Intervacc AB (publ), a Swedish growth company specialising in animal vaccines, has completed the evaluation of a US strain of Streptococcus equi in US horses prior to its use in a clinical trial towards the registration of Strangvac, a vaccine against equine strangles, in the US market.

Strangles, caused by the bacterium Streptococcus equi, is the most frequently diagnosed respiratory disease of horses in the US. The disease is highly contagious and can lead to prolonged disruptions to equine operations, with significant economic consequences.

The strains of S. equi that cause disease in horses around the world are closely related and display high identity at the DNA level. Evaluation of the US S. equi strain called 20-091 at the Gluck Equine Research Center, Kentucky, demonstrated that it behaves identically to the strain used in the successful pivotal clinical trials in Europe.

A perfect match for Strangvac

"That the 20-091 strain behaved similarly to the strain used in the European trials of Strangvac is encouraging news ahead of the upcoming pivotal clinical trial of Strangvac in the US," comments Andrew Waller, CSO of Intervacc. "The majority of strains of S. equi that are recovered from horses in the US, including strain 20-091, are a perfect match for Strangvac, sharing 100% identity to our vaccine."

"The dose of S. equi used in the European trials was >10000-fold higher than that required to infect horses," says Beatrice Sponseller, Clinical Professor at the Gluck Equine Research Center. "The study tested successfully a lower dose of the 20-091 strain that will improve the ability of the clinical trial to simulate field conditions and mimic the natural disease."

"New outbreaks of strangles are reported every day in the US and effective prevention strategies are urgently needed," says Dr. Yosra Helmy, Associate Professor of One Health and Infectious Diseases at the Gluck Equine Research Center. "By establishing a reliable challenge model with a clinically relevant strain, our team has made an important step toward advancing evidence-based protection of horses from strangles in the US."

"We're delighted by the successful outcome of this study and the progress made, which ensures that the targeted launch of Strangvac in the US remains well on track," says Carl-Johan Dalsgaard, CEO of Intervacc. "The proven equivalence between the US and European S. equi strains allows for significant cost savings and time efficiencies."

For more information please contact:  

Carl-Johan Dalsgaard, CEO

Phone: +46 (0)8 120 10 600

E-mail: carl-johan.dalsgaard@intervacc.se

The information was submitted for publication, through the agency of the contact person set out above on May 22, 2026 at 08.30 CET.

About Strangvac

Strangvac is a vaccine against the severe disease equine strangles. The vaccine is approved for sales and marketing in the EU as well as the UK, Iceland, Norway and Liechtenstein, and has been launched in Sweden, Denmark, Finland, the UK, France, Germany, Belgium, the Netherlands, Austria, Spain, Portugal, Ireland, Poland, Slovenia and Italy.

About Intervacc

Intervacc AB is an animal health group that develops vaccines for animals. The company's vaccines and vaccine candidates are based on many years of research at the Karolinska Institute and the Swedish University of Agricultural Sciences. The Intervacc share (Nasdaq: IVACC) is listed on the Nasdaq First North Growth Market. For more information, see intervacc.se

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