Experts in Japan have expressed caution about the emergence of a new Omicron strain of the coronavirus, the XBB.1.5 subvariant.

Experts tasked with assessing the coronavirus situation in Tokyo said at a meeting on Thursday that 15 cases of XBB.1.5 have been confirmed in the capital since the subvariant was detected for the first time on December 1.

A panel of experts for the health ministry said the World Health Organization and others point to the possibility that XBB.1.5 may be contributing to increases in the number of cases. But the experts said there is no epidemiological or clinical evidence on the transmissibility and severity of XBB.1.5. They stressed the importance of analyzing the situations abroad and continuing monitoring through genome analysis.

Tokyo Medical University Hospital Professor Hamada Atsuo says XBB.1.5 is believed to be not only more capable of evading immunity but is also more infectious. He added he is concerned that this subvariant could prolong the current eighth wave of the pandemic.