Clinical virology and effect of Covid-19 vaccination and monoclonal antibodies against highly infectious SARS- CoV-2 omicron sub variant BF.7 (BA.5.2.1.7): A systematic review

Over time, the SARS-CoV-2 virus has acquired several genetic mutations, particularly on the receptor-binding domain (RBD) spike glycoprotein. The Omicron variant is highly infectious, with enhanced immune escape activity, and has given rise to various sub-lineages due to mutations. However, there has been a sudden increase in COVID-19 reports of the Omicron subvariant BF.7 (BA.2.75.2), which has the highest number of reported cases, accounting for 76.2% of all cases worldwide. Hence, the present systematic review aimed to understand the viral mutations and factors associated with the increase in the reports of COVID-19 cases and to assess the effectiveness of vaccines and mAbs against the novel Omicron variant BF.7. The R346T mutation on the spike glycoprotein RBD might be associated with increased infection rates, severity, and resistance to vaccines and mAbs. Booster doses of COVID-19 vaccination with bivalent mRNA booster vaccine shots are effective in curtailing infections and decreasing the severity and mortality by enhancing the neutralizing antibodies (Abs) against the emerging Omicron subvariants of SARS-CoV-2, including BF.7 and future VOCs. •The SARS-CoV-2 Omicron (B.1.1.529) variant was identified later in November 2021, with enhanced immune escape.•Omicron subvariant BF.7 (BA.2.75.2) is a novel highly infectious subvariant of Omicron.•The R346T mutation on the spike glycoprotein RBD Omicron of BF.7 variant is associated with increased infectiousness, and serious illness.•Current evidence has shown that Additional booster dose vaccination, preferably with bivalent mRNA vaccines has been associated with an increased immunogenicity against highly infectious SARS-CoV-2 Omicron subvariants including BF-7, but are resistant to majority of currently available mAbs.