Vivaldi Biosciences Granted U.S. Patent for Universal Influenza Vaccine

Nasal Spray Universal Flu Vaccine in Clinical Development for Both Protection and Blocking of Disease Transmission

FORT COLLINS, Colorado and VIENNA, Austria – November 19, 2025 – Vivaldi Biosciences Inc., a clinical-stage biotechnology company developing nasal spray vaccines for viral respiratory diseases, announced today that the United States Patent and Trademark Office has issued U.S. Patent Number 12,447,204 for its DeltaFLU universal influenza vaccine. DeltaFLU is in clinical development for protection against infection and transmission of all influenza type A and B virus strains, including strains with pandemic potential.

Vivaldi’s DeltaFLU universal influenza vaccine is composed of genetically modified influenza vaccine strains lacking the gene for nonstructural protein 1 (NS1). Deletion of NS1 (DelNS1) results in the ability of DeltaFLU to rapidly induce interferon, a signaling protein produced by the body to activate the immune response. Immunity generated in the nasal passages, in the form of broadly-acting antibodies and T cells, creates a first line of defense at the point of entry to prevent virus infection and transmission. DeltaFLU also generates a broadly protective systemic immune response. DeltaFLU vaccine strains do not replicate in humans and are not shed by recipients, providing important safety advantages.

DeltaFLU uses the unique immune-stimulating properties of DelNS1 vaccine strains in a prime-boost immunization regimen that directs the immune response to conserved regions of the stem portion hemagglutinin (HA), a glycoprotein on the viral membrane. The specific combination of DelNS1 strains in the two-component DeltaFLU vaccine directs antibodies to all forms of HA stems of influenza type A and B viruses. This pan-influenza response enables protection against all 20 influenza virus subtypes and their many variants that cause disease in humans.

Available vaccines for seasonal influenza are designed to protect against only a few selected influenza virus strains. Influenza viruses mutate constantly, requiring annual attempts to match influenza vaccines to the strains expected to dominate in the coming flu season. Mismatches between vaccines and circulating strains frequently occur, resulting in poor protection.

“Securing this U.S. patent underscores the scientific innovation behind our DelNS1-based heterologous prime-boost strategy. It validates a fundamentally new way to drive broad mucosal and systemic immune responses—an essential step toward a vaccine that can outpace influenza’s variability,” commented Thomas Muster, PhD, Chief Scientific Officer and inventor of the patented prime-boost vaccine. “DeltaFLU brings together two breakthrough concepts in influenza vaccination: deletion of the NS1 gene, which enhances both immunogenicity and safety, and a heterologous prime-boost regimen designed to achieve universal protection.”

Ongoing clinical development of DeltaFLU is funded by the European Union's Horizon Europe Research & Innovation program, under grant agreement No. 101080692. DeltaFLU component vaccine strains previously have been evaluated in four clinical trials. The vaccine strains induced a broad immune response and were well-tolerated, with no safety signals. Vivaldi has demonstrated in preclinical studies that DeltaFLU blocks transmission of influenza type A and B virus strains, and protects against challenge with broadly divergent influenza type A and B viruses.

About Vivaldi Biosciences

Vivaldi is developing intranasal vaccines for superior protection against influenza and other respiratory diseases, based on its DelNS1 technology platform. The company’s clinical-stage vaccines are DeltaFLU universal influenza vaccine, for protection against all influenza A and B strains; and DelNS1 H5N1, a Phase 2-ready vaccine for broad protection against highly pathogenic influenza strains with pandemic potential. The company’s Delta-19 combination vaccine for Covid-19 and influenza is in preclinical development. Vivaldi’s Vero cell-based vaccine manufacturing system uses patented advances in production and purification for high yields and excellent purity. Vivaldi is a venture-backed company with operations at the Research Innovation Center at Colorado State University, Fort Collins, Colorado, and in Vienna, Austria. NGN Capital LLC is the company’s lead investor. Learn more at www.vivaldibiosciences.com. Connect with Vivaldi Biosciences on Linkedin and Twitter.

Contact

Bill Wick, CEO, Vivaldi Biosciences

Tel: +1 650-400-8915

bill.wick@vivaldibiosciences.com

Forward-Looking Statements

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