The CEO of Eli Lilly, the manufacturer of bamlanivimab, has told news outlets that he believes bamlanivimab is effective against the coronavirus variant found in the UK. However, he stated bamlanivimab's efficacy against the South Africa strain may be of concern. The South Africa variant has more dramatic mutations to the spike protein, and it could theoretically evade bamlanivimab. [1], [2], [3]

A spokesperson from Regeneron, the manufacturer of casirivimab and imdevimab, states that data, including data from preliminary neutralization analyses and against other currently circulating variants, indicates the antibody cocktail will remain effective against new strains. However, one of the antibodies in the cocktail may be susceptible to the South African variant of COVID-19. While the other is expected to work, the efficacy of casirivimab and imdevimab against the South African strain is unknown. The antibody cocktail was designed to combat new variants, as demonstrated by in vitro studies. [1], [2], [3], [4], [5]