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.
Statistics from outbreak.info, a community repository of COVID information which traces the COVID-19 epidemic showed that CH.1.1, also known as "Orthrus" a descendent of BA.2.75, has been detected in over 60 countries including New Zealand, Papua New Guinea, Cambodia and Ireland. In the US, 51 states have detected the new variant.
It emerged in Southeast Asia last fall and is now responsible for more than a quarter of infections in parts of the UK and New Zealand, according to a preprint paper released by researchers at Ohio State University.
The US Centers for Disease Control and Prevention (CDC) has been tracing the variant and estimated that it comprises 1.5 percent of US cases.
Based on current statistics, the CH.1.1 variant has a certain degree of immune evasion ability and may cause new infections, but there seems no significant increase in its ability to cause disease among the population, Zhao Wei, director of the biosafety research center of the School of Public Health, Southern Medical University, told the Health Times.
According to a report from Chinese Center for Disease Control and Prevention (China CDC) on the COVID-19 epidemic nationwide, the current prevailing strains in China are still BA.5.2 and BF.7 with no new mutant strains have been found, Zhao said.
According to Zhao, on the one hand, it shows that the border quarantine works so effectively that can prevent large-scale new mutant strains entering China from overseas.
On the other hand, the large-scale epidemic in China has just been brought under control, and the immune barrier of the population remains at a relatively high level. It can be judged that recent Omicron variants are less threatening to China.
In the recent study posted to bioRxiv preprint server, the researchers at Ohio State University found the CH.1.1 carries the L452R substitution previously discovered in the Delta variant.
According to the researchers from Ohio State University, CH.1.1 also binds well to ACE2 receptors, the site where COVID infects human cells, which means it has the potential to override—at least partially—antibody immunity from prior infection and vaccination, as well as to cause more severe disease.
It may be able to outperform other competitive Omicron strains in these arenas due to a concerning L452R mutation seen in Delta, but generally not in Omicron, the researchers said.