Vaccinations - essential protection
There are several highly infectious and potentially fatal diseases that can affect your rabbit. Fortunately, vaccines have been produced that will protect your rabbit against two of these - myxomatosis and viral rabbit haemorrhagic disease (strains 1 and 2). To ensure that your rabbit is fully protected it is essential that it receives regular booster injections.
How do vaccines work?
Vaccines are given by injection under or into the skin in rabbits. They all work by training the white blood cells in your rabbit's body how to recognise and attack the viruses or bacteria contained in the vaccine. This should prevent infection with that particular microorganism if your rabbit is in contact with it again.
Current vaccines fall into two main categories: 'live vaccines' which contain a strain of the bug which has been altered so that it cannot cause disease but does stimulate immunity, and 'dead vaccines' in which the bug has been killed by heat or chemicals. Each type has their pros and cons - live vaccines generally give better and longer-lasting protection but they can sometimes cause more side-effects. Live vaccines are not recommended for certain groups of rabbits, such as pregnant females. The combined Myxo-RHD vaccination which offers protection against Myxomatosis and RHDV-1 is a live vaccine. The RHD-2 strain vaccines are all inactivated 'dead vaccines'. The new triple Myxo-RHD PLUS vaccination is a live vaccination that protects against myxomatosis and rabbit haemorrhagic disease, both classic (RHDV-1) and variant strains (RHDV-2).
What is myxomatosis?
Myxomatosis is a disease caused by a virus. It only affects rabbits, but both wild rabbits and pet rabbits are susceptible. The virus causes severe swelling of the lips, eyelids and genitals. Wild rabbits suffering from this condition usually fall victim to predators, eg foxes, or are hit by cars. Pet rabbits can sometimes recover from the condition with very intensive nursing, but most are euthanased.
The virus causing myxomatosis is transmitted between infected and healthy rabbits by insects, particularly rabbit fleas, but also by flies. Cats often become infected by rabbit fleas and will bring these into your garden or inside your house. Therefore, even if your rabbit lives indoors or if you live in a city centre, far from places where wild rabbits live, your pet rabbit could still be at risk.
What is viral haemorrhagic disease?
Viral haemorrhagic disease (VHD or RVD) is a horrible viral condition that only affects rabbits. It is caused by a highly contagious virus which is transmitted from rabbit to rabbit, or on contaminated equipment, clothing and feed. Insects, rodents and birds may also be able to carry the virus and infect isolated rabbits (such as pet rabbits).
RHD-1 is nearly always fatal; it causes massive bleeding (haemorrhage) from the internal organs and the animals die as a result of the overwhelming blood loss.
RHD-2 is fatal in around 7-20% of cases, but as it kills slower it has more of a chance to spread. The virus often has very non-specific clinical signs which may just be that the rabbit seems slightly off-colour or may show no signs at all. There is no way of diagnosing or differentiating what strain of RHD a rabbit is affected with unless it is confirmed on post-mortem.
When should my rabbit be vaccinated?
Rabbits can be vaccinated against myxomatosis, RHD-1 and RHD-2. Most vaccinations provide immunity for one year. Myxomatosis is generally a seasonal disease, although it can occur all year round, and the numbers of cases peak significantly in the late summer/early autumn.
A triple combined vaccine against myxomatosis, RHD-1 and RHD-2 is now available in the UK (Nobivac Myxo-RHD PLUS). This is an annual vaccination and can be given from 5 weeks of age. Rabbits that have been previously vaccinated with another vaccine will have to follow a switching process that your vet can discuss with you. This might require an additional vaccination with an RHD-2 vaccination the first year in some cases.
Nobivac Myxo-RHD is an annual combined booster that provides adequate immunity for one year for both myxomatosis and RHD-1. This vaccination is now being substituted by the triple vaccine and will shortly no longer be available.
Vaccination for RHD-2 depends on what vaccine your vet has access to:
- Filavac VHD K C + V: the most readily available vaccine; can be given from 10 weeks of age and an annual booster is sufficient except in high-risk areas or high-risk rabbits, eg show rabbits, rescue centres, etc, where a 6 monthly booster is recommended.
- Cunivak RHD: can be given from 4 weeks of age and a second initial vaccination is needed 3 weeks after; an annual booster is sufficient thereafter. Not currently available in the UK.
- Cunipravac RHD: available only in multidose vials that have to be used within 8 hours of opening. For this reason, this vaccine is not normally used by vets for pet rabbits, although may be used for breeders who have multiple rabbits to vaccinate at the same time. The vaccine can be given from 4 weeks of age and requires a second initial vaccination 6 weeks after followed by 6 monthly boosters. The vaccine is oil based which can cause skin reactions.
With all RHD-2 vaccinations, a 2 week gap between them and the Nobivac Myxo-RHD vaccine must be left since none of the vaccines have had trials to determine how they react with the Nobivac Myxo-RHD vaccine.
The combined Myxo-RHD vaccination and the triple Myxo-RHD PLUS vaccination are not recommended in pregnant does or bucks intended to be used for breeding, since safety in these groups has not been trialled sufficiently.
How is the vaccination given?
The vaccinations are given by injection usually into the scruff at the back of the neck.
The old myxomatosis vaccination needed a small amount of the vaccine to be given intradermally (into the rabbit's skin), but the triple Myxo-RHD PLUS, the combined Myxo-RHD vaccine and all the RHD-2 vaccines do not require this, and the entire volume is administered subcutaneously (under the skin) into the scruff of the neck.
Why is it necessary to have repeat vaccinations?
The protection given by most vaccines wears off in time. Booster injections ensure that your rabbit has continuing immunity against the diseases.
Do vaccines fail to work sometimes?
Occasionally a rabbit may not be fully protected against a condition, even after vaccination. This may be because the rabbit was already ill or was stressed when it was vaccinated, and its immune system wasn't working properly. Your vet will examine your rabbit before vaccination and if any signs of illness are detected will delay vaccination until your rabbit is well again.
If using the new triple vaccination Myxo-RHD PLUS, rabbits vaccinated with other myxomatosis vaccines or those that have been exposed to the myxomatosis virus, may not develop a proper immune response to RHD following vaccination. Your vet will discuss the switching process and in the first year this might involve an extra RHD-2 vaccination in some cases.
There have been a small number of cases reported of rabbits vaccinated with the old myxomatosis vaccination contracting the disease. These rabbits exhibited symptoms of a very mild form of the disease and all recovered. In these cases, the vaccine may have protected them from the severe form of the disease.
Can vaccinations be dangerous?
Sometimes your rabbit may seem 'off colour' for a day or two after its vaccination and the injection site may also become tender and swollen. If these effects do not wear off it is worth taking your rabbit back to see your vet. If you are concerned about any symptoms in your rabbit do not hesitate to contact your vet for reassurance or advice.