Neut­ral­iz­ing anti­bod­ies and T cells against SARS-CoV2 and mutants, espe­cially the delta mutant

We found that SARS-CoV-2 delta mutant anti­body neut­ral­isa­tion was reduced com­pared to the Wuhan wild type (wt), as assessed in a novel inhib­i­tion assay with a fin­ger prick blood drop. Strong T cell responses were present against wt and mutant SARS-CoV2 vari­ants, includ­ing the delta (B.1.617.2) strain, in fully vac­cin­ated indi­vidu­als, whereas they were weaker 1 year after nat­ural infec­tion. Hence, immune responses after vac­cin­a­tion are stronger com­pared to those after nat­ur­ally occur­ring infec­tion, point­ing out the need of vac­cines to over­come the pandemic.