The Biden administration announced Wednesday that travelers from China, Hong Kong and Macau will be required to present negative Covid-19 tests before entering the United States, a move it says will slow the spread of the coronavirus. The requirement is effective from Jan. 5.
The Centers for Disease Control and Prevention’s announcement came amid growing concerns about a surge in cases in China and the country’s lack of transparency about the outbreak there.
The testing requirement applies to air travelers regardless of their nationality and vaccination status, CDC officials said. This applies to travelers from China who enter the US via a third country and to other destinations via the US. Italy and Japan have already imposed similar restrictions.
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 surge in the northeastern United States. The American trend is fueled Especially the fast-spreading Omicron subtype: XBB, which diffuses faster than that 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.
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.
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.
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 an explosion of cases in Beijing.
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 it has been in the US for several months, shows no signs of competing here with Omicron’s other versions.
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.
The scientists say that, at least, the variant driving the Chinese outbreak is not necessarily the one that most effectively evades immune responses. Since very few people in China have been infected with versions of Omicron, any of the Omicron subvariants that have been circulating the world recently could be more widespread.
In a population like China that has very little immunity to infections, the dominant variant is not necessarily the best at getting around those immune responses, but simply the one that flares up.
“In some ways, whatever takes off first is going to dominate,” says James Wood, an infectious disease expert at the University of New South Wales in Sydney.
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. And 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. An even newer version of that sub-variant called XBB.1.5 has been released, they said. Preliminary studies suggest that the latest version of XBB is efficient at evading existing immune responses and binding to human cells.
