Virbagen Omega for Dogs & Cats

Virbagen Omega for Dogs & Cats
10mu Vial (Pack of 2)

  • 10mu Vial (Pack of 2) £212.50
  • 10mu Vial (Pack of 5) £458.50

Selection of 2 products from

£212.50 to £458.50


Virbagen Omega is a unique product containing a form of feline interferon. This is given by injection to treat certain viral infections and immune problems in both cats and dogs. The mechanism of action is not fully understood, but it has been found in clinical trials to be of benefit in such things as Parvo virus infection in dogs and Feline Leukamia virus infection. The precise treatment schedule has to be followed exactly to get the best results. For further information, see the datasheet below.

Name of the Veterinary Medicinal Product

Virbagen Omega 10 MU for cats and dogs.

Qualitative and quantitative composition

Vial containing lyophylisate.

Active substance 10 MU presentation:

Recombinant omega interferon of feline origin 10 MU*/vial.

*MU: Million units.


Sodium chloride, D-sorbitol, gelatin.

Vial containing solvent: isotonic sodium chloride solution 1ml.

Pharmaceutical form

Powder and solvent for suspension for injection.

Immunological properties

Pharmaceutical group: ATC vet-Code: QL03 AB.

The exact mechanism of action of omega interferon is not perfectly known, but may involve the enhancement of the non-specific defence of the body, in particular in the dog against canine parvovirosis. Interferon does not act directly and specifically against the pathogenic virus, but exerts its effect by inhibition of the internal synthesis mechanisms of the infected cells. Omega interferon of feline origin, produced by genetic engineering, is a type 1 interferon related to alpha interferon. After injection it is quickly bound to specific receptors of a large variety of cells. It is mainly in cells infected by the virus that the mechanism of replication is stopped both by destruction of mRNA and by inactivation of translation proteins (2’ 5’ oligo-adenylate synthetase activation).

Clinical particulars

Target species: Dogs and Cats

Indications, contra-indications, undesirable effects

For the reduction in mortality and clinical signs of parvovirosis (enteric form) in dogs from one month of age.

Vaccination during and after Virbagen Omega treatment is contra-indicated until the dog appears to have recovered.

Cats :

Treatment of cats infected with FeLV and/or FIV, in non-terminal clinical stages, from the age of 9

weeks. In a field study conducted, it was observed that there was :

- a reduction of clinical signs during the symptomatic phase (4 months)

- a reduction of mortality :

• in anaemic cats, mortality rate of about 60% at 4, 6, 9 and 12 months was reduced by approximately 30% following treatment with interferon.

• in non-anaemic cats, mortality rate of 50 % in cats infected by FeLV was reduced by 20% following treatment with interferon. In cats infected by FIV, mortality was low (5%) and was not influenced by the treatment.

In some cases during treatment the following transient clinical signs may be onserved:

Hyperthermia (3-6 hours after injection)


Soft faeces to mild diarrhoea, in cats only.

In addition, a slight decrease in white blood cells, platelets and red blood cells, and rise in the concentration of alanine aminotransferase may be observed. These parameters return to normal in the week following the last injection.

Transient fatigue during the treatment, in cats only.

Special precautions for use

Dogs and cats: it was shown that strict compliance with the recommended posology is compulsory to achieve clinical benefit.

Cats: In case of repeated treatments of chronic diseases associated with hepatic, cardiac and renal failure, the corresponding disease has to be monitored prior to administration of VIRBAGEN OMEGA. Fluid therapy and other supplementary supportive treatment are necessary to improve prognosis.

The product should be used with the accompanying solvent only.

Pregnancy and lactation

The safety of Virbagen Omega has not been established during pregnancy and lactation.

Interactions with other medicaments and other forms of interaction

The use of supplementary supportive treatments improves prognosis. No interaction has been observed during the treatment with VIRBAGEN OMEGA together with antibiotics, solution for rehydration, vitamins and non steroidal anti-inflammatory agents. However, as specific information on possible interactions of interferon with other products are missing, supplementary supportive treatments should be used cautiously and after a thorough risk/benefit analysis.

