Sign In
International
Media release
From:
Virology: Monoclonal antibody bebtelovimab is effective against three Omicron sublineages
In laboratory experiments involving 19 monoclonal antibodies, only the recently authorized bebtelovimab was found to be capable of neutralizing all three sublineages of the Omicron variant, according to a study published in Nature. The findings form part of an analysis that suggests that the three sublineages of Omicron are equally divergent from wild-type SARS-CoV-2 and have a similarly comparable effect in reducing the efficacy of current mRNA vaccines.
Following the identification of Omicron (BA.1), continued surveillance has revealed a rise in the prevalence of two further sublineages: BA.1 with an R346K mutation (BA.1 + R346K) and BA.2. The BA.1 + R346K sublineage now accounts for approximately 40% of Omicron sequences globally and between 35–60% of sequences in New Zealand, the UK and the USA. Although the BA.2 sublineage accounts for only around 10% of global sequences, its prevalence is increasing and it is already the dominant form in Denmark, India and South Africa.
David Ho and colleagues investigated the sensitivity of Omicron sublineages to neutralization by sera obtained from individuals who had previously been infected with wild-type SARS-CoV-2 (10 individuals), those who had received either the Pfizer-BioNTech (13) or Moderna (12) vaccines, and participants who had received a further booster shot of either mRNA vaccine (15). The authors found that there was a significant loss of neutralizing activity against BA.1 + R346K and BA.2 compared to wild-type SARS-CoV-2, with reductions comparable to those previously reported for BA.1. However, the decrease in neutralizing activity was less prominent in sera from individuals who had received a booster vaccination.
In laboratory experiments involving 19 monoclonal antibodies, the authors found that BA.2 exhibited marked resistance to 17 of them. This included a 27-fold drop in activity for sotrovimab, which retained appreciable activity against BA.1 and BA.1 + R346K. Of the two remaining antibodies, cilgavimab (on its own or in combination with tixagevimab) retained activity against BA.2 but had no effect against BA.1. Only the recently authorized bebtelovimab remained potent in neutralizing all three sublineages of Omicron.
The authors conclude that as treatment options are narrowed by the emergence of variants, it is imperative that we continue to devise novel strategies to contain SARS-CoV-2.
