A tabulated summary of the evidence on humoral and cellular responses to the SARS-CoV-2 Omicron VOC, as well as vaccine efficacy against this variant.

INTRODUCTION: SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the virus responsible for COVID-19. It is one of the most mutating virus in the world. These mutations are responsible for the appearance of new variants, the most recent of which is Omicron (line B.1.1.529). This new variant was first identified in South Africa in November 2021. The main fear with this variant is that of an immune escape and ineffectiveness of vaccines currently available. OBJECTIVE: We studied the response of our immune system and the effectiveness of current vaccines against SARS-CoV-2 Omicron VOC. METHODS: We carried out a narrative review from 32 scientific articles from databases: MEDLINE (PubMed), Embase, BioRxiv and MedRxiv. RESULTS: Faced with SARS-CoV-2 Omicron VOC: The humoral immune response decreased, while the cellular immune response was preserved. The booster vaccine provided protection against symptomatic or non-symptomatic infections, transmission, and serious forms. CONCLUSION: In the end, according to these data, the 3rd dose appears to be the solution to be able to defeat SARS-CoV-2 Omicron VOC. But the health authorities must not forget to insist on the primary vaccination of individuals not yet vaccinated, as well as on an "equal" distribution of vaccines against COVID-19 throughout the world.