No information is available on the safety and efficacy from the concurrent use of this product with any other vaccine. For dogs, it is recommended that no vaccines should be administered until the animal appears to have recovered. Cat vaccination during and after VIRBAGEN OMEGA treatment is contraindicated as both FeLV and FIV infections are known to be immunosuppressive.

Dosage and method of administration

The freeze-dried fraction must be reconstituted with 1 ml of the specific diluent to obtain a solution containing 10 MU of recombinant interferon.


The reconstituted product should be injected intravenously once daily for 3 consecutive days. The dose is 2.5 MU/kg bodyweight.


The reconstituted product should be injected subcutaneously once daily for 5 consecutive days. The dose is 1 MU/kg bodyweight. Three separate 5-day treatments must be performed at day 0, day 14 and day 60.


After a tenfold overdose in both dog and cat the following clinical signs have been observed :

• mild lethargy and drowsiness

• slight increase of body temperature.

• slight increase of respiratory rate

• slight sinus tachycardia.

These clinical signs disappear within 7 days without any particular treatment.

Special warnings

No information on the induction of long-term side effects is available in dog and cat, especially for autoimmune disorders. Such side effects have been described after multiple and long-term administration of type I interferon in man. The possibility of occurrence of autoimmune disorders in treated animals cannot therefore be ruled out and has to be balanced with the risk associated with FeLV/FIV infections.

Efficacy of the product on cats with a tumorous form of the infection by FeLV, or cats infected by FeLV or coinfected by FIV in terminal stages was not tested.

In the case of intravenous administration in cats, increased adverse reactions may be seen, e.g. hyperthermia, soft faeces, anorexia, decreased drinking or collapse.

Withdrawal period

not applicable.

Special precautions to be taken by the person administering the medicinal product to animals:

In case of accidental self-injection, seek medical advice immediately and show the package insert or the label to the physician.

Pharmaceutical particulars


do not mix with any other vaccine/immunological product, except the solvent supplied for use with the product.

Shelf life

2 years

Special precautions for storage

Store and transport at 4° C ± 2° C. Do not freeze. Store in the original carton.

Nature and contents of container

Presentation of 10 MU per vial:

Box containing 5 vials (glass with stopper) of powder fraction and 5 vials (glass with stopper) with 1 ml of solvent.

Box containing 2 vials (glass with stopper) of powder fraction and 2 vials (glass with stopper) with 1 ml of solvent.

Special precautions for the disposal of unused medicinal product or waste material

any unused product or waste materials should be disposed of according to local requirements.

Other information


Name and address of the marketing authorisation holder

Virbac SA

L.I.D. 1ere Avenue – 2065m


Marketing authorisation numbers

VIRBAGEN OMEGA (5 x 10MU) EU/2/01/030/002

VIRBAGEN OMEGA (2 x 10MU) EU/2/01/030/004

Need help or advice? Contact us:

  • Landline: 01582 842096
  • Mon - Fri: 8:30am - 5:00pm
  • Sat: 9:00am - 1:00pm
  • Email: [email protected]

All prices include VAT where applicable.

Delivery Information

How quickly do you deliver?

Under almost all products on our website is an Estimated dispatch time, check this for a delivery prediction specific to the item you are looking to purchase. These badges are updated live based on the stock levels we have and also those of our suppliers - so are usually very accurate, but cannot be guaranteed. In more general terms, we aim to dispatch all orders within 1 working day of receiving payment (and a prescription if required). If we cannot do so within 3 working days we will contact you by email.

What do you charge for delivery?

For UK delivery, we charge the following:

Order Total Weight Delivery
£0-£28.99 Under 2kg £2.99
2kg+ £4.99
£29-£38.99 Under 2kg Free
2kg+ £4.99
£39+ Under 2kg Free
2kg+ Free

Prices quoted are for delivery to all parts of mainland UK except certain Scottish postcodes (where the price is higher for items sent by courier. Delivery of food abroad (including Channel Islands, N. Ireland and other islands around the UK) is charged at a higher price and free delivery is not available. Temperature controlled products, such as Insulin, are also not always subject to the standard and/or free delivery options.

