Implication of SARS-CoV-2 Immune Escape Spike Variants on Secondary and Vaccine Breakthrough Infections

Abstract

COVID-19 pandemic remains an on-going global health and economic threat that has amassed millions of deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of this disease and is constantly under evolutionary pressures that drive the modification of its genome which may represent a threat to the efficacy of current COVID-19 vaccines available. This article highlights the pressures that facilitate the rise of new SARS-CoV-2 variants and the key mutations of the viral spike protein - L452R, E484K, N501Y and D614G- that promote immune escape mechanism and warrant a cautionary point for clinical and public health responses in terms of re-infection, vaccine breakthrough infection and therapeutic values.

Keywords: COVID-19; SARS-CoV-2; breakthrough infection; immune evasion; secondary infection; spike protein; vaccine; variants.

Figure 1

An illustration of SARS-CoV-2 spike protein mutations identified in its subunit 1 that have been (A) shown to promote resistance to neutralizing monoclonal antibodies (⎔) and serum antibodies (from convalescent (●) and/or vaccinated (⦰) individuals), and increase the protein affinity to ACE2 receptor (◯) and viral infectivity (■) and (B) reported in breakthrough and/or secondary infections.