SARS-CoV-2 (Covid-19) vaccines structure, mechanisms and effectiveness: A review

Abstract

The world has been suffering from COVID-19 disease for more than a year, and it still has a high mortality rate. In addition to the need to minimize transmission of the virus through non-pharmacological measures such as the use of masks and social distance, many efforts are being made to develop a variety of vaccines to prevent the disease worldwide. So far, several vaccines have reached the final stages of safety and efficacy in various phases of clinical trials, and some, such as Moderna/NIAID and BioNTech/Pfizer, have reported very high safety and protection. The important point is that comparing different vaccines is not easy because there is no set standard for measuring neutralization. In this study, we have reviewed the common platforms of COVID-19 vaccines and tried to present the latest reports on the effectiveness of these vaccines.

Prevalence of COVID-19 vaccines (Sputnik V, AZD-1222, and Covaxin) side effects among healthcare workers in Birjand city, Iran

“…Both vaccines contain adenoviruses that infect cells and provide the genetic code of the spike protein to infected cells, leading to the expression of spike protein by infected cells. Then, infected cells do present spike on the surface to T-cells [14] . These vaccines (Sputnik V and AZD-1222) increase both cellular and humoral immunity and triggers strong immune responses [14] .…”

“…Then, infected cells do present spike on the surface to T-cells [14] . These vaccines (Sputnik V and AZD-1222) increase both cellular and humoral immunity and triggers strong immune responses [14] . Clinical trial results demonstrated that Sputnik V and AZD-1222 have considerable safety and immunogenicity and induces antibody production against spike protein [2] , [15] .…”

“…Nevertheless, this approach is not suitable for all viruses, and may lead to serious safety concerns, if the molecular and structural understanding of the antigen is incomplete [17] . Firstly, virus particles are traditionally obtained from virus-infected cells, then using a variety of physical and chemical procedures, including the use of β-propiolactone and UV, coronaviruses are deactivated [14] , [16] . The polio vaccine, as a classic example of a whole killed virus vaccine, has been in the global vaccination program for many years [18] .…”

Spectrum of Neuroimaging Findings in Post-COVID-19 Vaccination: A Case Series and Review of Literature

“…Among the 3 vaccines approved by the Emergency Use Authorization (EUA), Pfizer-BioNTech BNT162b and Moderna mRNA-1273 are mRNA vaccines that code for S-protein antigens. Ultimately, these vaccines are composed of SARS-CoV-2 glycoproteins and lipid nanoparticles adjuvants, which induce B-cell and T-cell response [9]. The Janssen COVID-19 vaccine is a recombinant, adenovirus vector-based vaccine that encodes the SARS-CoV-2 spike protein.…”

Effect of heterologous vaccination regimen with Ad5-nCoV CanSinoBio and BNT162b2 Pfizer in SARS-CoV-2 IgG antibodies titers

“…Nowadays, there are 22 approved vaccines with different mechanisms of action to develop spike-specific IgG antibodies with neutralizing capacity against SARS-CoV-2 [3]. The different designs of SARS-CoV-2 vaccines are: Messenger RNA vaccines (BNT162b2 Pfizer/BioNTech, mRNA-1273 Moderna), adenoviral-vectored vaccines (AZD1222 Oxford/AstraZeneca, Gam-COVID-VAC/Sputnik V, Janssen, Ad5-nCoV CanSinoBio), protein subunit vaccines (NVX-CoV2373 Novavax, Medicago CoVLP), whole-cell inactivated virus vaccines (CoronaVac Sinovac, BBIBP-CorV Sinopharm), and DNA vaccines (INO-4800 and ZyCoV-D) [4,5].…”