A review on covid-19: From molecular variability, drug development to status of vaccine clinical trials

Abstract

A pandemic has erupted in all parts of the globe, originating from Wuhan province in China in December 2019. The virus was evaluated from the Coronaviridae family and Co ronaviridae subfamily, which showed homology with another virus spread across the globe originating from China in November 2002. It also showed pneumonia-like symptoms and was known as Severe Acute Respiratory Syndrome (SARS). SARS CoV-2 is the new 2019 virus believed to show animal to human transmission and vice-versa. Many intermediate hosts should be included to be suitable for human receptors. Finally, the virus could have evolved due to RNA recombination in the high frequency of the significant result of the plastic genome underpinning all the evolutionary forces in CoVs. This resulted in the adaptation of various hosts by this virus due to different genotypes. In the genome, there are 6-10 ORFs. Starting 2/3rd of the genome codes for replicase protein and the part has a fixed order of structural protein genes as (HE)-S-E-M-N. In Human beings, the virus first infects respiratory systems and alveolar cells in the lungs. The cellular receptor for the SARS virus is angiotensinconverting enzyme2 (ACE2). The existing reviews mostly focus on specific areas of COVID19. This review gives a comprehensive phylogeny analysis and genetic makeup of the virus, making it a target site for scientists looking for a fair comparison. It provides brief information on mutation undergoing by the virus, various drugs being used and stages of drug development, vaccine development, and its administration across the world, side effects of the vaccine, which are currently trending topics. We concentrated mainly on diversifying our review and making it unique by covering all the required information. This review would be more beneficial to the researcher and a general reader to understand the COVID 19.