Coronavirus disease 2019 (COVID-19), the highly contagious viral illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a catastrophic effect on the world’s demographics resulting in more than 6 million deaths worldwide as of March 2022, emerging as the most consequential global health crisis since the era of the influenza pandemic of 1918. After the first cases of this predominantly respiratory viral illness were first reported in Wuhan, Hubei Province, China, in late December 2019, SARS-CoV-2 rapidly disseminated across the world in a short span of time, compelling the World Health Organization (WHO) to declare it as a global pandemic on March 11, 2020. Since being declared a global pandemic, COVID-19 has ravaged many countries worldwide and has overwhelmed many healthcare systems. The pandemic has also resulted in the loss of livelihoods due to prolonged shutdowns, which have had a rippling effect on the global economy. Even though substantial progress in clinical research has led to a better understanding of SARS-CoV-2 and the management of COVID-19, limiting the continuing spread of this virus and its variants has become an issue of increasing concern, as SARS-CoV-2 continues to wreak havoc across the world, with many countries enduring a second or third wave of outbreaks of this viral illness attributed mainly due to the emergence of mutant variants of the virus.
Like other RNA viruses, SARS-CoV-2, while adapting to their new human hosts, is prone to genetic evolution with the development of mutations over time, resulting in mutant variants that may have different characteristics than its 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) by the WHO, given their impact on global public health. Based on the recent epidemiological update by the WHO, as of December 11, 2021, five SARS-CoV-2 VOCs have been identified since the beginning of the pandemic:
Alpha (B.1.1.7): first variant of concern described in the United Kingdom (UK) in late December 2020
Beta (B.1.351): first reported in South Africa in December 2020
Gamma(P.1): first reported in Brazil in early January 2021
Delta (B.1.617.2): first reported in India in December 2020
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 including vaccine boosters, the emergence of these new SARS-CoV-2 variants threatens to overturn the significant progress made so far in limiting the spread of this viral illness.
This review article aims to comprehensively describe the etiology, epidemiology, pathophysiology, clinical features, diagnostic methods, and the latest novel therapeutics in the management of COVID-19. This review also briefly provides an overview of the different variants of SARS-CoV-2 and the efficacy of different available vaccines for prevention against COVID-19 and its variants.
Copyright © 2022, StatPearls Publishing LLC.