An epidemic caused by the new Omicron variant CH.1.1 is unlikely in the short term, the Chinese Center for Disease Control and Prevention (China CDC) said on Tuesday.

CH.1.1, a descendant of Omicron variant BA.2.75, has shown increased immune evasion ability due to the addition of multiple mutation sites and may cause new infections, said China CDC, however, no significant increase in its ability to cause the disease has been observed.

Meanwhile, the level of neutralizing antibodies in most Chinese people remains high, which will have some cross-protection against CH.1.1.

The China CDC said there is a low possibility of a large-scale spread caused by the variant in the short term, but also cautioned that the vulnerable groups, including those who are over 65 years old, have underlying diseases, have not been vaccinated or the uninfected ones, still need to strengthen personal protection.

CH.1.1 around world

CH.1.1 first emerged in India in early July 2022, according to the Global Initiative on Sharing All Influenza Data (GISAID).

As of Monday, the sub-variant has been detected in 67 countries and regions, mainly prevalent in the UK, Denmark and Singapore. It accounted for about 25 percent of the uploaded COVID-19 sequences in the UK in the past month.

The United States has also seen a rising proportion of CH.1.1 in its coronavirus strains since last November. The variant is responsible for roughly 1.5 percent of local cases as of Friday, according to the U.S. CDC.

China first detected the variant last November in an imported case from Thailand. As of Monday, a total of 24 imported cases from 15 countries and regions of CH.1.1 and its offshoots had been detected, with no related local cases reported.

China CDC said in early January that the dominating strains in China remain to be BA.5.2 and BF.7, two sub-strains of Omicron variant BA.5.