New Omicron variant CH.1.1, or “Orthrus” detected in more than 60 countries including Hong Kong


31st January 2023 – (Hong Kong) COVID-19 epidemic is slowing down around the world, but the development of new virus variants is still a cause for concern. After Omicron XBB.1.5 has become the Mainstream strain in many countries, scientists have recently noticed the prevalence of another strain CH.1.1. CH.1.1, or “Orthrus”, was estimated to comprise 1.5% of U.S. cases as of Friday. Another Omicron spawn, it was named after a mythical two-headed cattle dog killed by Hercules, by Australian variant tracker Mike Honey. According to Fortune, not much is known about the relatively new strain, levels of which have been rising globally since November. Like other “high flying” COVID variants, it has the potential to be more transmissible, evade immunity from vaccine and infection, and cause more severe symptoms.

According to Global Times, the new Omicron variant CH.1.1 has been detected in over 60 countries, presents a certain degree of immune evasion ability. However, it shows no significant increase in its ability to cause disease, posing only a minimal threat to China, an expert was quoted as saying by Jiankang Shibao (Health Times) on Tuesday.

This new strain demonstrates immune escape and vaccine escape abilities, and also contains mutations of Delta variants, or has higher infectivity. CH.1.1 is currently found in Hong Kong, Taiwan, Southeast Asia, Europe and the United States. The transmission rate has been increasing since November last year, accounting for about 10% of the current global testing samples. In the report released last week, it was also included in one of the variants under monitoring (VUM). CH.1.1 was first discovered in Southeast Asia last fall. Up to now, about one-third of the infections in New Zealand belonged to this variant, and about one-quarter of the cases in Hong Kong, the United Kingdom, and Papua New Guinea were CH.1.1.

Mainland China announced 3 new infections of this variant at the beginning of the month.

The research team at Ohio State University found the CH.1.1 carries the L452R substitution previously discovered in the Delta variant.  Experts are concerned that CH.1.1’s ability to escape vaccines may make it more transmissible and pathogenic than other Omicron variants.