Advances in the Omicron variant development

Abstract

Severe acute respiratory syndrome coronavirus (SARS‐CoV)‐2 has spread worldwide, leading the World Health Organization (WHO) to declare a pandemic, on 11 March 2020. Variants of concern have appeared at regular intervals—Alpha, Beta, Gamma, Delta, and now Omicron. Omicron variant, first identified in Botswana in November 2021, is rapidly becoming the dominant circulating variant. In this review, we provide an overview regarding the molecular profile of the Omicron variant, epidemiology, transmissibility, the impact on vaccines, as well as vaccine escape, and finally, we report the pharmacological agents able to block the endocellular entry of SARS‐CoV‐2 or to inhibit its viral replication. The Omicron has more than 50 mutations, of which the spike protein has 26–35 amino acids different from the original SARS‐CoV‐2 virus or the Delta, some of which are associated with humoral immune escape potential and greater transmissibility. Omicron has a significant growth advantage over Delta, leading to rapid spread with higher incidence levels. The disease so far has been mild compared to the Delta. The two vaccination doses offer little or no protection against Omicron infection while the booster doses provide significant protection against mild illness and likely offer even greater levels of protection against serious illness. Recently, new oral antiviral agents such as molnupiravir and paxlovid have been approved and represent important therapeutic alternatives to antiviral remdesivir. In addition, monoclonal antibodies such as casirivimab/imdevimab bind different epitopes of the spike protein receptor; is this class of drugs effective against the Omicron variant? However, more research is needed to define whether Omicron is indeed more infectious and whether the vaccines, monoclonal antibodies, and antivirals currently available are effective.

Clinical and Pulmonary CT Characteristics of Patients Infected With the SARS-CoV-2 Omicron Variant Compared With Those of Patients Infected With the Alpha Viral Strain

“…This may also explain why the Omicron variant is transmitted from person to person more rapidly than the Alpha strain. However, we should note that the severity of COVID-19 in humans is determined by both viral replication and the host immune response to infection, which may lead to the dysregulation of the innate immune system ( 20 ).…”

Vitamin D Endocrine System and COVID-19: Treatment with Calcifediol

“…In conclusion, we, therefore, propose to consider using calcifediol at the doses described for the rapid correction of 25OHD deficiency in all patients in the early stages of the disease, in association, if necessary, with the new oral antiviral agents, such as molnupiravir, fluvoxamine, plitidepsin, paxlovid, etc. [106,107].…”

Efficacy of SARS-CoV-2 Vaccination in Dialysis Patients: Epidemiological Analysis and Evaluation of the Clinical Progress

“…Our experience further emphasizes the essential role of thorough counseling operated by health personnel, especially in a clinically and psychologically fragile population whose choices are often conditioned by families and caregivers [ 42 ]. The period analyzed in this study was that of the fourth pandemic wave in Italy, characterized by the appearance of the highly contagious omicron variant that quickly replaced the delta, as confirmed by sequencing analysis on infected inhabitants of the Romagna region, as well as by national and international data [ 43 ]. The most remarkable finding was the lower rate of COVID-19-related complications, severe symptoms, hospitalizations and deaths observed after vaccine introduction in comparison with the initial pandemic phases, even in vulnerable subjects with advanced age and pre-existing chronic conditions.…”