Popular Science: Will the "Invisible Version" of Omi keron replace the original version of the strain?

Beijing, 27 Jan (Xinhua) -- In recent weeks, the number of subtypes of the variant strain BA.2 of the Aomi Kerong strain reported by many countries has gradually increased. Will it replace the original Opmiqueron strain and sweep the globe?

The genetic lineage name of the Omiljung strain is B.1.1.529, and this variant strain was first identified in South Africa on 9 November 2021. On November 26 of the same year, the World Health Organization listed B.1.1.529 as a "needing to watch" variant and named it after the Greek letter "Omikron" (Ο).

According to the WHO website, the Omiljung strain includes the B.1.1.529 lineage and its descendants, BA.1.1, BA.2 and BA.3. So far, BA.1 infection cases account for the vast majority of global Opmi kerong infection cases, and the evidence that the "attention- needs" of the Aomi kerong strain is based on the genetic sequence of BA.1. However, the number of cases of INFECTION with the BA.2 strain with multiple different mutations in the BA.1 genome is gradually increasing in many countries.

According to Pango, an international public platform for classifying and naming the genetic lineage of the new coronavirus, the ba.2 strain genome was first discovered in a sample submitted to the Influenza Data Sharing Global Initiative platform on November 27, 2021, which was collected from South Africa's Howten Province on November 17, 2021.

According to the report released by WHO on the 21st, the proportion of BA.2 strain infections in India, South Africa, the United Kingdom, Denmark and other countries is increasing. According to foreign media reports, since November 17, 2021, about 40 countries and regions around the world have submitted nearly 15,000 BA.2 strain genome sequences to the Influenza Data Sharing Global Initiative platform.

The communiqué issued by the Danish National Serum Institute on the 20th said that the BA.2 strain is rapidly replacing the BA.1 strain in the country. In the last week of 2021, BA.2 strain infections accounted for 20% of all confirmed COVID-19 cases in Denmark, and by the second week of 2022 this proportion has risen to 45%.

According to a statement released by the British Health Safety Agency on the 21st, the BA.2 strain has been identified by the Bureau as a "variant strain under investigation (VUI)". As of the 21st, the UK has confirmed more than 400 cases of BA.2 strain infection through whole genome sequencing. The earliest cases detected in the country to date date back to 6 December 2021. BA.1 remains the main strain circulating in the UK, with a currently low proportion of CASEs of BA.2 infection.

Characteristics such as ba.2's ability to propagate are being studied and analyzed, and it is still unclear. According to WHO, the vast majority of Theomilon strain gene sequences carry a mutation with a missing segment of the spike protein, and screening for this specific mutation can quickly distinguish Omiljung infection from other variants of the new coronavirus strain infection. However, the BA.2 genome did not have this gene segment missing, so it could not be detected in the routine Opmi kerong infection screening, thus obtaining the name of "invisible Omicron".

The Health Safety Agency said it was unclear what effects the changes in the genome of the BA.2 strain would have. Preliminary evidence suggests that the number of cases of BA.2 infection may grow more rapidly compared to BA.1. There is currently insufficient evidence to determine whether BA.2 causes more severe disease than BA.1.

According to the Danish National Serum Institute, preliminary analysis showed no difference between BA.2 and BA.1 strains in terms of hospitalization rates.