In the context of COVID-19, kefir demonstrated antimicrobial and immunomodulatory activity by downregulating the expression of pro-inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ) [61]. Here, TNF is linked to COVID-19.