SARS-CoV-2 Lambda Variant Remains Susceptible to Neutralization by mRNA Vaccine-elicited Antibodies and Convalescent Serum

ABSTRACT

The SARS-CoV-2 lambda variant (lineage C.37) was designated by the World Health Organization as a variant of interest and is currently increasing in prevalence in South American and other countries. The lambda spike protein contains novel mutations within the receptor binding domain (L452Q and F490S) that may contribute to its increased transmissibility and could result in susceptibility to re-infection or a reduction in protection provided by current vaccines. In this study, the infectivity and susceptibility of viruses with the lambda variant spike protein to neutralization by convalescent sera and vaccine-elicited antibodies was tested. Virus with the lambda spike had higher infectivity and was neutralized by convalescent sera and vaccine-elicited antibodies with a relatively minor 2.3-3.3-fold decrease in titer on average. The virus was neutralized by the Regeneron therapeutic monoclonal antibody cocktail with no loss of titer. The results suggest that vaccines in current use will remain protective against the lambda variant and that monoclonal antibody therapy will remain effective.