For full information on our delivery charges, including prices on heavy deliveries to Scotland and abroad, see our delivery information page.

We can deliver most items to all around the world, but prices do vary. The majority of light weight orders (less than 1.5kg) can be delivered for a flat rate of £10. For an accurate estimate of the delivery charge, please put the items you require in your basket and use the "Estimate Delivery" system on the shopping basket page (you only need to enter your country and postal/zip code) for a quick quote. For deliveries to the USA you may need to go to the checkout page and enter your full address to get a quote (as some services need your state in order to quote too). For more information on international deliveries, please see our delivery information page.

Delivery of aerosols

Due to air freight restrictions aerosols cannot ever be sent abroad by Royal Mail. We appreciate your understanding.

Delivery of temperature controlled items

Some products, such as insulin and frozen food, need to be delivered in insulated packaging to prevent them from getting too warm (or too cold) during transit from us to you. Purchasing any of these items in your order will result in a £1.99 charge being added to the total to cover the high cost of the insulated packaging materials. You only pay the £1.99 once per order, regardless of how many temperature controlled items you purchase in that order.

How do I cancel or return an order?

Please call us as soon as possible if you need to amend or cancel an order on 01582 842096. If your order has been processed for dispatch we will be unable to cancel or amend the order. You will however be able to return your product for a full refund*.

To return an item, you must contact us by phone or email to arrange this BEFORE posting any product back to us. We will explain the process at this stage for you.

*For full details on returns, see our terms and conditions page.

Reviews (4)

Q & A

Below are some recent questions we've received regarding Virbagen Omega for Dogs & Cats, including answers from our team.

1 August 2017 10:20pm

Delivery to other countries

Cenk Karaduman

  • VioVet Customer Since: August 2017
  • From: İstanbul, Turkey

Are you delivering this product to Germany or Netherlands? Do you ensure the cold chain during delivery of this product?

  • Veterinary Advisor

Yes we can send this product to Germany and the Netherlands. At checkout there will only be an option for Fedex International Priority delivery. This means the product will leave our warehouse by 3pm and delivered within 24 hours with icepacks included to keep the product cool.

11 February 2016 1:01pm

Cat with flu


  • VioVet Customer Since: October 2007
  • From: , United Kingdom

My 8 month old maine coon has flu symptoms. He has been treated with interferon at 0.1ml on day 1,4&6 he is 5kgs. He presented with a bacterial infection and at first this responded well to baytril injection he quickly deteriorated when he went on to the tablet form. He has had his antibiotics changed and now the bacterial infection is slowly improving. Is it worth trying interferon again with him after bacterial infection has cleared up and at what dose would we need to use.

  • Non-Executive Director

This is difficult to answer by email because there are lots of factors to take into account. Your own vet is in a better position to assess this. However I would say that this interferon product does not always seem to help much in this sort of situation. Microbial culture and sensitivity testing to help with antibiotic choice is an important part of treating the bacterial component and general nursing measures to help with food and fluid intake are also important. I hope things go well.

28 September 2015 5:50am

My cat has leukemia an he is two going on three an he is throwing up an what can I do


What should I do

  • Non-Executive Director

This has to be a question for your own vet, who can properly assess your cat. The Virbagen product might well help, but I am not in a position to be able to advise you. I hope he does well though.

6 August 2015 8:18am

Cost of treatment with this

Dee j

Hi,trying to work out if I can afford to give my cat with wet FIP a chance with this drug, could you give me any idea how much treating a 2kg cat might cost,per treatment or week or month,would be very grateful of any estimate,thank you.

