Immunologic resilience and COVID-19 survival advantage

Area of Science:

• Immunology
• Infectious Disease Epidemiology
• Sex Differences in Health

Background:

• Severe COVID-19 risk varies by age and is higher in males.
• Sex-biased differences in COVID-19 susceptibility may stem from 'immunologic resilience' (IR) deficits.

Purpose of the Study:

• To investigate if pre-existing or infection-induced IR deficits predict COVID-19 mortality.
• To analyze the relationship between IR metrics and COVID-19 outcomes.

Main Methods:

• Quantified IR using immune health grades (IHG-I to IHG-IV) based on T-cell counts and gene expression signatures.
• Examined IR metrics in a prospective COVID-19 cohort (n=522) for 30-day mortality.
• Validated IR metrics in non-COVID-19 cohorts (n=13,461) to link pre-COVID-19 status to outcomes.

Main Results:

• IHG-I (best T-cell equilibrium) was common in healthy females; SARS-CoV-2 infection reduced IHG-I, especially in males.
• Presentation with IHG-I correlated with 88% lower mortality, reduced hospitalization, lower IL-6, faster viral clearance, and survival-associated gene signatures.
• IR-preserving metrics in other cohorts associated with resistance to influenza/HIV and lower long-term mortality, particularly in females.

Conclusions:

• Preserving immunocompetence with controlled inflammation defines IR, linked to longevity and AIDS resistance.
• A male-biased decline in IR before or during SARS-CoV-2 infection independently increases severe COVID-19 risk.