key: cord-1048215-5iusp44i authors: Rahimi, Farid; Talebi Bezmin Abadi, Amin title: Is Omicron the last SARS-CoV-2 Variant of Concern? date: 2022-01-19 journal: Arch Med Res DOI: 10.1016/j.arcmed.2022.01.001 sha: 7b17e33363eb2fc86ed08eeea0cce55cef5ddf55 doc_id: 1048215 cord_uid: 5iusp44i Millions have died due to the COVID-19 pandemic. The irrepressible propensity of the pandemic, which was highlighted by the outbreak of the Delta variant, should not be underestimated. The Omicron SARS-CoV-2 variant is thought to have originated from Africa. Sequences of the omicron variant show that it carries the highest number of point mutations detected in a betacoronavirus. High hospitalization numbers due to the Omicron variant has retriggered precautionary restrictions and border closures even in countries which have attained herd immunity by mass vaccinations. Surveillance systems for accurate screening of the Omicron variant are needed to guide implementation of hygiene principles and restrictions. Development of vaccines against the variants is important as the pandemic evolves. Whether Omicron is the last variant depends on the success of the local and global public-health strategies against SARS-CoV-2. https://covariants.org/shared-mutations). For example, P681H is shared among Omicron and two VOCs (Alpha and Delta). D614G, the most common mutation, is present also in the Omicron genome. These Omicron mutations has raised concern among the scientists and decision-makers, calling for adaptation of strategies in the fight against SARS-CoV-2. Initial assessments suggest that the Omicron variant could more avidly bind to the human host cells than the former dominant variants, including Alpha and Delta (12, 13) . The Omicron mutations have implications for its functional biology, potentially adversely affecting the vaccine efficacy worldwide. If the efficacies of the approved vaccines are affected, the Omicron variant may not be the last VOC we encounter during this pandemic. Whether hospitalizations due to the Omicron variant will increase globally is unpredictable now. However, considering restoring some public-health countermeasures is prudent to avoid further casualties, even in countries with optimal rates of full vaccination. Detection and spread of the Omicron VOC in many more countries is expected; however, avoiding case surges with Delta and Omicron variants is ideal to assist the healthcare facilities in many of countries. Nevertheless, some experts predict that the disease due to the Omicron VOC is less severe than with other variants. Emergence of the Delta variant was not reported opportunely, but Omicron was quickly reported by the relevant authorities. Subsequently, border closures and counter-responses were implemented to curb the spread of the variant (14) . While mass production of the vaccines in 2021 is an important health measure against the pandemic, persistent emergence of the new SARS-CoV-2 variants will likely require additional measures, including longer quarantine periods, physical distancing especially indoors, travel bans, mask wearing, and targeted vaccination campaigns. Reducing the chance of emergence of new viral variants may be difficult; however, preventing uncontrolled spread of the virus may facilitate this ideal aim. Sequencing facilities to accurately screen and track the spread of the variants is necessary for guiding the public-health measures. Developing vaccines with broader efficacy is critical, considering the emergence of the variants such as Omicron. Characteristics of SARS-CoV-2 and COVID-19 Emergence of a new SARS-CoV-2 variant in the UK Emergence of a novel SARS-CoV-2 variant in Southern California Spread of a SARS-CoV-2 variant through Europe in the summer of 2020 Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization Molecular basis of immune evasion by the delta and kappa SARS-CoV-2 variants First reported cases of SARS-CoV-2 sublineage B. 1.617. 2 in Brazil: an outbreak in a ship and alert for spread Introduction of the South African SARS-CoV-2 variant 501Y.V2 into the UK Variant analysis of SARS-CoV-2 genomes Omicron variant drives rise in Covid-19 hospitalizations in South Africa hot spot: The Wall Street Journal A vaccine targeting the RBD of the S protein of SARS-CoV-2 induces protective immunity Confronting the Delta variant of SARS-CoV-2, summer 2021 Severity of SARS-CoV-2 Alpha variant World closing its doors to African countries due to omicron: Anadolu Agency None. None.