Gilnature | stocks | beautiful pictures
The Covid omicron XBB.1.5 variant is rapidly gaining popularity in the United States because it has a high ability to evade immunity and appears to be more effective at binding to cells than other strains, the scientists say. related sub-variants.
XBB.1.5 now accounts for about 41% of new cases nationwide in the United States, the incidence of which nearly doubled in the past week, according to data released Friday by the Centers for Disease Control and Prevention. . The sub-variant has more than doubled in rate of cases each week through December 24. In the last week, it has nearly doubled from a prevalence rate of 21.7%.
Scientists and public health officials have been closely monitoring the XBB sub-variant strain for months because these strains have many mutations that could make Covid-19 vaccines, including omicron boosters, less effective and cause even more breakthrough infections.
XBB was first identified in India in August. It quickly prevailed there, as well as in Singapore. Since then, it has evolved into a family of sub-variants that include XBB.1 and XBB.1.5.
Andrew Pekosz, a virologist at Johns Hopkins University, says XBB.1.5 is different from members of its family because it has an extra mutation that makes it better bind to cells.
“The virus needs to bind tightly to cells to get in more efficiently, and that could help the virus infect humans a little bit more effectively,” Pekosz said.
Yunlong Richard Cao, a scientist and assistant professor at Peking University, published data on Twitter on Tuesday showing that XBB.1.5 doesn’t just evade protective antibodies as effectively as the XBB variant. 1, which has a high ability to evade immunity, but also binds better to the cell through an important receptor.
Scientists at Columbia University, in a study published earlier this month in the journal Cellwarned that the proliferation of sub-variants such as XBB could “further reduce the effectiveness of the current COVID-19 vaccine and lead to an increase in infections and re-infections.”
The XBB sub-variants are also resistant to Evusheld, a mixture of antibodies that many people with weakened immune systems rely on for protection against Covid infections because they don’t have a strong reaction to the vaccine.
Scientists have described the XBB sub-variants’ resistance to vaccination and infection-induced antibodies as “alarming”. The scientists found that the XBB sub-variants were even more effective at evading protection from omicron boosters than the BQ sub-variants, which also had high immunity-evading abilities. .
Dr. David Ho, an author of the Columbia study, agreed with other scientists that XBB.1.5 may have a growth advantage because it binds to cells better than its XBB relative. Ho also reported that XBB.1.5 is nearly as immune-evading as XBB and XBB.1, two of the sub-variants with the highest resistance to infection- and immunization-protecting antibodies to date. .
Dr Anthony Fauci, who is leaving his role as chief medical adviser to the White House, has previously said that XBB sub-variants reduce the protection that boosters offer against infection “folding” many times”.
“You can expect some protection, but not optimal protection,” Fauci told reporters during a White House press conference in November.
Fauci said he was encouraged by the case of Singapore, where the number of XBB infections increased sharply but the number of hospitalizations did not increase at the same rate. Pekosz said XBB.1.5, combined with holiday travel, could lead to an increase in cases in the US. However, he said the boosters appear to be preventing serious illness.
“It appears that vaccines, bivalent boosters are providing continued protection against hospitalization with these variants,” Pekosz said. “It really highlights the need to strengthen especially vulnerable populations to continue to protect from severe disease with these new variants.”
Health officials in the US have repeatedly urged the elderly in particular to make sure they updated on their vaccines and treated with the antiretroviral drug Paxlovid if they have a severe infection.
