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POM-V Prescription Required

Equilis Prequenza, Suspension for Injection, for Horses

Active ingredient: Equine influenza virus

Form

Injection

Species

Horses

Manufacturer

MSD Animal Health UK Limited

VMD MA No.

01708/5032

What it's used for

Active immunisation of horses from 6 months of age against equine influenza to reduce clinical signs and virus excretion after infection. Onset of immunity...

Full indications, dosage and side effects ↓
View official SPC (PDF)

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Paying less for Equine influenza virus

  1. 1

    Ask your vet for a written prescription

    They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.

  2. 2

    Fill it at a registered online retailer

    The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Equilis Prequenza, Suspension for Injection, for Horses — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.

Active immunisation of horses from 6 months of age against equine influenza to
reduce clinical signs and virus excretion after infection.
Onset of immunity: 2 weeks after the primary vaccination course
Duration of immunity: 5 months after the primary vaccination course
1 year after the first revaccination
None.

Revised: November 2023
AN: 03456/2022
Horses:
Rare
(1 to 10 animals / 10,000 animals
treated):
Injection site swelling
, Injection site
pain
.
Very rare
(<1 animal / 10,000 animals treated,
including isolated reports):
Fever
, Lethargy
, Inappetence
,
Hypersensitivity reaction
.
A diffuse hard or soft swelling (max. diameter 5 cm), regressing within 2 days. A local reaction
exceeding 5 cm and possibly persisting longer than 2 days may occur in very rare cases.
Pain at the injection site may result in temporary functional discomfort (stiffness).
Fever, sometimes accompanied by lethargy and inappetence, may occur for 1 day, and up to
3 days in exceptional circumstances.
Including anaphylaxis (sometimes fatal). If such a reaction occurs, appropriate treatment
should be administered without delay.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or the national competent authority via the
national reporting system. See also the package leaflet for respective contact details.
Foals should not be vaccinated before the age of 6 months, especially when born to
mares that were revaccinated in the last two months of gestation, because of
possible interference by maternally derived antibodies.

Special precautions for use in animals:
Vaccinate healthy animals only.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
In case of accidental self-injection, seek medical advice immediately and show the
package leaflet or the label to the physician.
Special precautions for the protection of the environment:
Not applicable.
Other precautions:
Not applicable
No information is available on the safety and efficacy of this vaccine when used with
any other veterinary medicinal product.
A decision to use this vaccine before or after any other veterinary medicinal product
therefore needs to be made on a case by case basis.
Store in a refrigerator (2 C – 8 C).
Do not freeze.
Protect from light.
Zero days.
5. IMMUNOLOGICAL PROPERTIES
Pharmacotherapeutic group:
ATCvet code: QI05AA01.
To stimulate active immunity against Equine influenza in horses.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.

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