|
 
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| REVIEW ARTICLE |
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| Year : 2022 | Volume
: 7
| Issue : 1 | Page : 7-9 |
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The latest variant of concern by the World Health Organization: An Overview
Tanushree Kapil1, Rahul Srivastava2
1 Intern, Rama Dental College, Hospital and Research Centre, Kanpur, Uttar Pradesh, India
2 Reader, Department of Oral Medicine and Radiology, Rama Dental College, Hospital and Research Centre, Kanpur, Uttar Pradesh, India
| Date of Submission | 02-Jan-2022 |
| Date of Acceptance | 31-Jan-2022 |
| Date of Web Publication | 28-Feb-2022 |
Correspondence Address:
Dr. Tanushree Kapil
Rama Dental College, Hospital and Research Centre, A-1/8, Lakhanpur, Kanpur - 208 024, Uttar Pradesh
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ijmo.ijmo_1_22
The latest coronavirus strain – Omicron variant of severe acute respiratory syndrome coronavirus-2 – has been identified as the “variant of concern” by the World Health Organization and has emerged as a global concern. The mutations of its genome encode a section in its spike protein which is utilized to infect host cells. Omicron is more transmissible than its Delta predecessor and has rapidly become the dominant strain in the U. S. This article reviews the recent information and literature available for the Omicron variant.
Keywords: Coronavirus, coronavirus disease, Omicron, variant of concern
How to cite this article:
Kapil T, Srivastava R. The latest variant of concern by the World Health Organization: An Overview. Int J Med Oral Res 2022;7:7-9 |
How to cite this URL:
Kapil T, Srivastava R. The latest variant of concern by the World Health Organization: An Overview. Int J Med Oral Res [serial online] 2022 [cited 2022 Dec 4];7:7-9. Available from: http://www.ijmorweb.com/text.asp?2022/7/1/7/338802 |
| Introduction | |  |
Nidovirales order of the Coronaviridae family is where the zoonotic coronavirus belongs and leads to respiratory illnesses. The virus, discovered in 1937, appeared like a crown under the microscope; hence, the term coronavirus was coined in 1965. Since then, various coronaviruses have been reported, for example, the alphacoronaviruses such as HCoV-229E and HCoV-NL63; the betacoronaviruses such as HCoV-OC43 and HCoV-HKU1; severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome, and SARS-CoV-2 described as coronavirus disease-2019 (COVID-19).[1],[2] Coronaviruses are highly infective to humans and other mammals and aves and affect the respiratory, gastrointestinal, and neurological systems. The most prevalent coronaviruses are 229E, OC43, NL63, and HKU1, which induce common cold-like symptoms. SARS-CoV-2 is the third prevalent virus which has spread like a pandemic in the last two decades, causing serious sickness.[3] Technical Advisory Group on SARS-CoV-2 Virus Evolution determines whether certain mutations or combinations of mutations alter the virus's behavior. On November 24, 2021, the B.1.1.529 variant was initially reported by South Africa which was marked by three different peaks in reported cases. Infections rose sharply in recent weeks, corresponding to the discovery of the B.1.1.529 strain. The first known confirmed B.1.1.529 infection was from a specimen collected on November 9, 2021. On November 26, 2021, the TAG-VE met to analyze the SARS-CoV-2 variant B.1.1.529.[4]
| Emergence of Omicron and its Transmissibility | | |
Genetic monitoring to track variations of SARS-CoV-2 is employed by various disease prevention groups and guides public health management throughout the epidemic.
November 24, 2021: the World Health Organization (WHO) has received notification of a new SARS-CoV-2 mutation, B.1.1.529 which was discovered in specimens taken in Botswana on November 11, 2021, and in South Africa on November 14, 2021.
November 26, 2021: The B.1.1.529 was termed as Omicron by WHO and classified it as a variant of concern (VOC).
November 30, 2021: Omicron was designated as a VOC at USA.
December 1, 2021: U. S. reported its first ever case of Omicron.[5]
The spike protein of the Omicron has 32 mutations and there are 50 mutations overall. The spike protein has protruding knobs on the outside of the SARS-CoV-2 virus which is used to adhere and gain entry into cells. Its predecessor variant Delta had only nine mutations. Around 50 mutations of Omicron make it more transmissible and/or breaching the immunity which is concerning.[6]
Omicron's capacity to proliferate quickly appears to be one of the secrets to its success. Omicron resides in bronchus, multiplies in mere 24 h, and infects 70 times quicker there as per the researchers.[7]
| The New Coronavirus Disease Variant, Omicron, how much do we know? | | |
Several studies have discovered that Omicron variant has over 30 alterations/mutations in its spike protein. Spike protein is the mainstay on which the current COVID-19 vaccines are based upon, as it targets and enters the host cells. Since the pandemic started Beta and Delta had couple of mutations in their spike proteins, whereas Omicron has 10 mutations in its spike protein linked to the angiotensin-converting enzyme 2 receptor.
