The mRNA-1273 vaccine against SARS-CoV-2 elicited high neutralising-antibody titers in phase 1 trial participants and has been shown to be highly efficacious in preventing symptomatic COVID-19 disease and severe disease. The recent emergence of SARS-CoV-2 variants in the United Kingdom (the B.1.1.7 lineage) and in South Africa (the B.1.351 lineage) has led to concerns about increased transmission and the potential of these variants to circumvent immunity elicited by natural infection or vaccination. In this correspondence, the authors used an rVSV-based pseudovirus neutralisation assay to assess the neutralising activity of serum obtained from participants who had received the mRNA-1273 vaccine in the phase 1 trial against the full-length spike protein of the dominant strain in 2020 (D614G), as well as against 20E (EU1), 20A.EU2, N439K-D614G, and mink cluster 5 variants. They observed levels of neutralisation against these variants that were similar to those against the Wuhan-Hu-1 (D614) isolate.
They concluded that protection against the B.1.351 variant conferred by the mRNA-1273 vaccine remains to be determined. Moreover they underlined that their findings underscore the importance of continued viral surveillance and evaluation of vaccine efficacy against new viral variants and may help to facilitate the establishment of correlates of protection in both non-human primates and humans.