Coronavirus disease 2019 (COVID-19) is a highly contagious viral illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has had a catastrophic effect on the world, resulting in more than 6 million deaths worldwide. After the first cases of this predominantly respiratory viral illness were reported in Wuhan, Hubei Province, China, in late December 2019, SARS-CoV-2 rapidly disseminated worldwide. This compelled the World Health Organization (WHO) to declare it a global pandemic on March 11, 2020.

Even though substantial progress in clinical research has led to a better understanding of SARS-CoV-2, many countries continue to have outbreaks of this viral illness. These outbreaks are primarily attributed to the emergence of mutant variants of the virus. Like other RNA viruses, SARS-CoV-2 adapts with genetic evolution and developing mutations. This results in mutant variants that may have different characteristics than their ancestral strains. Several variants of SARS-CoV-2 have been described during the course of this pandemic, among which only a few are considered variants of concern (VOCs). Based on the epidemiological update by the WHO, 5 SARS-CoV-2 VOCs have been identified since the beginning of the pandemic:

1. Alpha (B.1.1.7): First variant of concern, which was described in the United Kingdom (UK) in late December 2020

2. Beta (B.1.351): First reported in South Africa in December 2020

3. Gamma (P.1): First reported in Brazil in early January 2021

4. Delta (B.1.617.2): First reported in India in December 2020

5. Omicron (B.1.1.529): First reported in South Africa in November 2021

Despite the unprecedented speed of vaccine development against the prevention of COVID-19 and robust global mass vaccination efforts, the emergence of new SARS-CoV-2 variants threatens to overturn the progress made in limiting the spread of this disease. This review aims to comprehensively describe the etiology, epidemiology, pathophysiology, and clinical features of COVID-19. This review also provides an overview of the different variants of SARS-CoV-2 and the guideline-recommended treatment (as of January 2023) for managing this disease.

Marco Cascella declares no relevant financial relationships with ineligible companies.

Michael Rajnik declares no relevant financial relationships with ineligible companies.

Abdul Aleem declares no relevant financial relationships with ineligible companies.

Scott Dulebohn declares no relevant financial relationships with ineligible companies.

Raffaela Di Napoli declares no relevant financial relationships with ineligible companies.