Omicron variant of SARS-CoV-2 infection elicits cross-protective immunity in people who received boosters or infected with variant strains

Introduction The B.1.1.529 (Omicron) variant of SARS-CoV-2 is the most antigenically unique SARS-CoV-2 variant of concern to date, which is currently widespread across the world. Omicron variant and its sublineages contain a plethora of mutations than other variants of concern, which increases their transmissibility and virulence. Concerns regarding potential immunological evasion have been reignited by emerging subvariants of the Omicron variant. Determining the effectiveness of Omicron-induced immunity and whether it is cross-protective against other variants is a crucial aspect of the research. Method A systematic search of relevant articles until September 25, 2022, from databases such as PubMed, Scopus, Google Scholar, and ScienceDirect was done independently by two authors. A total of 11 articles discussing about immunological evasion of different Omicron subvariants were included in the study. Results Numerous studies have demonstrated that Omicron variant causes a restricted immune response after infection. Omicron infection boosts preexisting vaccine-induced immunity, but it may not be enough to establish widespread, cross-neutralizing humoral immunity in unvaccinated people. Conclusion Due to co-circulation and the emergence of novel SARS-CoV-2 variants, findings highlight the importance of booster vaccinations for immune protection. More studies should focus on the efficacy of Omicron-induced immunity, its cross-protective properties against other variants, and development of a universal vaccine.