The Centre for Health Protection (CHP) of the Department of Health announced that as of 0.00 am, one case of sub-lineage BA.2.75.2 and one case of sub-lineage XBB.1 have been identified by the Public Health Laboratory Services Branch among imported cases. Both patients are asymptomatic.

The sub-lineage XBB.1 case was first reported in Hong Kong, involving a woman in her 50s who arrived in Hong Kong from the United States on September 25.

The new Omicron subvariant BA.2.75 case also was first detected in the city, involving a 32-year-old woman who arrived from Singapore on September 23.

According to the experts, XBB is a combination of BJ.1 and BA.2.75 variants -- descendants of the earlier Omicron BA.2 sub-type, which is about 50% more contagious than BA.1.

For BA.2.75, a sub-lineage strain of Omicron subvariant BA.2, was first detected in India in early May. It’s already gained the ability to evade the immunity provided by current vaccines and can’t be neutralized by many of the antiviral drug treatments available. So far, the strain has been reported in 47 countries and in 39 U.S. states.

Hong Kong confirmed 4,874 new Covid patients reported on Monday, including 396 imported cases and ten deaths.