Covid-19: What do we know about XBB.1.5 and should we be worried?

Abstract

What do we know about XBB.1.5 and should we be worried?The XBB.1.5 omicron variant of SARS-CoV-2 has been making headlines for weeks. Elisabeth Mahase reports what we know so far Elisabeth MahaseWhat is XBB.1.5? XBB.1.5 is yet another omicron subvariant, and follows on from XBB and XBB.1. Scientists have nicknamed it "kraken" to distinguish it from the "variant soup" we are all navigating three years into the pandemic. 1 The X signifies that these subvariants came about through a recombination of two or more sublineages-in this case BA.2.10.1 and BA.2.75. 2 According to UCL Genetics Institute director Francois Balloux, a professor of computational systems biology, XBB.1.5 differs from XBB.1 through the addition of a F486P mutation in the spike protein."This mutation makes it slightly less immune evasive than its XBB.1 ancestor but more infectious, probably because it increases binding affinity to the human cell receptor ACE-2," he said.

Ancestral SARS‐CoV‐2 and Omicron BA.5‐specific neutralizing antibody and T‐cell responses after Omicron bivalent booster vaccination in previously infected and infection‐naive individuals

“…These findings can be explained by the more than 30 substitutions in the spike protein, which make Omicron highly transmissible and very efficient at immune evasion 9,10 . Moreover, these characteristics improved even further in each Omicron subvariant, including the previously dominant BA.1, BA.2, BA.4, and BA.5, 1,10 and the most recent dominant subvariants XBB and XBB1.5 2,11 …”

“…9,10 Moreover, these characteristics improved even further in each Omicron subvariant, including the previously dominant BA.1, BA.2, BA.4, and BA.5, 1,10 and the most recent dominant subvariants XBB and XBB1.5. 2,11 The continuing emergence of new Omicron subvariants and concerns about waning immunity has led to the development of bivalent booster vaccines. From September 2022, these bivalent vaccines, containing spike-encoding mRNA of both the ancestral strain and Omicron BA.1, were first administered.…”

Rapid screening methods for universal binding peptide aptamers against SARS-CoV-2 variant spikes, including omicron variants, and their application to diagnostic and therapeutic agents.

“…The Omicron variant of the highly infectious SARS-COV-2 mutant, which emerged at the end of 2021, began as BA.1 and has mutated to BA.2 and BA.5. In January 2023, a BQ.1.1 strain derived from BA.5 and an XBB strain derived from BA.2 have emerged, although BA.5 is still the mainstream strain(1-27) , (28)(29)(30)(31).…”

Ancestral SARS-CoV-2 and Omicron BA.5-specific neutralizing antibody and T cell responses after Omicron bivalent booster vaccination in previously infected and infection-naive individuals

“…9,10 Moreover, these characteristics improved even further in each Omicron subvariant, including the previously dominant BA.1, BA.2, BA.4, and BA.5, 1,10 and the most recent dominant subvariants XBB and XBB1.5. 2,11 The continuing emergence of new Omicron subvariants and concerns about waning immunity have led to the development of bivalent booster vaccines. From September 2022, these bivalent vaccines, containing spike-encoding mRNA of both the ancestral strain and Omicron BA.1, were first administered.…”