IFNG and infection: SARS‐CoV‐2‐specific T‐cell responses amongst unknown / naïve participants, that is those with no measurable anti‐SARS‐CoV‐2 IgG antibodies and no prior confirmed history of infection, were rare, with 4 of 76 (5·3%) displaying a dual IFN‐γ+/IL‐2+ response and 10 of 76 (13·2%) displaying an IFN‐γ+/IL‐2− response (Figure 2D).