Vaccine development and technology for SARS-CoV-2: Current insight

Abstract

Severe acute respiratory syndrome coronavirus 2 is associated with a severe respiratory disease in China, that rapidly spread across continents. Since the beginning of the pandemic, available data suggested the asymptomatic transmission and patients were treated with specific drugs with efficacy and safety data not always satisfactory. The aim of this review is to describe the vaccines developed by three companies, Pfizer-BioNTech, Moderna, and University of Oxford/AstraZeneca, in terms of both technological and pharmaceutical formulation, safety, efficacy, and immunogenicity. A critical analysis of Phases 1, 2, and 3 clinical trial results available was conducted, comparing the three vaccine candidates, underlining their similarities and differences. All candidates showed consistent efficacy and tolerability; although some differences can be noted, such as their technological formulation, temperature storage, which will be related to logistics and costs. Further studies will be necessary to evaluate long-term effects and to assess the vaccine safety and efficacy in the general population.

Keywords: SARS-CoV-2; lipid nanoparticles; pandemic; pneumonia; vaccine; viral vector.

Figure 1

(A) modRNA including a 5ʹ cap and two untranslated regions (UTR) and the S protein‐coding sequence. (B) 1‐methyl‐5ʹ‐pseudouridine. (C) Pfizer‐BioNTech cationic lipid ALC‐0315. modRNA, nucleoside‐modified RNA

Figure 2

(A) The nanolipid vector (80–100 nm) of Pfizer‐BioNTech and Moderna and the viral vector of Oxford‐AstraZeneca. (B) The nanolipid carrying the mRNA blends the cell membrane entering the cytoplasm through endosomal vesicles. From the endosomes, nanolipids spill out their cargo (mRNA) into the cytoplasm, reaching the ribosomes where mRNA is translated into a spike protein to be processed and presented to MHC‐1, activating CD8+ T cells. Analogously, CD4+ (naive) T‐cells are activated and, by the MHC‐2 activation, the B cells are operative, producing whether memory T cells or plasma cells, which can produce antiviral antibodies. MHC, major histocompatibility complex; mRNA, messenger RNA