SARS-CoV-2 new variants: Characteristic features and impact on the efficacy of different vaccines

Abstract

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its new variants reported in different countries have posed a serious threat to human health and social fabrics worldwide. In addition, these new variants hindered the efforts of vaccines and other therapeutic developments. In this review article, we explained the emergence of new variants of SARS-CoV-2, their transmission risk, mortality rate, and, more importantly, the impact of each new variant on the efficacy of the developed vaccines reported in different literature and findings. The literature reported that with the emergence of new variants, the efficacy of different vaccines is declined, hospitalization and the risk of reinfection is increased. The reports concluded that the emergence of a variant that entirely evades the immune response triggered by the vaccine is improbable. The emergence of new variants and reports of re-infections are creating a more distressing situation and therefore demands further investigation to formulate an effective therapeutic strategy.

Keywords: Infectivity; New Variants; Pathogenesis; SARS-CoV-2; Therapeutics; Vaccine.

Fig. 1

Graphical representation of SARS-CoV-2 structure. Interspersed genomic regions are also shown in the right panel (created with biorender.com).

Fig. 2

The attachment of spike protein to the ACE2 of human cells for infection. The S1, S2 and cleavage site of S protein is depicted to clearly show the early stage of infection (created with biorender.com).

Fig. 3

Graphical illustration of the genomic regions of SARS-CoV-2. The two open reading frames (ORF1a and ORF1B), their nucleotides dimension, and the protein encoded by a specific region is given in detail (created with biorender.com).

Fig. 4

SARS-CoV-2 genome replication pathway and life cycle in the host cell (created with www.biorender.com).