SARS-CoV-2 emerging Omicron subvariants with a special focus on BF.7 and XBB.1.5 recently posing fears of rising cases amid ongoing COVID-19 pandemic

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron versions have been the sole one circulating for quite some time. Subvariants BA.1, BA.2, BA.3, BA.4, and BA.5 of the Omicron emerged over time and through mutation, with BA.1 responsible for the most severe global pandemic between December 2021 and January 2022. Other Omicron subvariants such as BQ.1, BQ.1.1, BA.4.6, BF.7, BA.2.75.2, XBB.1 appeared recently and could cause a new wave of increased cases amid the ongoing COVID-19 pandemic. There is evidence that certain Omicron subvariants have increased transmissibility, extra spike mutations, and ability to overcome protective effects of COVID-19 neutralizing antibodies through immunological evasion. In recent months, the Omicron BF.7 subvariant has been in the news due to its spread in China and a small number of other countries, raising concerns about a possible rebound in COVID-19 cases. More recently, the Omicron XBB.1.5 subvariant has captured international attention due to an increase in cases in the United States. As a highly transmissible sublineage of Omicron BA.5, as well as having a shorter incubation time and the potential to reinfect or infect immune population, BF.7 has stronger infection ability. It appears that the regional immunological landscape is affected by the amount and timing of previous Omicron waves, as well as the COVID-19 vaccination coverage, which in turn determines whether the increased immune escape of BF.7 and XBB.1.5 subvariants is sufficient to drive new infection waves. Expanding our understanding of the transmission and efficacy of vaccines, immunotherapeutics, and antiviral drugs against newly emerging Omicron subvariants and lineages, as well as bolstering genomic facilities for tracking their spread and maintaining a constant vigilance, and shedding more light on their evolution and mutational events, would help in the development of effective mitigation strategies. Importantly, reducing the occurrence of mutations and recombination in the virus can be aided by bolstering One health approach and emphasizing its significance in combating zoonosis and reversal zoonosis linked with COVID-19. This article provides a brief overview on Omicron variant, its recently emerging lineages and subvairants with a special focus on BF.7 and XBB.1.5 as much more infectious and highly transmissible variations that may once again threaten a sharp increase in COVID-19 cases globally amid the currently ongoing pandemic, along with presenting salient mitigation measures.

Insight into vaccination and meteorological factors on daily COVID-19 cases and mortality in Bangladesh

“…In late December 2019, a disease having flu-like symptoms was first discovered in some patients in the Wuhan city of China ( Dhama et al, 2022 ; A. Islam et al, 2022a , Islam et al, 2022b , Islam et al, 2022c , Islam et al, 2022d ).…”

Global threat from novel SARS-CoV-2 variants, BF.7, XBB.1.5, BQ.1, and BQ.1.1: variants of concern?

“…Globally, the recent surge in COVID-19 cases in China and the United States of America (USA) was brought about by the novel BF.7 and XBB.1.5 variants that have garnered considerable public attention [1]. Commonly reported symptoms are illustrated in Fig.…”

“…XBB.1.5 is regarded as a hybrid of pre-existing BA.2.10.1 and BA.2.75 variants [7]. Preliminary studies on the XBB.1.5 variant underscore its higher infectivity, rapid transmission, and immune evasion capacity than other Omicron sublineages, especially in populations not previously exposed to omicron variants [1]. However, there is a paucity of evidence supporting the higher infectivity rates and immune evasion capacity of variant XBB.1.5, and the surge in infections is heavily dependent on the geographical and immunological landscape, vaccination coverage, and governmental norms.…”

“…The receptor-binding domain (RBD) of the XBB.1.5 variant demonstrates rare mutations, such as F486P and G252V, which account for its adherence to host cells and potential immune evasion. However, its contribution to disease severity and mortality must be determined [1,8]. Additionally, in order to address the potential of immune evasion of any novel variant, the authors believe that all potential antigenic sites and/or epitopes must be identified and then tested for immune evasion in their respective populations, owing to differences in population immunity.…”

“…Immunization and vaccine booster doses, especially in vaccination drives, confer protection to a large population against the current and upcoming variants, thereby reducing the number of hospitalizations, disease severity, fatalities, and long-term complications [1]. With the immunity waning rapidly, recurrent booster doses have been advised, thereby defeating the rationale of vaccine development and vaccination.…”