‘Invisible Omicron’ variant spreads rapidly and accounts for one-fifth of new infections globally

The BA.2 sub-variant of Omicron, also known as the “stealth variant,” is spreading rapidly and accounts for about one-fifth of new COVID-19 infections globally, according to the World Health Organization.

On February 17, the World Health Organization (WHO) released a new report on the Omicron BA.2 subvariant, showing that the virus accounts for 21.5% of all new Omicron cases. .analyze. .The first week of February worldwide. Meanwhile, Omicron accounts for the majority of global infections, with 98.3% of sequencing samples submitted to the GISAID Data Sharing Center in the past 30 days.

As of February 15, BA.2 (also known as “Invisible Omicron”) accounted for the majority of new infections in 10 countries including Denmark, India, China, Bangladesh, Brunei, Guam, Montenegro, Nepal, Pakistan and the Philippines . However, the World Health Organization report states that there is considerable global variability, “with the highest prevalence of BA.2 (44.7%) reported in Omicron gene sequences in Southeast Asia, while in Asia the lowest prevalence was reported in the United States ( 1%) .”

That’s good news for the U.S., where most states are lifting restrictions after a wave of Omicrons this past winter. Here, the popularity of the subvariable BA.2 rose from 1.2% for the week ended Jan 29, 2022 to 3.6% for the week ended Feb 5, 2022, but remains a small fraction.

In contrast, the prevalence of the new strain of Omicron in South Africa increased significantly from 27% in 4/2 to 86% in 11/2. In the UK, the rate of “invisible Omicron” infections increased six-fold between January 17 and 31, from 2.2% to 12%. From the last week of 2021 to mid-January 2022, the number of BA.2 cases in Denmark doubled, from 20% to 45%. From the third week of January 2021, BA.2 became the dominant variant in Denmark, with 66% of the samples sequenced.

A late January report by the Statens Serum Institute, which operates with the support of the Dutch Ministry of Health, suggested that BA.2 could account for “nearly 100% of all new COVID-19 cases” by mid-month. 2 years 2022″. The report also states that the “stealth Omicron” is nearly 30% faster than the original Omicron (B.A1). The report says the rapid rise in BA.2 may therefore result in a steeper epidemic curve and higher peak, and may Postponing the decline in infection rates until May 2,” the report said. .

The World Health Organization (WHO), one of the first major agencies to raise concerns about the new virus, developed its current BA.2 assessment, which shows discrepancies. Its true relevance to other variants lies mainly in its spread.

The reason for the use of Omicrons between countries is unclear. “Due to restrictive and confidential regulations, differences in infectivity between countries may be related to differences in vaccination coverage and exposure patterns,” the WHO report said. “Population et al.”

Denmark has recently lifted almost all COVID-19 restrictions, but according to Johns Hopkins University, the vaccination rate of its citizens is very high, over 80%. Meanwhile, only 65 percent of U.S. citizens have been vaccinated. However, the US has not seen a sub-micron surge in Denmark despite the widespread lifting of restrictions on wearing masks. Meanwhile, in South Africa, where Omicron was first identified and dominated by BA.2, only 29% of the population has been fully immunized and everyone is still required to wear masks in public. . . at home.

The “invisible Omicron” subvariant has sparked another pandemic as it appears to be spreading faster than any other version of COVID-19 to date. The good news is that current vaccines still offer protection against this variant.

The original Omicron variant, known to scientists as BA.1 or B.1.1.529, was only recently the most infectious version of SARS-CoV-2 known. It has led to the highest and steepest peaks in new infections in many countries. But now the “descendant” of BA.1, known as BA.2, is spreading faster and may soon become the dominant version of the virus.

According to the World Health Organization, the sub-variant has appeared in at least 69 countries. BA.2 is not sufficiently different to be classified as a completely new variant with its own Greek name, but it has about 20 mutations that make it different from BA.1. Complicatingly, it does not contain mutations that distinguish Omicron from other variants in PCR analysis, making it more difficult to distinguish BA.2 from Delta. That’s why some researchers describe BA.2 as an “invisible Omicron.”

However, it is unclear whether BA.2 is sufficient to cause reinfection in people already infected with BA.1. In other words, if you’re infected with the main Omicron variant, scientists don’t know if

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