SARS-CoV-2 variants and vulnerability at the global level

J Med Virol. 2022 Jul;94(7):2986-3005. doi: 10.1002/jmv.27717. Epub 2022 Apr 5.


Numerous variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have evolved. Viral variants may evolve with harmful susceptibility to the immunity established with the existing COVID-19 vaccination. These variants are more transmissible, induce relatively extreme illness, have evasive immunological features, decrease neutralization using antibodies from vaccinated persons, and are more susceptible to re-infection. The Centers for Disease Control and Prevention (CDC) has categorized SARS-CoV-2 mutations as variants of interest (VOI), variants of concern (VOC), and variants of high consequence (VOHC). At the moment, four VOC and many variants of interest have been defined and require constant observation. This review article summarizes various variants of SARS-CoV-2 surfaced with special emphasis on VOCs that are spreading across the world, as well as several viral mutational impacts and how these modifications alter the properties of the virus.

Keywords: Delta plus variant; Delta variant; Omicron variant; SARS-CoV-2; mutation; vaccination; viral variant.

Publication types

  • Review

MeSH terms

  • COVID-19 Vaccines
  • COVID-19*
  • Humans
  • SARS-CoV-2* / genetics
  • Spike Glycoprotein, Coronavirus / genetics
  • United States


  • COVID-19 Vaccines
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2

Supplementary concepts

  • SARS-CoV-2 variants