Top West Nile Vaccines UK 2026: Equilis West Nile & Proteq West Nile
Published on Thursday, 26 February 2026
West Nile virus remains a genuine concern for equine health across the United Kingdom, particularly during the warmer months when Culex mosquitoes are most active. Whether you manage horses in southern England, the Midlands, Scotland, or further afield, a clear vaccination strategy is essential to protect animals from this potentially serious neurological disease. The core equine vaccines category covers practical immunisation supplies designed for routine prevention and rapid response. In the UK market owners, livery yard managers, and equine veterinarians choose between a small number of licensed West Nile products that differ by formulation, dosing schedule, cold-chain needs, and documented field performance. Some vaccines are inactivated and offer a well established safety profile, while others use recombinant technology to produce a rapid immune response. Buyers tend to prioritise proven efficacy, ease of storage and handling on yard, compatibility with pregnancy or youngstock, clear booster intervals, and a vaccine that fits local risk assessments and travel or competition requirements. Cost, veterinary support, and availability through UK veterinary practices also shape consumer preference, making clear product information and an individual horse risk assessment vital when choosing the right West Nile vaccine.
Top Picks Summary
Equilis West Nile
Equilis West Nile (MSD Animal Health) is an inactivated vaccine with a strong safety and tolerability record in the UK and wider European market, making it a go-to option for owners seeking predictable, established protection through the mosquito season. It is given as a two-dose primary course from six months of age, followed by annual boosters. Compared with the recombinant canarypox approach of Proteq West Nile, Equilis offers broad immunogenicity with straightforward dosing and is typically the more cost-effective of the two licensed options.
Proteq West Nile
Proteq West Nile (Boehringer Ingelheim) uses recombinant canarypox-vectored technology (strain vCP2017) that expresses West Nile virus preM/E proteins, stimulating both cellular and humoral responses and supporting a faster-onset immunity for at-risk horses in the UK. It is licensed from around five months of age, given as a two-dose primary course followed by annual boosters. It usually sits at a premium versus inactivated options like Equilis West Nile, a cost some owners accept for the recombinant platform's immunological profile.
Scientific evidence and practical guidance
A growing body of clinical trials, licence dossiers, and real-world surveillance supports the use of licensed West Nile vaccines for horses. Research demonstrates that vaccinated horses develop protective antibody responses and that vaccination reduces the risk of clinical disease and severe neurological outcomes. Different vaccine technologies — inactivated versus recombinant — each have strengths shown in immunogenicity and safety studies. Licensing and post-licence monitoring in Europe and North America also provide data on safety in pregnant mares, foals, and previously unvaccinated adult horses. Veterinary guidance applies these findings to local UK conditions, advising primary course schedules and booster timing that balance immunity duration with on-yard practicality.
Field and clinical trials show most licensed West Nile vaccines induce high rates of seroconversion after the recommended primary course, which correlates with protection against clinical disease.
Recombinant vaccines tend to produce rapid antibody responses and strong safety records, while inactivated vaccines have a long history of predictable performance and minimal reactogenicity.
Primary vaccination usually requires a two-dose course separated by a few weeks, followed by periodic boosters; veterinarians tailor schedules by age, pregnancy status, and prior vaccination history.
Post-licence surveillance and pharmacovigilance in Europe and North America report low rates of serious adverse events, with most reactions being mild and transient injection-site responses.
Vector and seasonality studies for Culex mosquitoes support targeting vaccination ahead of high-risk months; combined with local risk assessment this helps optimise timing of primary courses and boosters.
Regulatory reviews from national authorities, including the UK Veterinary Medicines Directorate, and peer-reviewed immunogenicity studies form the basis for product-specific recommendations.
Frequently Asked Questions
Which West Nile vaccine should I choose for my horse?
Choose Proteq West Nile for at-risk horses needing a faster-onset immune response, since it uses recombinant canarypox-vectored technology (strain vCP2017) to stimulate cellular and humoral responses; it has a 4.5 average rating. Equilis West Nile, an inactivated vaccine, is the established alternative with a 4.3 average rating.
What is the key technology difference between Equilis West Nile and Proteq West Nile?
Equilis West Nile (MSD Animal Health) is an inactivated vaccine, while Proteq West Nile (Boehringer Ingelheim) is a live recombinant canarypox-vectored vaccine expressing West Nile virus preM/E proteins. Both are given as a two-dose primary course with annual boosters.
Is Proteq West Nile worth the extra cost for mosquito season?
Proteq West Nile (around £130-220) typically sits at a premium versus inactivated options like Equilis West Nile (around £120-200). The recombinant platform can deliver a faster-onset response, which may justify the cost for higher-risk horses; both require veterinary administration. Proteq has a 4.5 average rating, Equilis 4.3.
Do Equilis West Nile and Proteq West Nile suit the same horses?
Both are administered by a veterinarian as two-dose primary courses with annual boosters aligned to UK guidance, and both are licensed for use in horses from around five to six months old. Proteq West Nile is favoured for a rapid antibody response, while Equilis West Nile is valued for its well-tolerated, established inactivated profile.
Conclusion
In the UK context, choosing the right West Nile vaccine is about matching product characteristics to your yard, horse population, and seasonal risk. The two highlighted products on this page, Equilis West Nile and Proteq West Nile, are widely used options with established safety and efficacy records; Equilis West Nile is generally favoured by many UK veterinarians for its balance of field performance and handling, while Proteq West Nile remains a strong alternative where its specific formulation or schedule better suits a yard's needs. I hope you found the comparison useful — if you want to refine results by horse age, pregnancy status, or booster interval, use the site search to expand or narrow your options.