THE POST-PANDEMIC INTERPLAY BETWEEN CHRONIC STRESS, MENTAL HEALTH, AND IMMUNE FUNCTION: IMPLICATIONS FOR PUBLIC HEALTH

The COVID-19 pandemic triggered an unprecedented global mental health crisis, resulting in a marked increase in anxiety, depression, sleep disturbances, and chronic stress across diverse populations. According to the World Health Organization (2022), the global prevalence of anxiety and depressive disorders increased by approximately 25% during the first year of the pandemic, disproportionately affecting healthcare workers, young adults, women, and socioeconomically vulnerable groups. Beyond its psychological consequences, accumulating evidence indicates that prolonged stress exposure exerts measurable biological effects through neuroendocrine–immune interactions. Chronic psychological stress contributes to immune dysregulation primarily via sustained activation of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system. Persistent cortisol secretion may initially suppress adaptive immune responses; however, prolonged exposure is associated with glucocorticoid resistance and the development of low-grade systemic inflammation. Post-pandemic studies have documented elevated inflammatory biomarkers – including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) – among individuals experiencing ongoing psychological distress. These alterations have been linked to impaired antiviral immunity, reduced vaccine responsiveness, and increased long-term risk of cardiovascular, metabolic, neuropsychiatric, and autoimmune disorders. Recent findings from psychoneuroimmunology research further demonstrate a bidirectional relationship between inflammation and mental health, whereby inflammatory cytokines may exacerbate depressive and anxiety symptoms through effects on neurotransmitter metabolism, neuroplasticity, and microglial activation. This inflammatory-psychological feedback loop suggests that post-pandemic stress exposure may contribute to sustained population-level disease burden. This review synthesizes current evidence (2020–2025) on the interaction between chronic stress, mental health disturbances, and immune dysfunction in the post-pandemic era. From a public health perspective, the paper highlights the necessity of integrating mental health care into preventive health strategies, in alignment with Sustainable Development Goal 3 (Good Health and Well-being). Community-based resilience programs, stress-reduction interventions, early inflammatory biomarker screening, and interdisciplinary preventive policies may collectively mitigate long-term health consequences and reduce future non-communicable disease burden.