Vivaldi Biosciences to Present DeltaFLU Universal Influenza Vaccine Study Results at ISRV Meeting

Nasal Spray Flu Vaccine in Development to Block Both Infection and Transmission

FORT COLLINS, Colorado and VIENNA, Austria – 7 October, 2025 – Vivaldi Biosciences Inc., a clinical-stage biotechnology company developing nasal spray vaccines for viral respiratory diseases, will present data on its DeltaFLU universal influenza vaccine at the 4th International Society for Respiratory Viruses (ISRV) meeting on Correlates of Protection for Next Generation Influenza Vaccines.

Vivaldi scientist Alaura Hoag will give the presentation, “Cross-Protective Immunity Blocking Transmission by an Intranasal Universal Influenza Vaccine” on October 15 at 2:55 pm at the Aula der Wissenschaften, Vienna. Her talk will cover study results demonstrating broad protection and blocking of virus transmission following intranasal immunization with DeltaFLU. The studies were conducted in ferrets, a well-characterized animal model of influenza infection and immunity in humans. Data from the studies also reveals correlates of protection, immune markers important in the development and evaluation of novel vaccines.                        

DeltaFLU is a nasal spray vaccine with a completely new mode of action. Intranasal immunization with DeltaFLU rapidly induces a broadly protective immune response in the nasal passages, the point of entry of infectious viruses. This rapid mucosal immunity enables protection against a wide range of influenza virus strains and blocking of onward transmission of viruses and disease spread.

“A vaccine that can protect against all influenza virus strains and also block virus transmission would be transformational,” said Bill Wick, CEO of Vivaldi Biosciences. “We are energized by these striking findings and pleased to present these results to the distinguished group of influenza scientists and clinical experts at the ISRV meeting.”

Vivaldi is developing DeltaFLU to protect against all influenza virus strains that cause disease in humans: all seasonal influenza type A and B strains, and emerging influenza virus strains with pandemic potential. DeltaFLU component vaccine strains have been successfully evaluated in four clinical trials. The European Union is funding further clinical development of DeltaFLU under its Horizon Europe Framework Programme.

DeltaFLU is composed of genetically modified influenza vaccine strains from which the NS1 gene is deleted. Deletion of NS1 results in the unique ability of DeltaFLU to induce interferon, conferring a self-adjuvant effect and activating multiple mechanisms of the immune response, including broadly cross-neutralizing antibodies in the nasal passages, systemic antibodies and T cells. Distinct from other nasal spray influenza vaccines composed of live attenuated influenza virus strains, DeltaFLU vaccine strains do not replicate and do not form viral progeny, an important safety advantage.

About Vivaldi Biosciences

Vivaldi is developing intranasal vaccines for superior protection against respiratory diseases. The company’s clinical-stage vaccines are the DeltaFLU universal influenza vaccine, for protection against all influenza type A and B strains; and DelNS1 H5N1 for protection against highly pathogenic avian influenza (HPAI) H5N1 strains, which pose a pandemic threat. 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