Literature Review of Omicron: A Grim Reality Amidst COVID-19

Abstract

Coronavirus disease 2019 (COVID-19) first emerged in Wuhan city in December 2019, and became a grave global concern due to its highly infectious nature. The Severe Acute Respiratory Coronavirus-2, with its predecessors (i.e., MERS-CoV and SARS-CoV) belong to the family of Coronaviridae. Reportedly, COVID-19 has infected 344,710,576 people around the globe and killed nearly 5,598,511 persons in the short span of two years. On November 24, 2021, B.1.1.529 strain, later named Omicron, was classified as a Variant of Concern (VOC). SARS-CoV-2 has continuously undergone a series of unprecedented mutations and evolved to exhibit varying characteristics. These mutations have largely occurred in the spike (S) protein (site for antibody binding), which attribute high infectivity and transmissibility characteristics to the Omicron strain. Although many studies have attempted to understand this new challenge in the COVID-19 strains race, there is still a lot to be demystified. Therefore, the purpose of this review was to summarize the structural or virologic characteristics, burden, and epidemiology of the Omicron variant and its potential to evade the immune response.

Performance of Antigen Detection Tests for SARS-CoV-2: A Systematic Review and Meta-Analysis

“…Thus, data collection was completed at a time prior to the emergence of the Omicron variant and thus, the conclusions drawn from this work involve mainly the initial Wuhan strain, Alpha, Beta and Delta (to some extent) variants. A complete treatment of the question regarding the effectiveness of antigen tests against the newly emerged Omicron variant [ 271 ] would require a study of its own, but nevertheless we might be able to highlight some of the available evidence. Initially, there were concerns regarding the effectiveness of the tests [ 272 ], but the first report with the Abbott BinaxNow SARS-CoV-2 Rapid Antigen Assay provided evidence that it can be used efficiently [ 273 ].…”

Is Omicron the end of pandemic or start of a new innings?

“…Although beta strands are more susceptible to mutations than alpha helices, Omicron has a slightly higher random composition [ 55 ]. Omicron adopts a new strategy to enter the host without the help of the transmembrane serine protease 2 (TMPRSS2), so there is a lower or no dependency on the TMPRS22 route for replication, so the involvement of the lungs is limited [ 56 ]. Omicron binds to ACE2 more strongly than Delta, resulting in higher infection rates.…”

“…It is crucial to look into the different aspects of the effectiveness of vaccines, especially when comparing countries that have administered different types of vaccines. The neutralization capacity of Omicron was found to be reduced when the titers of nAbs in sera from vaccinated people were examined [ 56 ]. Existing COVID-19 vaccine protection will not be wiped out, and boosters should help to enhance immunity against Omicron, according to research conducted in South Africa, Germany, and Sweden, as well as by the Pfizer–BioNTech collaboration, despite the fact that they seem to reduce the likelihood of hospitalisation or death.…”

Clinical features of SARS-CoV-2 Omicron BA.2; Lessons from previous observations – Correspondence

“…The Omicron variant has spread rapidly from Africa to Europe, Asia, Australia and America (more than 171 countries) in a short time. Thus, the World Health Organization (WHO) announced Omicron as a Variant of Concern (VOC) on November 26, 2021 [ 1 ]. The Omicron variant outbreak is replaced with the Delta variant due to its more contagious, higher secondary attacks, and higher vaccine breakthrough rate [ 2 , 3 ].…”