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Nasal Flu Spray: A Different Immune Battleground?
30 Apr
Summary
- Nasal spray flu vaccine activates immunity within nasal tissues.
- This localized response is undetectable in adult blood samples.
- Findings may accelerate development of needle-free vaccines.
New research published on April 29, 2026, in Science Translational Medicine indicates that the nasal spray flu vaccine, FluMist, operates differently than traditional flu shots. Unlike injected vaccines that circulate antibodies in the blood, FluMist appears to create an immune response directly within the nasal tissue in adults. This localized immunity in the upper airways was previously undetectable in blood tests, leading scientists to question its efficacy.
Researchers employed a new deep nasal swab method to gather specimens from adults before and after receiving FluMist. They observed a significant and durable increase in flu-fighting immune cells within the nasal passages, persisting for at least six months. This contrasts with flu jabs, which boosted antibodies in the bloodstream but did not generate a comparable upper airway immune cell response. These insights could refine how the effectiveness of new nasal vaccines is assessed, potentially accelerating the development of needle-free alternatives.
