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Facts on Omicron XBB.1.5 variant

January 15, 2023

  • ​The XBB.1.5 strain is a mutated version of Omicron XBB, which was first detected in India in August. XBB, which is a merger of variants BJ.1 and BA.2.75, caused cases to quadruple in just one month in some nations.
  • The XBB.1.5 is a recombinant of the omicron BA.2.10.1 and BA.2.75 subvariants and was first detected in India and reached to 74 countries according to
  • It has raised concerns about another potential wave of Covid cases following the busy holiday travel season. 
  • Combined, XBB and XBB.1.5 make up 44% of cases in the USA., more than other versions of Omicron.
  • About 75% of confirmed cases are reported to be XBB.1.5 in the northeast of the USA. It appears to be spreading quickly but there’s no indication it causes more severe illness than any other Omicron virus.
  • One of the UK's largest Covid surveillance centers (Sanger Institute) shows 4% of cases in the week to December 17 were caused by XBB.1.5.
  • Scientists worry that XB.1.5 can get around the antibodies we have built up from Covid vaccines and previous infection from the many different types of Omicron that have spread since last December, including the original BA.1 and the more recent BQ.1.1 and BQ.1 subvariants. 
  • XBB.1.5 has gained mutations, including F486P, which help it to bypass Covid-fighting antibodies that were generated in response to vaccination or previous infection. Another change S486P is thought to improve its ability to bind to cells.
  • New Covid boosters from Moderna and Pfizer-BioNTech bolstered antibody responses to many subvariants of Omicron, including the XBB variant.

Last Update : 25 January 2023 11:57 PM
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