At present, a "new player" of COVID-19 appears in the United States. It is called CH.1.1 The Omichronya variant of Bacillus subtilis belongs to a branch of the mainstream strain BA. 275.
CH.1.1 was named "Orthus" by Mike Honey, an Australian virus expert. Research shows that compared with other COVID-19 subtypes, it may be more infectious and immune evasive, and may lead to more serious diseases.
According to the data of the United States Centers for Disease Control and Prevention (CDC), as of Saturday (28th) local time, CH.1.1 accounted for 1.5% of the cases in the United States, ranking fifth.
Source: CDC
From the data, the Omikjunya variant XBB. 1.5 has spread rapidly in the United States, replacing BQ. 1.1 as the number one COVID-19 variant in the United States, accounting for 61.3% of the total cases.
Increased infection level
Little is known about this relatively new variety. In fact, since November last year, CH.1.1 has been spreading around the world, and the level of infection has been rising.
According to the data of COVID-19 information resource database website outbreak.info, since last November, the spread rate of CH.1.1 has risen sharply, accounting for about 10% of the global daily test samples.
A preprinted paper released by researchers at Ohio State University last week said that CH.1.1 appeared in Southeast Asia last autumn. Now, about one-third of infections in parts of New Zealand are caused by CH.1.1, and about one-quarter in the United Kingdom, Hong Kong, China and Papua New Guinea.
A report from the UK Health and Safety Agency (UKHSA) this week shows that CH. 1.1 may have accounted for 23% of all new COVID-19 cases in England, and may account for 100% of new cases in some regions.
Awesome mutation
The preprinted paper pointed out that CH.1.1 found a mutation called L452R in S protein. This mutation is usually not seen in the Omixon variant, but has appeared in the Delta strain, which is worrying.
This also means that CH.1.1 may be more infectious than other Omixon strains.
In addition, it was also mentioned in the paper that CH. 1.1 can also bind well to the ACE2 receptor, which is the receptor that mediates the entry of COVID-19 into host cells.
This indicates that the virus may cover some antibodies produced by previous infection or vaccination, resulting in stronger immune escape and more serious diseases.
The researchers conducted relevant experiments on the immune escape ability of CH.1.1. The serum of 14 medical and nursing personnel were sampled in the experiment (these medical and nursing personnel received 2 to 4 doses of original vaccine and Omicotron booster injection). Through testing the neutralization effect of the serum and CH.1.1, it was found that the antibody against CH.1.1 produced in the serum was 17 times less than that against BA. 4 and BA. 5.
According to previous research by Liu Shanxi, a Chinese virologist at Ohio State University and academician of the American Academy of Microbiology, CH.1.1 almost completely escaped the neutralizing antibody induced by three doses of mRNA vaccine stimulation, but the neutralizing antibody produced by the bivalent vaccine booster injection can also play a certain role in neutralizing.
CH.1.1 Worthy of attention
Cornelius Romer, a computational biologist at the University of Basel, Switzerland, pointed out in a report last week that CH.1.1 is worthy of attention. It is highly transmissible as XBB.1.5, and the infection level will double about every two weeks.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota, said, "I don't think we really realize which mutations are worth paying attention to and which are not."
Osterholm pointed out that as far as the COVID-19 epidemic in the United States is concerned, the XBB. 1.5 variant looks like a very serious challenge at the beginning. However, since the virus has gained a dominant position in the northeast, its rise rate in other regions is not as fast as expected.
He added, "We have seen such situations before: seemingly challenging variants are not real challenges."
The World Health Organization (WHO) showed in a report on Wednesday that the CH.1.1 virus variant is one of the viruses monitored by WHO.