Sun X, Belser JA, Li Z-N, Liu F, Brock N, Pulit-Pe. Prior immunity to seasonal influenza A(H3N2) virus confers varying levels of cross-protection against challenge with clade 2.3.4.4b A(H5N1), A(H7N9), or A(H9N2) virus in a ferret model. Microbiol Spectr. 2026 Apr 30:e0397425
Evaluating how prior immunity to seasonal influenza viruses influences subsequent zoonotic influenza A virus (IAV) infection in animal models is critical for pandemic preparedness. In this study, we investigated the cross-protective effect of pre-existing A(H3N2) immunity in ferrets challenged with three distinct subtypes of zoonotic IAVs: low pathogenic A(H7N9) and A(H9N2) viruses, and highly pathogenic clade 2.3.4.4b A(H5N1) virus. Our results show that A(H3N2) preimmunity conferred some protection against A(H5N1) and A(H9N2) virus infection, as evidenced by more rapid viral clearance in the upper respiratory tract, reduced virus shedding in the nasal wash on select days post-inoculation, and a lowered frequency of viral detection in specific tissues compared with naive animals. In contrast, A(H3N2) preimmunity provided minimal cross-protection against A(H7N9) infection, as weight loss and viral dissemination in tissues were not significantly reduced in A(H3N2) preimmune ferrets relative to naive animals. These findings highlight the variable breadth and magnitude of cross-protection elicited by prior seasonal IAV immunity against zoonotic influenza virus challenges in the ferret model. Seasonal influenza A(H3N2) preimmunity provided differing levels of cross-protection against zoonotic influenza A virus infections in ferrets.
See Also:
Latest articles in those days:
- Birth cohort effects in adults associated with influenza A(H1N1)pdm09 vaccine effectiveness 3 hours ago
- Genetic Characterization of Swine Influenza Viruses in Thailand in 2019-2025 Reveals Novel Reassortants 3 hours ago
- Outbreak dynamics of high pathogenicity avian influenza virus H5N1, clade 2.3.4.4b euBB, in black-headed gulls and common terns in Germany in 2023 3 hours ago
- [preprint]The canine respiratory epithelium is a permissive ecosystem for influenza interspecies transmission and emergence 4 hours ago
- [preprint]Explainable and Calibrated AI for Decoding Host-Adaptive Changes in Influenza A Virus 4 hours ago
[Go Top] [Close Window]


