Therapeutic approaches and vaccination in fighting COVID-19 infections: A review

Abstract

Coronavirus disease 2019 (COVID-19) is a remarkably contagious and pathogenic viral infection arising from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first appeared in Wuhan, China. For the time being, COVID-19 is not treated with a specific therapy. The Food and Drug Administration (FDA) has approved Remdesivir as the first drug to treat COVID-19. However, many other therapeutic approaches are being investigated as possible treatments for COVID-19. As part of this review, we discussed the development of various drugs, their mechanism of action, and how they might be applied to different cases of COVID-19 patients. Furthermore, this review highlights an update in the emergence of new prophylactic or therapeutic vaccines against COVID-19. In addition to FDA or The World Health Organization (WHO) approved vaccines, we intended to incorporate the latest published data from phase III trials about different COVID-19 vaccines and provide clinical data released on the networks or peer-review journals.

Keywords: ACE2, Angiotensin-converting enzyme 2; ARDS, Acute respiratory distress syndrome; Antiviral agents; Arb, Arbidol; COVID-19; COVID-19, Coronavirus disease 2019; ER, Endoplasmic reticulum; ERGIC, Endoplasmic reticulum Golgi intermediate compartment; FDA, Food and Drug Administration; HIV, Human immunodeficiency virus; MERS-CoV, The Middle East respiratory syndrome 20 coronavirus; ORFs, Open reading frames; Pandemics; Pneumonia; RBD, Receptor binding domain; RTC, Replicase transcriptase complex; RdRp, RNA-dependent RNA polymerase; SARS-CoV-2; SARS-CoV-2, Severe acute respiratory syndrome of coronavirus 2; VLPs, Virus-like particles; Vaccines; WHO, World Health Organization; WMT, Washed microbiota transplantation; gRNA, Genomic RNA; mAbs, Monoclonal antibodies; sgRNA, Subgenomic RNA.

Fig. 1

SARS-CoV-2 life-cycle and the inhibitory mechanism of some very important antiviral drugs. After attachment to the receptor, the virus will next penetrate the cytosol of the host cell. The next process in the coronavirus lifespan involves the translation of the replicase gene from genomic RNA (gRNA) of the virion, which produces two co-terminal polyproteins, pp1a and pp1ab. Then, almost all the NSPs combine into the Replicase-Transcriptase Complex (RTC) to make an area appropriate for the synthesis of RNA and are conclusively responsible for the subgenomic RNA (sgRNA) replication and transcription. sgRNAs act as mRNAs for the structural and accessory genes existing downstream of the replicase polyprotein. Both gRNAs and sgRNAs are generated by negative-strand intermediate RNAs. The viral structural proteins, S, E, and M, are translated then introduced into the endoplasmic reticulum (ER) after replication and synthesis of the (+) sgRNA. Such proteins pass into the endoplasmic reticulum – Golgi intermediate compartment (ERGIC) along the secretory process. Then, the genome of the virus enclosed by N protein bud within ERGIS membranes, which consists of other viral structural proteins creating mature virions. The particles are transported through vesicles to the cell surface after assembly and released by exocytosis.