BHA Vaccination Calculator, Check Race Eligibility
Checking whether your horse's vaccination record is race-ready, or worried a booster might be overdue? Use this calculator to instantly verify compliance under current BHA rules.
This is an educational tool. Always confirm final compliance with your vet or the BHA.
Results & Analysis
How the BHA Vaccination Calculator Works
This calculator relies on the latest British Horseracing Authority (BHA) rules to validate equine influenza passports. It calculates the exact days between dates to ensure no booster is administered too early or late.
BHA Vaccination Schedule Explained
V1, V2 and V3 Vaccination Dates
For primary courses started on or after 1 January 2022, the intervals are strictly defined to provide optimal immunity:
| Vaccine | Current Rule (From 1 Jan 2022) | Old Rule (Before 1 Jan 2022) |
|---|---|---|
| V1 | Initial Dose (Day 0) | Initial Dose (Day 0) |
| V2 | 21 - 60 days after V1 | 21 - 92 days after V1 |
| V3 | 120 - 180 days after V2 | 150 - 215 days after V2 |
Booster Vaccination Rules
Equine influenza boosters must be administered at intervals of no more than 365 days. No horse can race without a compliant booster record.
Race Date and Vaccination Timing
Ensure your race date complies with the 'seven clear days' principle. No horse may run in a race if it has been vaccinated within 7 days of the scheduled race day.
BHA Vaccination Timeline
V1
The starting point.
V2 (21 - 60 days)
Given after the first dose to boost immediate immunity.
V3 (120 - 180 days after V2)
Secures longer-term primary immunity.
Annual Boosters
No more than 365 days apart continuously.
Frequently Asked Questions
It is an educational tool designed to help horse owners, trainers, and vets check whether a horse’s equine influenza vaccination record complies with the British Horseracing Authority (BHA) rules. It calculates interval days to ensure boosters are administered within the correct timeframe.
Enter your horse's V1, V2, V3, and recent booster dates from their passport into the calculator. A compliant record will confirm that all vaccination intervals fall within the strict BHA limits (e.g., 21-60 days for V2 post-2022) and that no booster is overdue.
Under BHA rules, intervals are strictly monitored. If an annual booster exceeds 365 days, or any primary course interval is missed by even a single day, the vaccination is invalid. The horse must restart its entire primary vaccination course (V1, V2, and V3) before entering a racecourse.
No. The BHA enforces a strict 'seven clear days' principle. A horse cannot run in a race if it has received an equine influenza vaccination within seven days of the scheduled race day, to uphold welfare and prevent vaccine reaction masking.
You will need the dates written inside your horse's passport for its most recent primary course (V1, V2, and V3) and its most recent booster vaccination.
No. While this tool provides highly accurate interval calculations based on BHA guidelines, it remains an educational guideline. Final authority and compliance clearance always rests with the BHA, Weatherbys, and your veterinary professional.
Yes. Completing the primary sequence (V1, V2, V3) again is the only remedy once an interval limit is actively exceeded. The horse cannot race until at least V1 and V2 have been administered compliantly.
V1, V2, and V3 form the 'primary course' to establish base immunity against equine influenza. V1 is the first dose, V2 is given 21-60 days later, and V3 is given 120-180 days after V2. Boosters are subsequent top-up vaccinations required at intervals of no more than 365 days.