Intravenous immunoglobulin therapy in viral infections: Lessons learned from COVID-19

Area of Science:

• Immunology
• Virology
• Pharmacology

Background:

• Intravenous immunoglobulin (IVIg) has known antiviral and immunomodulatory effects.
• Its precise role in managing viral infections, including COVID-19, requires further clarification.

Purpose of the Study:

• To review IVIg mechanisms of action.
• To evaluate the clinical relevance of IVIg in viral diseases, focusing on COVID-19.

Main Methods:

• A structured narrative literature review was performed.
• Searches included PubMed (MEDLINE) and reference lists of relevant publications up to early 2026.
• Evidence was synthesized qualitatively after title, abstract, and full-text screening.

Main Results:

• IVIg utilizes multiple mechanisms: Fab-mediated neutralization, Fc receptor modulation, complement inhibition, cytokine regulation, and FcRn-mediated IgG clearance.
• In immunodeficient patients, IVIg provides passive immunity and aids viral control.
• In severe infections like COVID-19, IVIg's benefits may stem from immunomodulation rather than direct antiviral action, with varied clinical results.

Conclusions:

• IVIg is a context-dependent immunomodulatory therapy, not a universal antiviral.
• Clinical efficacy hinges on matching IVIg mechanisms with disease immunopathology.
• Biomarker-guided, stage-specific approaches are crucial for optimizing IVIg use.