Dechra is highlighting two new published case reports in which horses vaccinated with its strangles vaccine, Strangvac, did not develop clinical strangles during outbreaks on two Swedish yards.

In the first report1, which concerned an outbreak on a busy competition yard after the introduction of a new horse without an isolation period or pre-movement blood ELISA screening for recent S. equi exposure, no horses developed signs of strangles after the second vaccination with Strangvac was administered. 

In the second report2 strangles was confirmed in three unvaccinated and unwell horses and 17 healthy horses on the same yard were subsequently vaccinated with Strangvac. 

Blood samples in this group of vaccinated horses demonstrated that over half had recent exposure to S. equi, despite which, none of them developed strangles.

Bex Glasgow, veterinary surgeon and equine veterinary advisor at Dechra said: “Strangles vaccination, alongside good biosecurity measures, are essential tools in disease prevention and recent studies have also demonstrated its protective effect during outbreak situations.”

Strangles Awareness Week, which is supported by Dechra, takes place from 4 to 10 May 2026.

References

  1. Rask, Erika et al. “Closing the Stable Door on Strangles: Serological Responses of Vaccinated Horses on a Farm Following the Arrival of a New Horse.” Animals : an open access journal from MDPI vol. 15,24 3584. 13 Dec. 2025, doi:10.3390/ani15243584 https://pubmed.ncbi.nlm.nih.gov/41463869/
  2. Gröndahl G, Righetti F, Aspán A, Bjerketorp J, Frosth S, Frykberg L, et al. Reining in strangles: absence of disease in horses vaccinated with a DIVA-compatible recombinant fusion protein vaccine, Strangvac, following natural exposure to Streptococcus equi subspecies equi. Equine Vet J. 2025. https://doi.org/10.1111/evj.70125