As the participants included in this study were most likely highly exposed to SARS-CoV-2 due to their occupation, one could argue that any SARS-CoV-2 CD4 T-cell response was 1) generated during an asymptomatic COVID-19 episode that did not result in a detectable antibody response, 2) reflecting recent exposure to SARS-CoV-2 or 3) corresponding to SARS-CoV-2 cross-reactive memory CD4 T-cells. The gene discussed is CD4; the disease is COVID-19.