TNF and infection: Bouayed and Bohn (47) proposed a “Two-Hit Hypothesis” that suggest a combination of poor lifestyle and environmental factors in early life (first hit), and disease and infection later in life (second hit) may upregulate pro-inflammatory processes such as increased release of cytokines and inflammatory markers such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IF)-γ that may explain why certain individual show worsened COVID-19 symptoms compared to others.