Filamentous morphology of influenza A virus confers enhanced stability in aerosols.

Summary

Filamentous IAVs resist physicochemical inactivation in submicron aerosols, particularly at 80% RH and low pH, and retain infectivity advantages under mucus and neutralizing antibodies in primary human airway cultures. Morphology thus directly contributes to airborne stability and epithelial infectivity.

Key Findings

• Filamentous IAVs exhibited enhanced stability in submicron aerosols at 80% relative humidity and in bulk solutions mimicking increased salinity.
• Acidic conditions caused slower infectivity decay for filamentous vs spherical virions in both aerosols and bulk solutions.
• In primary human airway cultures, filamentous IAVs showed infectivity advantages under mucosal immune pressures (neutralizing antibodies, mucus).

Clinical Implications

Highlights the potential for filamentous-dominant strains to persist in indoor aerosols and evade mucosal defenses, suggesting implications for ventilation standards, humidity control, and personal protective strategies.

Limitations

• Laboratory aerosol systems may not fully recapitulate real-world indoor environments.
• Morphological distribution depends on strain and growth conditions, potentially limiting generalizability.

Future Directions

Assess morphology distributions in clinical isolates over time, quantify impacts of ventilation/filtration and humidity in built environments, and model transmission risk incorporating morphological heterogeneity.