Pyles, K., et al. Intranasal and intramuscular H5-Matrix-M nanoparticle vaccines protects against highly pathogenic H5N1 influenza virus in mice. NPJ Vaccines, 2026 Jul 10. PMID: 42431930

This study evaluates the immunogenicity and protective efficacy of a recombinant H5 hemagglutinin (HA) nanoparticle vaccine adjuvanted with Matrix-M, administered either intranasally or intramuscularly, against a highly pathogenic clade 2.3.4.4b H5N1 influenza virus in mice. 

The research demonstrates that both routes induce robust systemic and mucosal antibody responses, including neutralizing antibodies, and confer complete protection against lethal H5N1 challenge, with intranasal delivery additionally eliciting mucosal IgA antibodies that reduce viral replication in the upper respiratory tract. This highlights the potential of nanoparticle-based mucosal vaccines to provide broad protection, especially in pre-immune populations or during pandemics. The uniqueness of this paper lies in its comparison of administration routes and its focus on a recombinant protein vaccine capable of inducing strong mucosal immunity, a critical feature for controlling respiratory viruses and potentially reducing transmission.

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