Fig. 7: Conceptual illustration showing the minimal presence of effective mucosal immunity in the lung of intramuscular mRNA-vaccinated individuals without or with prior SARS-CoV-2 infection, and its effective induction by inhaled aerosol immunization with a next-generation COVID-19 vaccine. | Nature Communications

Fig. 7: Conceptual illustration showing the minimal presence of effective mucosal immunity in the lung of intramuscular mRNA-vaccinated individuals without or with prior SARS-CoV-2 infection, and its effective induction by inhaled aerosol immunization with a next-generation COVID-19 vaccine.

From: Induction of lung mucosal immunity by a next-generation inhaled aerosol COVID-19 vaccine: an open-label, multi-arm phase 1 clinical trial

Fig. 7

Top: Intramuscular mRNA vaccination in uninfected and previously infected individuals generates strong systemic antibodies against spike protein and RBD but weak antigen-specific mucosal antibodies and T cells in the lung or lower respiratory tract. Bottom: Inhaled aerosol delivery of a next-generation multiantigenic ChAd-vectored COVID-19 vaccine deposits the vaccine particles of 2–5 µm deep into the major airways, inducing tripartite respiratory mucosal immunity consisting of persisting tissue-resident memory cytotoxic CD8 T cells, trained innate immunity in airway macrophages, and virus-neutralizing antibodies. Such all-around mucosal immunity in the lung offers optimal, durable protection against SARS-CoV-2 infection, particularly in high-risk human populations. Created in BioRender. Kang, A. (2025) https://BioRender.com/bt5wx05.

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