Alliance for Pandemic Preparedness

May 17, 2021

The Spike Proteins of SARS-CoV-2 B.1.617 and B.1.618 Variants Identified in India Provide Partial Resistance to Vaccine-Elicited and Therapeutic Monoclonal Antibodies

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  • [Pre-print, not peer-reviewed] The SARS-CoV-2 B.1.617 and B.1.618 strains currently circulating in India were found to have specific spike protein mutations (B.1.617 = L452R/E484Q/D614G/P681R, B.1.618 = Δ145-146/E484K/D614G) that were somewhat resistant to neutralization by sera from convalescent individuals, vaccine-elicited antibodies, and therapeutic monoclonal antibodies; but not enough to suggest that current vaccines will not be protective. A study generating pseudoviruses found that those with B.1.617 and B.1.618 spike proteins had an average of 3.9-fold and 2.7-fold reductions in the half maximal inhibitory concentration for convalescent sera and antibodies from the Pfizer-BioNTech and Moderna vaccines, respectively, which the authors suggest could be due to the L452R, E484Q, and E484K mutations. Both variants also had some resistance to the monoclonal antibodies made by Regeneron. 

Tada et al. (May 16, 2021). The Spike Proteins of SARS-CoV-2 B.1.617 and B.1.618 Variants Identified in India Provide Partial Resistance to Vaccine-Elicited and Therapeutic Monoclonal Antibodies. Pre-print downloaded May 17 from https://doi.org/10.1101/2021.05.14.444076