The research tracked the longitudinal concentrations and trajectories of 21 cytokines and chemokines, including IL-2RA, IL-7, IL-8, IL-15, IL-29 (interferon-λ), inducible protein-10, monocyte chemoattractant protein-1, and TNF-α, and showed that fully vaccinated individuals displayed significantly lower concentrations of these markers than unvaccinated individuals during the onset phase of symptomatic COVID-19 [67]. This evidence concerns the gene CXCL8 and COVID-19.