Intervacc AB (publ) today announces that after the first 100.000 doses of Strangvac were sold in the EU and UK, only 3 cases of confirmed S. equi infection were reported in horses that completed their primary vaccination.
Strangles, a potentially lethal infection caused by Streptococcus equi, is the most frequently diagnosed infectious disease of horses worldwide. The bacteria are highly contagious, and infection is spread via direct, or indirect contact with infected horses or contaminated food, water or equipment.
Vaccination is an important tool to control the disease, including to protect horses in outbreak situations. Strangvac, a recombinant protein vaccine, has been available on the European markets since 2022 and Intervacc has now investigated the outcome following of the first 100.000 doses.
The detailed analysis of pharmacovigilance data following the first 100.000 doses identified 19 reports of suspected lack of expected efficacy, where horses developed signs of strangles after they had received their primary vaccination. Only 3 of these cases were confirmed to be due to infection with S. equi, a calculated incidence of 0,006%. It is not known how many of the vaccinated horses were exposed to S. equi, but a large proportion where from yards with an ongoing outbreak, which dramatically increases the risk of catching the infection.
This high efficacy is thanks to Intervacc's recombinant vaccine technology, which utilizes 3 proteins consisting of 8 antigens that are crucial for the bacteria to infect horses. By presenting multiple key antigens Strangvac produces a strong immune response that attacks multiple mechanisms used by the bacteria to cause disease.
"Around 3% of horses in the UK are vaccinated currently against strangles, often in response to outbreaks of disease where the risk of infection is high," says Andrew Waller, CSO of Intervacc. "However, in the past two years only one of 920 diagnoses of strangles in the UK occurred in a horse that had received the two primary vaccination doses of Strangvac."
"The nearly 100% protection demonstrated in the real-world data set shows the strength of the vaccine and that prophylaxis is effective", says Carl-Johan Dalsgaard, CEO of Intervacc. "It also validates our platform where the precision in selecting the crucial antigens for infection is key to the performance of the vaccines."
Carl-Johan Dalsgaard, CEO
Phone: +46 (0)8 120 10 600
Email: carl-johan.dalsgaard@intervacc.se
The information was submitted for publication, through the agency of the contact person above, on 3 November 2026 at 08:30 CET.
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.
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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