Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 51 7 2022 07 09 1494 1501 Dariush Farhud 1. School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2. Departments of Basic Sciences/Ethics, Iranian Academy of Medical Sciences, Tehran, Iran 3. Farhud Genetics Clinic, Tehran, Iran Nooshin Mojahed 1. Farhud Genetics Clinic, Tehran, Iran 2. Department of Biology, Faculty of Science, North Branch, Islamic Azad University, Tehran, Iran 2022 05 10 2022 07 09 SARS-COV-2 (COVID-19) the virus that caused an epidemic of sever acute respiratory syndrome is what the world has been dealing with since Dec 2019. As the pandemic continues different variants that emerge during mutations have become the latest concern, with notable examples detected in South Africa, Brazil, and UK. Variants are complicated and each one is a collection of several mutations, all of which have the potential to change the virus in unexpected ways. Studying variants is imperative as they can lead the epidemic to the increase of population immunity. In the present study, we reviewed key mutations and concerning variants according to the WHO tracking Sars-Cov-2 program. Databases were searched through Feb to Mar 2022. Overall, 477 studies were extracted from databases, among them 165 studies included mutations, 239 included COVID-19 variants and 43 included both mutations and variants. At the final step of data screening 24 studies associated to mutations, 31 studies with the highlighted information on COVID-19 variants and 31 studies related to both mutations and variants were extracted for this review article. In conclusion, analyses of the genomic sequence of SARS-CoV-2 indicate that structural proteins are key molecules in the assembly of virus while NSPs can have different biochemical properties and possibly cellular functions. https://ijph.tums.ac.ir/index.php/ijph/article/view/28700 https://ijph.tums.ac.ir/index.php/ijph/article/download/28700/7649