On May 16, CDC Weekly Report (English) reported the first imported case of NIV "BA.2.12.1" confirmed to be infected with the subtype "Omicron" strain in China. It is reported that BA.2.12.1 is the offspring of the variant BA.2 of the New Coronavirus Omicron subtype. Compared with other Omicron subtype strains, BA.2.12.1 has a stronger immune escape ability, and some studies have shown that BA.2.12.1 has a 23% to 27% faster transmission rate than BA.2. The work on rapid nucleic acid testing of New Crown has a long way to go.
A series of mutant strains of Neocrown Omicron, BA.1, BA.2, BA.2.12.1, BA.4 and BA.5, are causing new outbreak fluctuations one after another around the world. Next, let's talk about why new coronaviruses mutate.
New coronaviruses are single-stranded RNA viruses characterized by a large RNA genome open reading frame ORF1ab and S, N, and E genes; the outermost layer of the virus has an envelope structure that includes the stinger protein
(S), the small envelope protein (E), and the membrane protein (M).
The ORF1ab and N genes are currently the most commonly used targets in rapid nucleic acid testing of new coronaviruses.
Viruses tend to mutate during transmission, but the rate and frequency of mutation varies from virus to virus. Because viruses need to enter the host's cells to replicate, this process is more prone to replication errors than in other organisms. In addition, new coronaviruses use viral polymerase to help replicate and use RNA polymerase to replicate and transcribe their genomes, but RNA polymerase does not have nuclease correction activity, and the rate of nucleotide mismatches during replication of the new coronavirus genome is relatively high.
As a result of nucleotide mismatches, it leads to constant changes in the infectivity, pathogenicity, and lethality of neo-coronaviruses, and the emergence of variant strains with different characteristics. Based on this condition, together with the selection of environmental factors, the new crown mutant strains that are more suitable for transmission will survive and start to spread. This is the reason why new coronavirus mutant strains keep appearing.
As NIV continues to mutate, protection and timely screening with the Nucleic Acid Rapid Test is a prerequisite for early detection and tracking of mutated strains.
The Nucleic Acid Rapid Test identifies the ORF1ab and N genes of the virus and then matches the genetic code of previously identified strains by gene sequencing to determine whether the strain is already endemic or a new mutant.
When the comparison results show that the strain is already endemic, it is traced; if it is a newly mutated strain, it is reported to the database for global epidemiologists and virologists to study and analyze its virulence, transmission rate, etc.
