Why are there several different RHD vaccines for rabbits? 

What is RHD? 

Rabbit haemorrhagic disease (RHD, sometimes referred to as viral haemorrhagic disease/VHD or rabbit viral haemorrhagic disease/RVHD) is an infection that can have devastating consequences for rabbits. RHD is a viral infection spread by direct contact with infected animals or through contaminated environments, food, clothing, and bedding. It can also be spread by insects, birds, and rodents. RHD is a type of calicivirus and is very hardy. This means that it can survive in the environment for extended periods and withstand conditions such as freezing temperatures.  

The other important thing to note is that there are a couple of strains of this virus, referred to as RHD1 and RHD2. Both strains can be deadly, and once your rabbit contracts them, there is little that can be done other than providing supportive care. Sudden death is very common.  

RHD1 

RHD1 is usually fatal. The virus attacks internal organs, especially the liver, causing internal bleeding. Almost 100% of infected rabbits will die within less than 48 hours. Very young rabbits, under the age of 6 weeks, are often immune to its effects, however. 

RHD2 

RHD2 has been more recently discovered and tends to be less rapid than RHD1, with symptoms sometimes appearing gradually. These can be non-specific, such as a reduced appetite, lethargy, or being ‘off colour’. Sudden death can also occur. 

The mortality rate of RHD2 is variable but typically lower than that of RHD1. Younger rabbits (under the age of 6 weeks) seem to have no immunity to RHD2 though, unlike with RHD1.  

Recently however, more virulent strains of RHD2 have been reported, leading to a change in vaccination protocol by some vets, with vaccines that also protect against the newer strains of the virus. The highly virulent versions of RHD2 have a mortality rate thought to be nearer 100%. This is likely to be due to high mutation rates and genetic recombination, meaning the virus is constantly evolving. It is becoming better adapted at avoiding its host’s immune responses.  

What are the symptoms of RHD? 

Symptoms of RHD can be variable depending on your rabbit’s age and the virus strain involved. Some rabbits may suffer from hyperacute infection and die suddenly, whereas a smaller proportion may experience a more chronic version, where symptoms have more time to appear. We are not able to tell the difference between infection with RHD1 and RHD2 until postmortem. 

Common symptoms include – 

• Non-specific signs like lethargy, reduced appetite, and weight loss 

• Seizures 

• Bleeding from the nose 

• Jaundice (yellowing of the skin and mucous membranes) due to liver failure  

• Sudden death, often with blood coming out of the nose, mouth, and sometimes anus 

RHD2 is more likely to cause non-specific symptoms, which can sometimes be mistaken for other issues or disease processes. 

Is there any available treatment for RHD? 

Sadly, there is no cure for either RHD1 or RHD2. Any treatment given will be symptomatic, and sometimes euthanasia is recommended to prevent further suffering. If your rabbit has contracted RHD1, this will almost certainly be fatal. Some rabbits may survive RHD2, but numbers are unclear. The rise in a more virulent version of RHD2 may change this. 

The best way to protect your rabbit is through vaccination. 

Vaccinating against RHD 

Vaccination is recommended for all pet rabbits, including indoor ‘house’ rabbits. Given that the disease can be spread by vectors like flies and other insects, as well as on bedding and clothing, you should be proactive and protect your rabbit. 

The vaccination protocols for RHD have evolved over time. Currently, vets recommend a combined vaccine which can be given from 5 weeks of age. This vaccination is administered once a year and gives protection against – 

• RHD1 

• RHD2 

• Myxomatosis 

Previously these components needed to be administered separately, which some pet owners may still remember. The combined vaccine has superseded these, however.  

The latest change is that vets are now advising an additional vaccine which is more effective against these newer and more virulent strains of RHD2. This recently licensed vaccine can be given in addition to the normal combined vaccine, with at least a 2-week interval between the two.  

This vaccination became available in January 2025 and targets the classic form of RHD2 as well as the more virulent form. 

So, an updated vaccination strategy will often look like this – 

• Your rabbit’s core vaccine (combined myxomatosis, RHD1, and RHD2) is given from 5 weeks of age onwards 

• The new RHD-specific vaccine is administered at least two weeks later 

• Booster vaccinations are required annually, but every 6 months may sometimes be advised, particularly in higher-risk areas or multi-rabbit households. You will need to discuss this with your vet 

Using the two vaccinations in this way gives your rabbit the best possible defence against this disease. 

What else could I do to protect my rabbit? 

While vaccination is your rabbit’s best form of defence against RHD, it is important to recognise that no vaccine is 100% effective. 

Your rabbit will also be at increased risk of disease before they have completed their vaccination course. In some rare cases, a rabbit may have a medical condition that means they cannot be vaccinated. 

The Rabbit Association Welfare and Fund has advised all owners to consider the following –   

• If you are planning on attending a rabbit event or visiting somewhere with lots of rabbits like a wild rabbit habitat, you should change into alternative clothing and shoes that will not be worn around your own pet rabbits. We know that the virus can be readily spread on clothing and shoes, so these items should be washed immediately upon arriving home again. You can disinfect your shoes using a cleaning product effective against the virus (disinfectants that work against ‘cat flu’ are recommended) or a 1 in 10 solution of bleach – although this could cause staining of your shoes. Alternatively, change into a different pair of ‘indoor’ shoes when handling your rabbit. 

• Make sure to wash your hands for at least 2 minutes in warm, soapy water before handling your rabbits. Shaking hands with fellow rabbit owners or handling other rabbits could cause the spread of the virus. 

• Quarantine any shopping you have bought for your rabbits. Inorganic items like plastic should be left for 2 weeks before giving your rabbit access, or 3 months for any cloth material, bedding, etc. Things like fleece beds could be washed on at least 60 °C or 90C if they can handle it. 

In addition to this advice, you should also – 

• Be extremely careful when accepting second-hand equipment for your rabbit. Thoroughly clean off any organic material (bedding, faeces, and food) before disinfecting and quarantining it. 

• New rabbits should be quarantined away from existing rabbits for at least 2-3 weeks before introductions can start. 

• Maintain good hygiene in your rabbit’s enclosure and with their accessories, cleaning and disinfecting them regularly. 

• Use a fine mesh to limit insect access into your rabbit’s enclosure, as these can also spread the disease. 

• Fleas can also spread the disease, so make sure that your rabbit is protected against this parasite. Any cats or dogs in your home should also have regular flea control. 

• Rabbit-proof your garden to try and prevent wild rabbits from entering and carrying infection in. 

If your rabbit is suspected of having died from RHD, then extreme care must be taken when introducing a new rabbit into that environment because the virus can remain present for months. Always speak to your vet for advice if you are not sure. 

Summary 

Sadly, RHD is not curable once your rabbit catches it, and for many rabbits, it is a death sentence. Vaccination is the best protection you can provide your pet, alongside some sensible biosecurity measures. Both indoor and outdoor rabbits are at risk from this virus. The rise of the more virulent form of RHD2 means that vaccination is now even more important than ever. 

Your vet will be able to discuss their vaccination protocol further with you and answer any questions you may have about this virus. Always contact them if you have any concerns about your rabbit’s health. 

Further Reading 

RVHD2 Update – RWAF 

Viral Haemorrhagic Disease of Rabbits – RVC