1. Introduction
The COVID-19 pandemic, the biggest public health crisis in a century has caused an estimated 476 million cases and 6.1 million deaths till date globally. [1]
During the pandemic, multiple variants of SARS-CoV-2 have emerged that have been found to vary in transmissibility and severity. Omicron (B.1.1.529) variant has emerged after Alpha, Beta, Gamma and Delta SARS-CoV-2 variants, during November 2021 as a highly mutated virus variant, classified as variant of concern (VOC) by WHO on 26 November 2021, that has now attained the position of a dominant strain in several countries owing to its very high transmissibility [2]. With the emergence of the Omicron (B.1.1.529) variant of SARS-CoV-2, there is remarkable decrease in the disease severity relative to previous variants such as Delta (B.1.617.2). The lower disease severity seen in populations during the Omicron wave of the SARS-CoV-2 pandemic infection [3] can be attributed to changes in the virus that limit its ability to spread in the lungs and, probably most importantly, to increased immunity in the population from previous SARS-CoV-2 infection and vaccination [4]. In the last 6 months cases of COVID 19 are declining [1]. It seems that, the disease is going towards endemicity.
The patients infected with Omicron variant have shorter hospital stay, lesser number of patients receiving intensive care, and fewer deaths than delta variant. Though presenting as low severity disease, its higher transmissibility might present a threat for co-morbid patients [2].
The present study deals with comparison of morbidity and mortality with SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants.