The ongoing spread of highly pathogenic avian influenza (HPAI) H5N1 virus poses a serious threat to the poultry industry, a vital component of U.S. Agriculture

The Department of Agriculture Animal and Plant Health Inspection Service awarded a $2,000,000 cooperative agreement to Kansas State University on February 2, 2026, to develop a live-attenuated H5N1 poultry vaccine and companion diagnostic tool under the Plant and Animal Disease, Pest Control, and Animal Care program (CFDA 10.025).

Kansas State University will assess the safety, immunogenicity, and efficacy of a recombinant vaccine designated BPI3VC-H5N1 in chickens. The vaccine is engineered to express key protective antigens from highly pathogenic avian influenza H5N1 on a bovine parainfluenza virus type 3 vector, allowing replication in primary chicken embryo fibroblast cells. The university will also develop and validate a lateral flow device diagnostic capable of differentiating infected from vaccinated animals by detecting immune responses specific to both the vaccine vector and H5N1 antigens. Challenge studies will assess protective efficacy, viral shedding, and transmission. The vaccine is ready for scale-up in readiness for administration through in ovo injection, spray application, or water delivery to day-old chicks and pullets.

The period of performance extends from February 2, 2026, through February 1, 2029. Work is performed in Kansas.

The virus endangers not only poultry production, but also food security and public health. Thus, development of safe, effective, scalable, and affordable countermeasures is urgently needed to protect this critical sector. We have developed a novel live-attenuated vaccine platform based on bovine parainfluenza virus type 3, genotype C (BPI3VC), engineered to express key protective antigens from H5N1. The vector displays hemagglutinin (HA), neuraminidase (NA), and matrix protein 2 ectodomain (M2E) on the surface of infected cells, and nucleoprotein (NP) in the cytosol. The recombinant vaccine, designated BPI3VC-H5N1, replicates efficiently in primary chicken embryo fibroblast cells and expresses the transgenes robustly, as confirmed using convalescent H5N1 sera. Since BPI3VC is not a chicken pathogen, IT allows for the development of a lateral flow device (LFD) capable of differentiating infected from vaccinated animals (DIVA) by detecting immune responses specific to both the vaccine vector and H5N1 antigens. This project has two main aims: 1) to assess the safety, immunogenicity, and efficacy of the BPI3VC-H5N1 vaccine in chickens; and 2) to develop and validate a companion DIVA diagnostic LFD. The vaccine is ready for scale-up in readiness for in OVO vaccination, and administration to day-old chicks and pullets through spray or water. Challenge studies with contemporary HPAI H5N1 will assess protective efficacy, viral shedding, and transmission. In parallel, we will develop an LFD incorporating the BPI3VC fusion (F) protein and H5 HA antigen as dual test lines. The device's diagnostic performance will be validated using study and field samples. The anti cipated outcomes include delivery of a H5N1 vaccine for poultry and a DIVA-compatible LFD diagnostic tool. The vaccine's flexibility for administration in OVO, via spray, or water, makes IT well suited for integration into existing hatchery and farm-based mass vaccination systems. Early immunization will provide protection to broilers, layer chicks, and pullets, ensuring broad applicability across production types. Beneficiaries include poultry hatcheries, farmers, allied service providers, consumers of poultry products, and export markets dependent on disease-free certification.