and, in particular, its failure to monitor and sequence variants and subtypes circulating within its borders.
The testing requirement applies to air travelers regardless of their nationality and vaccination status, CDC officials said. This also applies to travelers from China entering the US through a third country or connecting to other destinations via the US. Italy and Japan have already imposed similar restrictions, and India has mandated Covid-19 test reports and random screening at airports for passengers arriving from China, Japan, South Korea, Hong Kong and Thailand.
But President Donald J. As they did when Trump imposed pandemic travel limits, some experts question whether the testing requirement will do any good — especially as cases continue to rise in some parts of the United States. In the Northeast, scientists say the spread of the virus is fueled An omicron subtypeXBB, which spreads faster than the one associated with the dominant variant in Beijing.
“I understand why it has to be done politically, but the bottom line is that it’s a false sense of security that we’re actually slowing the spread,” said Michael D. said Osterholm, director of the Center for Infectious Disease Research and Policy. University of Minnesota.
China’s Covid outbreak has worsened in recent days, with local governments reporting Hundreds of thousands of infections per day. Videos obtained by The New York Times program Sick patients are thronging the hospital premises. But it is difficult to monitor the situation in real time because China Trusted doesn’t publish covid data.
The CDC announced Wednesday that it is expanding a voluntary genetic surveillance program that looks for new strains in anonymous swabs taken from international travelers at major U.S. airports, including Los Angeles and Seattle.
Understand the situation in China
The Communist Party has set aside a restrictive “zero Covid” policy, setting off mass protests that have been a rare challenge to the Communist leadership.
Some experts worry that instead of encouraging more openness from China, the policy will make the Chinese even less attractive.
“The most important strategy now is to improve our political and diplomatic engagement with China,” said Emory University epidemiologist Dr. Carlos Del Rio, who said he fears the Biden administration’s new policy will work “in the opposite direction.”
But Jennifer Nasso, director of the Epidemiology Center at Brown University School of Public Health, said the administration had no choice.
“I think they’re trying to put some pressure on China to uphold its international obligations,” he said, adding that the “contract of agreement” that calls on countries to share data on an epidemic “will only work if countries call.” Bad behavior.”
After three years of insisting on the “Zero Covid” policy, China created it A sudden turn It scrapped the policy in early December after mass protests over the lockdowns threatened the ruling Communist Party. Since then, there has been a dramatic rise in the number of cases in Beijing.
A major concern among public health officials is that the Chinese population has low natural immunity, allowing the virus to spread rapidly. The rapid spread creates new opportunities for the virus to evolve, which poses the risk of new variants emerging and spreading to other parts of the world.
That doesn’t mean China’s most dangerous variant will emerge anytime soon, scientists say. In the past year, people in the United States have been hit by waves of Omicron subtypes. But because people in China are essentially walled off from those versions of the virus, any of them could get there, the scientists said.
“In some sense, whatever took off first will dominate there,” said James Wood, an infectious disease expert at the University of New South Wales in Sydney.
While some past variants are believed to have emerged when the virus mutated during long epidemics in people with compromised immune systems, the extent of transmission at a given location does not itself determine the likelihood of new variants evolving.
“There’s an argument that the more people are infected, the more opportunities there are for mutation and the development of new variants,” says Jeffrey Shaman, an infectious-disease modeler at Columbia University. New variants mainly develop from person to person or within individuals experiencing extended infections.”
Scientists in Hong Kong have reported that the omicron subvariant Known as BF.7 for the Beijing explosion. That variant is a sub-series of the BA.5, which until recently dominated the US. But the BF.7, while in the US for several months, shows no signs of outpacing other versions of the Omicron in the country.
The CDC estimates that BF.7 was 4 percent at the end of December, and has been low since November. Other Omicron subtypes, including XBB, which scientists believe are more adept at evading existing immune responses, are now more common in the United States.
In the United States, the CDC estimated last week that the XBB subtype has grown to nearly one-fifth of the country, up from just 3 percent a month ago.
XBB is spreading particularly quickly across the northeastern United States, scientists said, accounting for more than half of new infections there. It appears to have an advantage over the BQ.1 Omicron sub-variants that have recently dominated the US, the scientists said.
Scientists are in the early stages of studying the XBB subtype. They said an even newer version of that sub-variant, called XBB.1.5, is out. Early studies suggest the new version is more efficient at evading existing immune responses and binding to human cells.
The scientists said it will be important to scan for new variants, especially in the coming months, when more people in China have developed immunity from previous infections and the virus is under greater pressure to evolve there.
Dr Wood of the University of New South Wales said: “It would be good to summarize what kind of variation China is seeing. “Otherwise, eventually, it will be picked up in genetic surveillance in Europe or America or places where people travel.”
However, he said, at this time, China does not pose a great risk of creating a new variant.
“We’ve had the highest number of infections internationally,” he said. “That’s more infections than in China alone.”
Emily Andes And Karan Deep Singh Contributed report.