These mutations fuel this variant's rate of transmissibility. The E484A mutation located at the site can evade action by Class 2 human antibodies. Researchers believe this variant due its mutations may neutralize the immune response generated from prior infections and or vaccines.[8]
| Mutational Hotspots of Omicron | | |
Of the 30 amino acid substitutions in the spike glycoprotein, there are three small deletions and one tiny insertion. About 15 of the mutations reside in the receptor-binding domain (RBD). This variant is from Pango lineage B.1.1.529, the Nextstrain clade 21K has 30 amino acid modifications, three modest deletions, and one short insertion in the spike protein.
These mutations are identified as Ala67Val, Δ69–70, Thr95Ile, Gly142Asp, Δ143–145, Δ211, Leu212Ile, ins214EPE, Gly339Asp, Ser371Leu, Ser373Pro, Ser375Phe, Lys417Asn, Asn440Lys, Gly446Ser, Ser477Asn, Thr478Lys, Glu484Ala, Gln493Arg, Gly496Ser, Gln498Arg, Asn501Tyr, Tyr505His, Thr547Lys, Asp614Gly, His655Tyr, Asn679Lys, Pro681His, Asn764Lys, Asp796Tyr, Asn856Lys, Gln954His, Asn969Lys, and Leu981Phe where 15 (residues 319–541) of these modifications resides in the RBD.
Apart from these mutations, there are quite a few substitutions and deletions in the genomic areas. These mutations are visualized on nonstructural protein (NSP) 3 as Lys38Arg, SΔ1265, Leu1266Ile, and Ala1892Thr; NSP4 as Thr492Ile; NSP5 as Phe132His; NSP6 as Δ105–107 and Ile189Val; NSP12 as Pro323Leu; NSP14-Ile42Val; envelope (E) as Thr9Ile; membrane (M) as Asp3Gly, Gln19Glu, and Ala63Thr; nucleocapsid (N) as Pro13Leu, Δ31–33, Arg203Lys, and Gly204Arg. In comparison to other predominant VOCs, Omicron has been highly mutated.[9],[10],[11],[12]
| Symptoms of Omicron | | |
The symptoms associated with this variant are not different from other variants, but there is a possibility of increased death rate.
Cold-like upper respiratory symptoms grew more common as Delta became the main form, whereas loss of taste and smell became less common than in other variants.
The duration to develop symptoms has been reduced for Omicron from 7 days to as less as 2–3 days.
Muscle aches, fatigue, a scratchy throat, and night diaphoresis/sweat are common Omicron symptoms.
Coetzee describes Omicron symptoms as less aggressive with no loss of smell or taste and no significant decline in oxygen levels. A runny nose, headache, fatigue (moderate or severe), sneezing, and sore throat were common symptoms. People who have received two doses of the vaccine typically present with less severe symptoms.[13],[14]
| Diagnosis | | |
A diagnostic system has been developed by Korean scientists to detect Omicron variations. The system has been developed, but the commercial availability would take some time.
COVID-19 variations are currently detected by using three methods: whole-genome analysis, target DNA (mutations such as spike protein) analysis, and polymerase chain reaction (PCR) test. Omicron has evaded the current PCR test administered as gold standard for Delta Variant.
The newly developed technology has incorporated molecular diagnosis and not the sequencing method that reads DNA or RNA sequences. The existing technology screens only specific areas of the virus, but the molecular diagnostic technology was designed to cause nucleic acid-binding reactions only when the COVID-19 RNA exists, enabling rapid detection. According to Lee, Omicron has a weak signal for S genes and strong one for N genes. In the case of “Stealth Omicron,” both N and S genes confirmed positive, making it difficult to distinguish from other variants. The molecular diagnostic technology detects the Omicron variant efficiently.[15]
| Tools for Combating Omicron | | |
The instructions listed below may prevent the aggressive transmissibility of the Omicron variation:
- Increased COVID-19 testing
- Maintain social distancing
- Wearing a mask
- Travel bans (if required)
- Avoid populated areas
- Cough or sneeze hygiene
- Follow handwashing protocol
- Increased COVID-19 vaccinations
- Suitable treatment facilities for older patients and those with comorbidities.[13]
| Conclusion | | |
Travel bans have again been imposed considering this could be the third wave of the pandemic. In an already weary, psychosocial, and economically affected world, this new variant Omicron has emerged. More study is needed to completely comprehend the severity, transmission capacity, diagnostic test efficacy, efficacy of currently available vaccines, and appropriate treatments.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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