Developing novel vaccines against highly pathogenic avian influenza (HPAI) in poultry is a vital step in protecting the poultry industry's supply chain

The Department of Agriculture Animal and Plant Health Inspection Service awarded a Cooperative Agreement to Texas A&M Agrilife Research on February 2, 2026, for development of novel Marek's disease virus vector vaccines to protect poultry against highly pathogenic avian influenza. The award obligates $871,330 under the Plant and Animal Disease, Pest Control, and Animal Care program (CFDA 10.025).

The project develops recombinant MDV-1 vaccines using two vectors—MDVDD and CVRM—engineered to express the prefusion form of H5 HPAI protein. The approach addresses limitations in current vaccines by targeting strong immune response, cost-effectiveness, efficacy despite maternal antibodies, compatibility with existing herpesvirus turkey vector vaccines, and support for DIVA (differentiating infected from vaccinated animals) diagnostic strategies. CVRM demonstrates early protection as soon as five days post-vaccination, accelerating intervention timelines in outbreak scenarios.

Texas A&M Agrilife Research, the research division of the Texas A&M University System, performs work at its locations in Texas. The period of performance runs from February 2, 2026, through February 1, 2029. The award protects poultry supply chain continuity by preventing mass culling events driven by HPAI outbreaks, stabilizing production and prices while reducing zoonotic transmission risk to humans and pandemic emergence potential.

HPAI outbreaks often result in the mass culling of birds, severely disrupting production and distribution, and increasing prices for consumers. Effective vaccination helps prevent these outbreaks, maintaining flock health and ensuring a consistent supply of poultry products such as eggs and meat. This continuity is crucial for stabilizing prices and avoiding shortages, which can have ripple effects on food security and economic resilience both locally and globally. Beyond economic concerns, controlling HPAI in poultry through vaccination significantly reduces the risk of zoonotic transmission to humans. This proactive strategy not only safeguards public health but also alleviates pressure on healthcare systems and lowers the likelihood of future influenza pandemics emerging from animal reservoirs. The primary objective of this proposal is to develop innovative marek's disease virus (MDV) vector vaccines to protect poultry against HPAI infections. Current vaccines have limitations, and there is a pressing need for improved options that: (a) elicit strong immune responses; (B) are cost-effective; (C) remain effective despite the presence of maternal antibodies; (D) do not interfere with existing hvtvector vaccines used for other poultry diseases; and (E) support diva (differentiating infected from vaccinated animals) strategies. To meet these goals, we propose using two recombinant MDV-1 viruses, mdvδδ [1] a ND cvrm [2], as vectors for H5 HPAI vaccines. Mdvδδ offers protection comparable to the gold standard MDV vaccine, while cvrm has demonstrated earlier protection, as soon as five days post-vaccination. Our preliminary research confirms both vectors are viable platforms for vaccine development [3]. To induce a broad and effective antibody response, the H5 protein of HPAI will be engineered in its prefusion form and inserted into specific loci of mdvδδ and cvrm. This will involve targeted mutations in the PH-sensitive region [4] and the use of a molecular clamp to stabilize the trimeric HA structure [5]. The project will deliver novel HPAI vaccines which will offer early, single-dose protection, reduce viral shedding, and support diva strategies, benefiting the poultry industry, scientific community, and consumers worldwide.