Omicron's new variant "two-headed dog" CH.1.1 is present in Hong Kong and Taiwan or is more contagious and can cause severe illness

Novel coronavirus infection (COVID-19, formerly known as novel coronavirus pneumonia) continues to spread globally. In addition to the most contagious Omicron subtype variant strain XBB.1.5 so far, a new Omicron variant CH.1.1 has recently spread to Case numbers are on the rise in at least 72 countries.

In Hong Kong, CH.1.1 infection accounts for about 26% of the new cases, which has aroused concern.

What is CH.1.1?

Omicron has many variants, such as the mutant virus strain XBB discovered in India in August 2022, and the first sub-variant XBB.1.5 discovered in New York.

CH.1.1 is one of the variants of the Omicron variant BA.2.75, which has spread globally since November 2022.

Australian epidemiologist Mike Honey named CH.1.1 "Orthrus" after a two-headed dog in Greek mythology.

New crown pneumonia epidemic in Japan: The picture shows pedestrians walking on the road next to Shinjuku Station in Tokyo on August 14, 2021.

(Reuters)

Is the spread/lethal power stronger?

Researchers from Ohio State University stated that although CH.1.1 is not a direct relative of the XBB.1.5 variant, nor is it a variant formed by the recombination of Delta and Omicron, it has shown a phenomenon of convergent evolution, with rare features of other Omicron variants. The L452R mutation binds well to the ACE2 receptor at the site of human cells infected by the new coronavirus, or it is easier to spread, avoiding vaccination and immune protection after infection, and causing more serious diseases.

According to a report by the University of Basel in Switzerland, CH.1.1 is highly transmissible, with the level of transmission doubling approximately every two weeks.

New crown pneumonia epidemic in South Korea: On January 12, 2023, a Chinese family went to the new crown virus testing center after arriving at Incheon International Airport in South Korea.

(Reuters)

In which countries is CH.1.1 prevalent?

Data from the outbreak.info website shows that since November 2022, the prevalence of CH.1.1 has risen sharply and now accounts for about 10% of daily sequencing samples worldwide.

In the past 60 days, CH.1.1 infections accounted for 36% of new cases in New Zealand, 25% in Papua New Guinea, and 19% in Cambodia.

In Ireland and the United Kingdom, they accounted for 17% and 12% respectively.

130 CH.1.1 cases have been detected in Hong Kong, accounting for about 26% of the new cases.

COVID-19 outbreak in China: A nurse prepares the vaccine for a man as the German embassy starts rolling out the Fubitai vaccination service for German expatriates at a hospital in Beijing, China, January 5, 2023.

(Reuters)

What do the experts think?

Researchers at Ohio State University stated that the protection of the original new crown vaccine is weakening, recommending that the public be vaccinated with the Omicron bivalent vaccine, but cautioned that the protection of the bivalent vaccine against CH.1.1 is not as strong as against variants such as XBB and BQ.1.1.

At present, experts still do not have a deep understanding of CH.1.1, and it remains to be seen whether it will cause a strong epidemic.

Dr. Michael Osterholm (Michael Osterholm), director of the Center for Infectious Disease Research and Policy at the University of Minnesota, cited the XBB.1.5 threat to the United States as an example, saying, "I don't think we really know which variants need attention. , which ones are unnecessary.”

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