XBB.1.5 strain, January 4, 2023, Suqian, Jiangsu, China.
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The XBB.1.5 omicron subvariant that currently dominates the United States is the most contagious version of Covid-19 to date, nevertheless it doesn’t appear to make people sicker, according to the World Health Organization.
Maria Van Kerkhove, WHO’s COVID-19 technical manager, said global health officials are concerned about the rate of spread of the subvariant in the Northeastern United States. The number of individuals infected with XBB.1.5 doubles in the US roughly every two weeks, making it the most typical variant circulating in the country.
“This is the most transmission minor variant that has been detected to date,” Van Kerkhove told reporters at a press conference in Geneva on Wednesday. “The explanation for this is the mutations which might be present in this omicron subvariant, allowing this virus to adhere to the cell and simply replicate.”
To this point it has been detected in 29 countries, nevertheless it could possibly be much more widespread, Van Kerkhove said. She said tracking Covid variants has turn into difficult as genome sequencing is declining globally.
The WHO doesn’t yet have any data on the severity of XBB.1.5, but right now there is no indication that individuals are sicker than previous versions of omicron, Van Kerkhove said. She said a WHO advisory group that tracks Covid variants is carrying out a risk assessment on XBB.1.5 which it would publish in the coming days.
“The more this virus circulates, the more opportunities it would have to change,” Van Kerkhove said. “We expect more waves of infections around the world, but that does not necessarily translate to more deaths as our countermeasures proceed to work.”
The researchers say XBB.1.5 is about pretty much as good at avoiding antibodies from vaccines and infections as its relatives XBB and XBB.1, which were two of the most immune-evading subvariants to date. But XBB.1.5 has a mutation that makes it bind more tightly to cells, giving it a growth advantage.
As XBB.1.5 spreads rapidly across the United States, China is battling a surge in cases and hospitalizations after abandoning its zero-COVID-19 policy in response to civil unrest late last 12 months. US and global health officials said Beijing was not sharing enough growth data with the international community.
“We proceed to ask China for faster, regular and reliable data on hospitalizations and deaths, in addition to more comprehensive real-time viral sequencing,” WHO Director-General Tedros Adhanom Ghebreyesus told reporters in Geneva on Wednesday.
An increasing number of countries, including the United States, are requiring airline passengers from China to test negative for Covid before boarding a flight. China’s foreign ministry said such measures had no scientific basis and accused governments of manipulating Covid for political purposes. But the WHO director-general said the requirements are comprehensible given the limited data coming in from China.
“With such a high circulation in China and the lack of complete data, it’s comprehensible that some countries are taking steps they imagine will protect their very own residents,” Tedros said on Wednesday.
The Beijing Center for Disease Control and Prevention released WHO data on Tuesday, identifying subtypes BA.5, BA.5.2 and BF.7, which account for about 98% of all infections in the country. But Van Kerkhove said China didn’t share enough sequencing data from across the vast country.
“It is not nearly knowing what variants are circulating,” Van Kerkhove said. “We want a worldwide community to evaluate them, take a look at them mutate by mutation to determine if any of them are recent variants circulating in China, but in addition around the world.”