A Review on the Contemporary Status of Mutating Coronavirus and Comparative Literature Study of Current COVID-19 Vaccines

The Novel corona virus was first reported in Wuhan province of China in the late 2019. It outspread rapidly which led to a new health crisis throughout the world by the beginning of March 2020 and was considered as a global epidemic. Several deteriorating health symptoms, morbidity and mortality were reported globally by WHO, with more than 34 lakh deaths being reported by 26 May 2021. Presently 16 vaccines are approved under emergency use in different countries and more than 33 vaccines are under phase 3 clinical trials and nearly 130 vaccines are in development phase. By the end of 2020 several new variants in U.K, South Africa, Brazil and India were reported which caused the second wave of COVID-19, for which new trials of vaccine are running to evaluate the efficacy and safety. Several technical problems are associated regarding the production, storing and supplying of these vaccines. For controlling the epidemic, the major challenge is to produce billions of vaccines and to make it available to the underdeveloped and poorer nations. This extensive review provides the details of the different variants of corona viruses reported in the different regions of the world, current vaccines approved under emergency use which are being administered throughout the globe, on-going and listed clinical trials on different vaccines under study for possible use in Covid-19 virus and future challenges associated with Covid-19 scenario.