RVHD2 HV FAQ April 2025

RVHD2 ‘HV’ strain and vaccine FAQ for rabbit owners and guardians.

We have been communicating about the new RVHD2 ‘highly virulent’ strain for several months now. There is a licenced vaccine that offers protection against this strain. We are not legally able to use the product name of the vaccine, but we have also been communicating with vets and vet practices, so you should be able to discuss this with them. As with any new disease threat, there is a lot of worry and lots of questions so here are the ones that we have been most frequently asked.

You can also read more about this on our website in the vaccination section.

Q1 – Why do I need to give two vaccines now?

A1 – “Highly Virulent” Strains of RVHD2 have been reported in Continental Europe. Only one vaccine is licenced to protect against these, and so we recommend that your rabbits be given a dose of that in addition to a vaccine that covers both RVHD and myxomatosis.

Q2 – Is there any evidence that the HV exists?

A2 – There is certainly published proof that different strains, some of which are designated HV, are present in Europe. The new vaccine has a licence specifically to cover HV strains, for that very reason.

Q3 – Is there any evidence that the HV strain is in the UK?

A3 – No, but this is because there is no active surveillance program for this disease, and there is, currently, no commercially available test to distinguish Classical RVHD2 from HV strains.

Q4 – Are the vaccines safe to give 2 weeks apart?

A4 – No work is ever carried out on the safety of vaccines from different companies given together. So, the industry standard has long been to advise that they are given a minimum of 2 weeks apart. Suppose you want to be even more sure they are safe for your rabbit. In that case, they can be given further apart than 2 weeks, with the only downside to that being that one would wish your rabbits to be protected against all diseases as soon as possible, which this delays happening.

Q5 – Will I be overdosing on my rabbit’s vaccines?

A5 – In the study carried out by the manufacturers of the current main vaccine, two rabbits out of a test group of 10 totally failed to respond to the vaccine and had no protection. When they were challenged with RVHD2, they died. We feel that having an additional vaccine will increase rabbits’ immunity and that the risk of any “over-vaccination” is outweighed by what would, at present, appear to be significant “under-vaccination”.

Q6 – Is the new vaccine safe, properly tested, etc?

A6—It has received full testing and approval, the same as any other vaccine or medical product for animals. Concerns about it being new can also be addressed by pointing out that this vaccine is an updated version of a previous vaccine made by the same company, which was effective against the classical but not the HV strain. This vaccine had been on the market and used for decades.

Q7 – When is the new vaccine available?

A7 Now. However, initial supplies have been a bit erratic. We expect this to become smoother and easier to obtain in all dose sizes soon.

Q8 – Have RVHD deaths increased because of the new strain?

A8 – Unknown, but it would help if the manufacturer could be transparent with their data on this and a number of other areas. We (RWA&F and associated individuals) have set up surveillance on this and other areas to attempt to gather information that would help rabbits in the UK in the future. We also know that rabbits vaccinated by the ‘triple’ vaccine have died, as mentioned in Q5.

Q9 – What is the cost of the new vaccine?

A9—We are not permitted to share this information. You should check directly with your veterinary practice of choice. Note that not all vets stock this vaccine, and prices will vary depending on package size, number of rabbit clients, and other factors.

Q10 – What is the ideal vaccine schedule now?

A10 – We cannot give specific schedules out as this is an area to discuss with your own vet. We would suggest that both vaccines given, at least 2 weeks apart, provide the most comprehensive cover for rabbits in general, but that the protocol for individual rabbits should be determined after discussion between you and your vet

Q11 – What if my rabbit has health problems, like EC; will a double vaccination be risky?

A11—We cannot provide specific schedules as this is an area you should discuss with your own vet.

Q12 – Will my rabbit be off-colour after vaccination?

A12 – The new vaccine is an ‘inactivated virus’ so the rabbits will not be vaccinated with a live version of. If any rabbits seem off colour after being vaccinated with the RVHD HV vaccine it is more likely due to it challenging their immune system, and the vast majority of rabbits recover in a short space of time.

However, if your rabbits have any underlying health conditions, anything that challenges their immune system can make it flare up. They could have underlying health conditions you are unaware of, of course, because rabbits are good at hiding them. So, for rabbits with health conditions or who are elderly, you need to discuss with your vet and weigh up the risk of not vaccinating versus the short-term effects on their immune system.