  • Non-Executive Director

One 10mu vial contains enough product to treat a 10kg animal. Theoretically this could be 5 treatments for a 2kg cat, but that would mean mixing up the vial with the diluent and then storing the remainder for up to 4 days. Ideally fresh product is mixed up every day, but many vets will use part of a vial and get part or all of a treatment course from 1 vial. The standard treatment course for a cat is one injection per day for 5 days, then a 5 day course repeated again after about 2 weeks, then again at 8 weeks. This means that the cheapest full course for a 2 kg cat would take 3 vials. You have to buy them in pairs and 4 vials would cost about £320. If your vet feels that a fresh vial is needed per day, then that would cost 5 times as much, so you need to check this with your vet.

26 July 2015 11:01pm

Feline Leukemia

Luisa Angel

Please I would like to know if the virbac omega will improve the life of a one year old cat that has leukemia? Thank you

  • Non-Executive Director

This product is often used for cats like this and the results are variable but there are often signs of improvement with a better quality of life and statistically an increased life expectancy. It is certainly worth trying.

27 May 2015 2:57pm

Interferon and low immune system.


Hi there.
My cat has a very low immune system due to his bad health history. In past it started with Calici virus and now it's chronic Pasteurella spp and recent discovery of toxoplasmosis.
We are considering not just treatment with antibiotic but also Virbac interferon treatment.
We were just wondering is there any information about interferon use in those illnesses?
Many thanks

  • Non-Executive Director

We have no special information of our own on this sort of thing. Some people have used the product with variable success for all sorts of immune-related problems and infections. You can search online for reports of these and make your own judgments. We are only able to advise on licensed use, which is in the data sheet. Your own vet is best able to assess these other things.

25 March 2015 11:18pm

Side effects of Interferon

Paula Sibley

Our cat is on Interferon for Calicivirus and he tears at his fur nearly all the time. Also tonight after a bout of this his gums bled quite a lot. Are these side effects of Interferon?

  • Non-Executive Director

These are not usual side effects with this treatment. Cats which remove their own fur are not unusual and this behaviour is normally associated with allergies affecting the skin (especially flea bites) or sometimes stressed/nervous behaviour (a habit a bit like people biting their nails). I would see your vet about this, or contact a cat behaviourist.

9 March 2015 11:27pm

Is it can help to cat that was diagnosed with dry form FIP?

Alona Zakuta

Our kitty is 4 years old was diagnosed with dry form FIP one year ago,in USA,since she is getting POlyprenyl immunostimulant,just want to know if it's can be more helpful to give her as well Feline omega interferon with in,now we living in Israel
Thank u for your attention and time!

  • Non-Executive Director

This product has abeen shown to have some beneficial effects in some cats with FIP, but the results tend to be variable and not dramatically better than in untreated patients.I do not think it will cause any harm and so if you an afford it, it might well be worth trying.

7 March 2015 11:07am

Interferon and calici


My kitten's test for calici has come back with a low grade infection. I have been told that a course of interferon can clear that and make him non infectious to other cats. Help please!

  • Non-Executive Director

This interferon product does help cats to fight viral infections, but it is not as clear cut as you suggest. It seems to be a safe enough treatment and he is likely to benefit from a course of treatment, but the extent to which it will help seems to vary from cat to cat. If the infection is low-grade, there might not be any requirement to treat him at all. If however his symptoms warrant it, then if you can afford the treatment it is sensible to provide it.

28 November 2014 12:07am

Wet FIP n virbagen for cat


I have heard virbagenvirbagen and PI are helpful or rather have been somewhat successful in helping cats with FIP the dry version. Will this help my 7 month old kitten with wet FIP. She still likes to eat n lay by my side yet she is anorexic lethargic n the vet drew yellow liquid out of her belly. ....would this ease her discomfort her symptoms? I'm desperate here...

  • Non-Executive Director

The effusive form of FIP does sometimes show a response to this drug, particularly if given early on in the development of the condition. Results are variable but occasionally are very good, so it would certainly be worth discussing this with your vet. We can supply it on receipt of a written prescription from your vet.