IL6 and COVID-19: Case-control or cohort studies that investigated the impacts of rs1800795 or rs1800629 on COVID-19 susceptibility, severity, mortality, IL-6, TNF-α, or CRP levels were included after an anonymous review by two independent reviewers and consultations of disagreement by a third independent reviewer.<h4>Results</h4>47 studies (8305 COVID-19 individuals and 17,846 non-COVID-19 individuals) were analyzed.