IgY technology (egg yolk antibodies) in respiratory medicine: applications and future prospects.

The respiratory system is under strain due to rising infections and diseases affecting millions globally, with antimicrobial resistance, allergens, and the recent pandemic further burdening public health. These challenges emphasize the critical need for support-based adjunct or combination biologics as essential measures for combating disease pathogenesis and optimizing the rational use of antimicrobials and steroids. Passive immunization represents an encouraging approach, with immunoglobulin Y (IgY) derived from hyperimmunized hen egg yolk emerging as a promising, cost-effective, and ethical alternative to conventional mammalian-derived antibodies. IgY technology addresses challenges including stability, process complexity, and antimicrobial resistance, offering practical advantages for human and animal applications. This review examines the application of IgY technology against majorly evolving respiratory pathogens and conditions - influenza virus, SARS-CoV-2, respiratory syncytial virus, Mycobacterium tuberculosis, Streptococcus pneumoniae, and respiratory allergens - highlighting IgY technology's significance as biologics across viral, bacterial, and allergen-driven respiratory diseases. Evidence from the IgY literature is broadly encouraging, demonstrating efficacy in pathogen neutralization, virulence attenuation, and hypersensitivity suppression, particularly through intranasal and oral delivery routes. IgY technology represents an affordable and scalable tool for low- and middle-income countries (LMICs) and beyond. Future priorities should include standardized antibody production protocols, optimized formulations and dosing strategies, rational point-of-care diagnostic integration, and well-designed prospective trials in high-burden settings to bring forth IgY technology's translational potential against prevailing and forthcoming respiratory afflictions.