A Systematic Review of Genetically Challenging Changes of SARS-CoV-2 Variants; Escaping the Immune System and Vaccine Effectiveness

So far, extensive research has been conducted on the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus and its disease in different regions of the world. The aim of these studies is to present practical findings and suggestions about more familiarity with the characteristics of this virus, including its structural and genetic characteristics, origin of genesis, evolution, genomic changes, biological cycle and pathological function, that can be used to adopt efficient strategies in controlling and treating the pandemic.

In order to perform genomic analysis, the complete sequence of the desired coronaviruses with accession numbers obtained from GenBank or GISAID was stored from databases such as NCBI and BV-BRC, and then the sequences were aligned with Workbench CLC Main software. In the next step, the phylogenetic tree was drawn by Neighbor-Joining method with 1000 repetitions (bootstrap) by MEGA X software and FigTree version 1.4.4 was used to display the tree more clearly. 

All ethical principles in writing this article have been observed according to the instructions of the National Ethics Committee and the COPE regulations.

In the current study, mutations and the effect they may have on transmissibility, pathogenicity and vaccine effectiveness, molecular features, epidemiology and the place of emergence of coronaviruses, focusing on variant of concern (VOC) including alpha (B.1.1.7), beta (B.1.351), gamma (P.1), delta (B.1.617.2) and omicron (B.1.1.529) are presented.

The occurrence of mutations and continuous evolution have led to the rapid and simultaneous emergence of different variants, each of these changes can contribute to the escape of therapeutic methods such as neutralizing antibodies (Nab) and convalescent plasma, as well as reducing the effectiveness of vaccines. Therefore, increasing monitoring for documentation, understanding the spread of different lineages and more detailed study of these mutations in identifying variants and effectively dealing with them is of great importance.