Clinical Virology and Effect of Vaccination and Monoclonal Antibodies against SARS-CoV-2 Omicron Sub Variant BF.7 (BA.5.2.1.7): A systematic review

Abstract

Since its identification in late 2019 the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) In Wuhan, China, by the World Health Organization (WHO), which cause the coronavirus disease 2019, it is rapidly spreading, resulting in the global pandemic. As of 19 December 2022, more than 64 million confirmed cases and 6,645,812 deaths have been reported across the world. Over time, the SARS-CoV-2 acquired genetic mutations resulting in multiple types of SARS-CoV-2 variants and subvariants that have been confirmed. The Omicron (B.1.1.529) variant was identified later in November 2021, with enhanced immune escape and was followed with various sublineages due to mutations in the spike protein of the SARS-CoV-2. However, rapid resurge in COVID-19 reports by Omicron subvariant BF.7(BA.2.75.2) in China and other countries, alarming global threat. The present systematic review was conducted using "Omicron" AND "BA.5.2.1.7" OR "BF.7" in Pub Med, Google Scholar and MedRXiv database and grey literature from the authentic database and websites . We have identified a total of 14 published studies. We have reviewed all the eligible available studies to understand the viral mutations, factors associated with increase in the reports of COVID-19 cases in china and across the world and to evaluate the effectiveness of vaccination and monoclonal antibodies against BF.7 variant

BF.7 Omicron subvariant (BA.5.2.1.7) posing fears of a rise in COVID-19 cases again: a critical appraisal and salient counteracting strategies

“…Recently, the Omicron subvariant BF.7 (BA.5.2.1.7) has outcompeted the earlier different lineages, sublineages, and subvariants of Omicron (B.1.1.529), including BA.2, BA.3, BA.1, BA.1.1, BA.2.12.1, BA.2.75, BA.2.75.2, BA.4, BA.4.6, BA.5, BQ.1, and BQ.1.1 (BA.4/5), owing to possessing additional genomic mutation, higher transmissibility, and significant immune evasion properties to overpower protection rendered by neutralization antibodies of coronavirus disease 2019 (COVID-19) vaccines and boosters as well as the efficacy of immunotherapeutics [antibodies, monoclonal antibodies (mAbs)], and potentially increasing reinfections 1 – 5 . BF.7 (BA.5.2.1.7) is a sublineage of Omicron variation BA.5.…”

“…BF.7 (BA.5.2.1.7) is a sublineage of Omicron variation BA.5. Of note, Chinese cities are afflicted by BF.7, which is spreading rapidly in Beijing, and eventually this subvariant has also been reported from the USA, Brazil, UK, Belgium, Germany, France, China, Denmark, Norway, Mongolia, Japan, India, and other countries, raising alarming concerns throughout the world 1 , 6 , 7 .…”

“…Chinese strategy to tackle the pandemic seems to have failed on numerous fronts, from possibly the usage of less effective vaccines to the zero-COVID policy, inadequate immunity from past severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, which probably did not sufficiently allow achieving herd immunity in the population, and lead to BF.7’s high transmissibility in the country. Further, China has a high population of the elderly, and many of them have not received the desired booster doses 1 , 6 . The initial symptoms of BF.7 subvariant, like fever, cough, sore throat, running nose, fatigue, vomiting, and diarrhea, are similar to other Omicron subvariants.…”

“…The initial symptoms of BF.7 subvariant, like fever, cough, sore throat, running nose, fatigue, vomiting, and diarrhea, are similar to other Omicron subvariants. In countries like India, as the majority of the population has acquired hybrid immunity, both from natural infection of SARS-CoV-2 and Omicron subvariants as well as vaccinations, therefore BF.7 is manifesting differently and causing mild symptoms 1 , 7 . Hybrid immunity against COVID-19 can reduce hospitalization and disease severity.…”

“…BF.7 is a more dangerous subvariant as it spreads rapidly due to high transmissibility and low incubation period. As per the comparative significant higher R 0 value, one BF.7 infected person may spread the virus to nearly 10–18 persons owing to novel mutations gained in the spike protein, possessing a higher affinity for human ACE2 receptor and revealing increased expression of the receptor-binding domain 1 . BF.7 subvariant has shown a 4.4-fold higher neutralization resistance than Omicron as it carries an additional specific mutation (R346T) in viral spike protein, exhibiting that the earlier vaccination may not be quite effective owing to higher antibody-mediated immune evasion than the original D614G variant 1 , 5 .…”