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Global Translational Medicine

REVIEW ARTICLE
Comparative analysis of immune responses in

humans infected with Alpha, Delta, and Omicron
strains of SARS-CoV-2

1,2
Mihieka Bose and Chayan Munshi *
1
1 Ethophilia Research Foundation, Santiniketan, India
2 Department of Zoology, Visva Bharati University, Santiniketan, India

Abstract
The COVID-19 pandemic outbreak has profoundly challenged global public health
over the last couple of years. Throughout this period, numerous mutant strains
of SARS-CoV-2 have emerged, presenting diverse pathophysiology and immune
response challenges for infected individuals. Among these, variant of concern strains,
including Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529), has garnered
the most significant attention for their role in causing epidemiological dynamics,
ultimately leading to elevated infectivity and significant mortality rates. This
review aims to provide a comparative analysis of the immune-pathophysiological
mechanisms associated with these aforementioned strains of SARS-CoV-2.

Keywords: SARS-CoV-2; Immune response; Pandemic

*Corresponding author:
Chayan Munshi 1. Introduction
(chayanbio@gmail.com)
Over the past 3 years, the global SARS-CoV-2 epidemic has imposed significant strain
Citation: Bose M, Munshi C.
Comparative analysis of immune on human immunity, resulting in numerous viral outbreaks that have claimed many
responses in humans infected with lives and negatively impacted public health. Across several virologically distinct waves,
Alpha, Delta, and Omicron strains
of SARS-CoV-2. Global Transl Med. SARS-CoV-2 has employed mutation mechanisms that changed its interaction with the
2024;3(1):2228. host body. Correspondingly, the human immune response has also been modified as
https://doi.org/10.36922/gtm.2228 the viral strains evolved. The World Health Organization has identified several variants
Received: November 10, 2023 of concern (VOC) during the COVID-19 pandemic, including Alpha, Beta, Gamma,
Accepted: December 25, 2023 Delta, and Omicron. Although these strains have diversified into additional subtypes
1
Published Online: March 19, 2023
over time, our focus remains primarily on the Alpha, Delta, and Omicron variants due to
Copyright: © 2024 Author(s). their significant influence. Throughout the pandemic, these three strains have exhibited
This is an Open Access article
distributed under the terms of the significantly higher degrees of pathogenicity and transmissibility in comparison with
Creative Commons Attribution other circulating strains, affecting a vast population around the globe. The characteristic
License, permitting distribution, route of invasion or biomarking remains consistent across all these strains. As a member
and reproduction in any medium,
provided the original work is of the coronavirus family, SARS-CoV-2 spreads through the air, gaining entry into the
properly cited. human respirational tract. Subsequently, it gains access to various cell types by utilizing
Publisher’s Note: AccScience its viral spike protein, leading to severe respiratory distress and other clinical symptoms.
Publishing remains neutral with In comparison with its predecessors, the Middle East respiratory syndrome, and severe
regard to jurisdictional claims in
published maps and institutional acute respiratory syndrome-1 (SARS-CoV-1), this virus has a far greater impact on
affiliations. public health due to its high disease spread and pathogenicity, which is tightly controlled

Volume 3 Issue 1 (2024) 1 https://doi.org/10.36922/gtm.2228