The Coronavirus disease (COVID-19), caused by sever acute respiratory syndrome coronavirus -2 (SARS-CoV-2) and its various emerging variants, is posing very high health threats with its continued pandemic waves with 5.5 millions deaths out of 272 million confirmed cases reported worldwide as of December 17, 2021, and recently again a rapid surge of cases is being seen at global level. 1-41-4 After the Alpha, Beta, Gamma and Delta SARS-CoV-2 variant of concerns (VOCs), the most recent B.1.1.529 variant (named as Omicron) classified as VOC by WHO on 26 November 2021, is creating alarming situations worldwide. The first case of Omicron was documented from Botswana, South Africa in early November month, and within a very short time this variant has now spread rapidly to 108 countries with nearly 1.5 lakh reported cases and 26 deaths as on December 25, 2021. 5-95-9

The emergence of Omicron (B.1.1.529) variant was documented with a steep increase of COVID-19 cases in South Africa, and was classified as variant of concern on 26^th November, 2021 by the WHO. This highly muted variant is found to be more contagious but less deadly than the Delta variant, and in a short time of few weeks it has spread to nearly 150 countries and territories while causing a very huge surge in COVID-19 cases across the globe. The main clinical manifestations are those of a "mild infection", therefore hospitalisations are less likely but its higher transmission rate is a major concern. Omicron has shown immune escape from neutralizing antibodies generated through previous infection or vaccination as well as could evade the protection provided by monoclonal antibodies (mAbs) being used in clinics for treating COVID-19 patients. Booster dose of vaccines is recommended to elevate the protective levels of antibodies in vaccinated individuals. High efforts are being made to develop highly efficacious vaccines, find out additional mAbs and implement appropriate prevention and control strategies to counter Omicron. This article highlights the global health concerns, challenges and recent updates on this newly emerged variant.