The SARS‐CoV‐2 Omicron variant and its multiple sub‐lineages: transmissibility, vaccine development, antiviral drugs, monoclonal antibodies, and strategies for infection control – a review

The Omicron (B.1.1.529), fifth variant of concern (VOC) of SARS-CoV-2, initially identified following a steep increase in COVID-19 cases in Southern Africa in November 2021. It is a highly-mutated variant and is more contagious as compared with the Delta variant, however less deadly. Due to its high transmission rate, it spreads dramatically, and causing huge surges worldwide. It causes "mild infection", with hospitalisations less likely to occur. However, this variant is known to show resistance to neutralizing antibodies (nAbs) generated through vaccination and/or prior infection as well as to monoclonal antibodies (mAbs) used to treat COVID-19 patients. In many countries, booster doses of vaccines have been recommended to increase the protective levels of antibodies in vaccinated individuals. Along with the implementation of appropriate prevention and control strategy measures, current efforts are also focussed on the development of better vaccines and mAbs to counter this variant. This review highlights the global health concerns and challenges posed by the Omicron variant and present an update on its sub-lineages.