POM-V Prescription Required

Enzovax

Active ingredient: Chlamydophila abortus

Form

Injection

Species

Sheep

Manufacturer

Intervet International B.V.

VMD MA No.

06376/4103

What it's used for

Duration of immunity: Challenge studies have demonstrated that protection against enzootic abortion and excretion of Chlamydia abortus post-challenge is un...

Full indications, dosage and side effects ↓

View official SPC (PDF)

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Paying less for Chlamydophila abortus

1

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2

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Prescription required

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Clinical information

Enzovax — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 27 Mar 2026.

Duration of immunity: Challenge studies have demonstrated that protection against
enzootic abortion and excretion of Chlamydia abortus post-challenge is undiminished
for at least three years post vaccination with the veterinary medicinal product. Field
studies in endemically infected flocks maintaining a policy of vaccinating incoming
ewes with the vaccine indicate that enzootic abortion levels remain very low in ewes
vaccinated 4 years previously.

Dose: 2 ml.
Reconstitution:
The vaccine is reconstituted with the solvent (Unisolve) immediately prior to use,
allowing 2 ml of solvent per dose.
If using the vented transfer device push one end of the device through the centre of
the vaccine vial using a firm, twisting action. Similarly, push the Unisolve vial onto the
opposite end of the device taking care to ensure the spike penetrates the centre of
the vial bung. Carefully allow solvent to flow into the vaccine vial without completely
filling it. Ensure the vaccine plug is fully dissolved and then invert until all the vaccine
suspension drains into the solvent vial. Remove the empty vaccine vial and the
transfer spike from the solvent vial and place them into an appropriate disinfectant
solution.
Alternatively, remove approximately 5 ml of Unisolve from the vial with a syringe and
needle, inject into the vaccine vial and swirl gently until the vaccine plug is fully
dissolved. Remove the vaccine suspension from the vial, re-inject into the solvent vial
and mix gently. Great care should be taken not to generate an aerosol. After
reconstitution the vaccine should be kept cool and used as soon as possible (within 2
hours).
Visual appearance after reconstitution: Off-white suspension.
Administration
Ewe lambs, where it is intended to breed from them, may be vaccinated from 5
months of age. Shearlings and older ewes should be vaccinated during the 4 month
period prior to mating.
Vaccination must take place at least 4 weeks before mating.
Injection equipment
To minimise the risk of self-injection the vaccine should be administered using a
disposable automatic syringe fitted with a guarded needle system according to the
manufacturer's instructions. It is vital that a vented draw off tube is used with this
equipment.
Regular checks should be made to ensure the syringes are properly calibrated.
Carefully attach the vial of reconstituted vaccine to the injection equipment and avoid
creating aerosols during the priming process. It may be advisable to wear a visor
while carrying out this operation.
Revaccination policy
Challenge studies have demonstrated that protection against enzootic abortion and
excretion of Chlamydia abortus
years post vaccination with the veterinary medicinal product.

Amended pages: October 2025
Revaccination is recommended every 3-4 years depending on farm management
practices and conditions.
Field studies in endemically infected flocks maintaining a policy of vaccinating
incoming ewes with the vaccine indicate that enzootic abortion levels remain very low
in ewes vaccinated 4 years previously.

Do not vaccinate pregnant animals.
Do not vaccinate animals less than 4 weeks before mating.
Do not vaccinate animals which are being treated with antibiotics, particularly
tetracyclines.

Sheep (ewes):
Very common
(>1 animal / 10 animals
treated):
Elevated temperature
.Very rare
(<1 animal / 10 000 animals
treated, including isolated
reports):
Abortion
;
Hypersensitivity reaction (e.g. Tachypnoea, pale
mucous membranes, collapse)
.
Transient and

average up to 1.5 °C for a maximum of 3 days after vaccination.
May occur where the vaccine strain can be identified.
Such reactions may evolve to a more severe condition (anaphylaxis), which may be
life-threatening.
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 its local representative or the national
competent authority via the national reporting system. See the package leaflet for
respective contact details.

Vaccinate healthy animals only.
Chlamydia abortus is only one of the causes of abortion in sheep. If the abortion rate
remains unchanged in flocks which have been vaccinated with the vaccine it is
recommended that veterinary advice is sought.
The epidemiology of abortion due to Chlamydia abortus in ewes involves a long
incubation period. Ewes that abort in any lambing season have usually been infected
at the previous lambing. Field trial data indicate that vaccinating incubating ewes will
reduce the incidence of abortion, but a proportion can still go on to abort.
Care should be taken in handling such abortions as susceptible humans may be at
risk of infection.
A good immune response is reliant on the reaction of an immunogenic agent and a
fully competent immune system. Immunogenicity of the vaccine antigen will be
reduced by poor storage or inappropriate administration. Immunocompetence of the
animal may be compromised by a variety of factors including poor health, nutritional
status, genetic factors, concurrent drug therapy and stress.

Special precautions for safe use in the target species:
None.

Amended pages: October 2025
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
Care should be taken to avoid accidental self-injection. In case of accidental self-
injection, seek medical advice immediately and show the package leaflet or the label
to the physician. The physician should be informed that self-injection with a living
chlamydia vaccine has occurred.Tetracycline therapy is the current recognised
treatment for infection with in humans.Personal protective
equipment consisting of gloves should be worn when handling the veterinary
medicinal product.
The veterinary medicinal product should not be handled by pregnant women or
women of childbearing age as the vaccine may cause abortion.
Immunocompromised persons are advised to avoid contact with the vaccine.
Special precautions for the protection of the environment:
Not applicable.

Safety and efficacy data are available which demonstrate that this vaccine can be
administered on the same day but not mixed with Toxovax. The vaccines should be
given at different sites.

Amended pages: October 2025
No information is available on the safety and efficacy of this vaccine when used with
any other veterinary medicinal product except the product mentioned above. 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.

Lyophilisate:
Store and transport refrigerated (2 °C – 8 °C).
Do not freeze.

Amended pages: October 2025
Protect from light.
Solvent:
Store below 25 °C (if stored separately).
Do not freeze.

Meat and offal: 7 days.

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.