There are seven subvariants of Omicron monitored by the World Health Organization (WHO): BF.7 (BA.5 + R346T mutation); BQ.1 called ‘Cerberus’ (including BQ.1.1); BA.2.75 called ‘Centaurus’; CH.1.1 called ‘Orthrus’ (BA.2.75 + mutations L452R, F486S); XBB called ‘Gryphon’ (BA.2.10.1 and recombinant BA.2.75); XBB.1.5 this ‘Kraken’ e XBF called ‘Bythos’ (BA.5.2.3 and recombinant BA.2.75.3). These subvariants, according to the WHO, have a “transmission advantage” compared to the others in circulation.
«No additional risk»
XBF is a “new entry”, which in the latest WHO report represented 1.2% of all deposited sequences (it has been identified in 46 countries, including Italy). The most common was XBB.1.5 (32.6% of sequences), followed by Omicron BA.5 and its sub-lineages (31.8%). In Italy, between January and February, the spread of CH.1.1 e XBB.1.5. “Currently available information does not suggest that XBB.1.5 presents additional public health risks compared to other Omicron-descended lineages,” the paper reads.
Present in Italy
XBF has also been identified in Italy and in the bulletin of the Higher Institute of Health of March 3 represents 4.74 percent of the sequences detected (149 cases). The first sequences of XBF were reported on July 27, 2022. The subvariant has recently been linked to an increase in infections in Australia and Sweden. For the moment, its circulation remains limited, but it is characterized by some mutations that could make it more transmissible and immunoevasive. “At the moment – underlines the WHO – there is no epidemiological evidence that the XBF sub-variant leads to an increase in cases, hospitalizations or deaths”.