Abstract
Knowledge of a new mutant strain of SARS-coronavirus (CoV-2) is enormously essential to identify a targeted drug and for the development of the vaccine. In this article, we systematically reviewed the different mutation strains (variant of concern [VOC] and variant of interest [VOI]) which were found in different countries such as the UK, Singapore, China, Germany, Vietnam, Western Africa, Dublin, Ireland, Brazil, Iran, Italy, France, America, and Philippines. We searched four literature databases (PubMed, EMBASE, NATURE, and Willey online library) with suitable keywords and the time filter was November 2019 to June 16, 2021. To understand the worldwide spread of variants of SARS-CoV-2, we included a total of 27 articles of case reports, clinical and observational studies in the systematic review. However, these variants mostly spread because of their ability to increase transmission, virulence, and escape immunity. So, in this paper is we found mutated strains of SARS-CoV-2 like VOCs that are found in different regions across the globe are ALPHA strain in the U.K, BETA strain in South Africa, GAMMA strain in Brazil, Gamma and Beta strains in European Countries, and some VOIs like Theta variant in the Philippines.