Compared with influenza‐vaccinated lean adults, vaccinated adults with obesity have impaired CD4 and CD8 T cell production of key inflammatory cytokines IFN‐γ and granzyme B.151Adults with obesity also have two times greater odds of influenza or influenza‐like illness despite a robust antibody response.164. This evidence concerns the gene CD4 and obesity due to melanocortin 4 receptor deficiency.