CDC allays fears over spread of CH.1.1 variant in China

China's CDC said on Tuesday that CH.1.1, one of the variants of the Omicron variant BA.2.75, will not cause widespread local transmission in China in the near future.

The agency addressed some of the concerns about the variant.

Q: What is CH.1.1?

A: CH.1.1 is a descendant of BA.2.75 with a greater immune escape. It has acquired the Delta mutation, which is also present in BA.5.3 and BA.5.1.3, among other Omicron sublineages.

Since November 2022, CH.1.1 has taken an increasing share of the new coronavirus strain prevalent in the United States. CH.1.1 was the fifth most frequent strain in the US during the fourth week of 2023, following XBB.1.5, BQ.1.1, BQ.1, and XBB variants.

Q: Is CH.1.1 more pathogenic?

A: Currently, there is no indication of an increase in the pathogenicity of CH.1.1, and further investigation is required. Before the pathogenicity of a new strain can be determined, infected cases must reach a certain number and persist for a specific amount of time after its emergence.

Q: What is the prevalence of CH.1.1 globally?

A: CH.1.1 was detected first in India on July 8, 2022. CH.1.1 and its sublineages accounted for over 6 percent of the global sequence count in the previous month. It has been found in 67 nations or regions as of January 30, 2023, and is most abundant in the United Kingdom, Denmark, and Singapore, accounting for around 25 percent of the COVID-19 sequences provided by the UK last month.

Q: What about the spread of CH.1.1 in China?

A: CH.1.1 was discovered in China for the first time in a case from Thailand to Tianjin on November 13, 2022. By January 30, 2023, 24 cases of CH.1.1 and its sublineages had been imported into China from 15 nations and regions. No local CH.1.1 transmissions have been reported.

Q: Will CH.1.1 unleash a second wave of infection?

A: Although CH.1.1 has a greater ability to evade immunity, a substantial population in China possesses high levels of neutralizing antibodies, providing protection against CH.1.1 infection. It will not produce a large outbreak at this time. Those who have never been infected with COVID-19 and those in vulnerable groups (those over 64 years old, with pre-existing medical issues, and unvaccinated) should be careful.

Q: How can people deal with CH.1.1?

A: Maintain good hygiene and protection. Do not believe online rumors.