CXCL8 and susceptibility to pneumonia measurement: Retrospective cytokine analysis (pre-pandemic 2018–2019 vs. post-pandemic 2023–2024) revealed post-pandemic suppression of IL-6 (6.12 vs.3.82 pg/mL) and IL-8 (37.98 vs. 18.35 pg/mL), with resurgence in 2024, particularly in pediatric and pneumonia cases (P<0.05).