New combined vaccine for Myxi and VHD

We are still getting enquiries about the new combined Myxi and RHD vaccine. The main concern expressed with the vaccine is the potential lack of protection against Rabbit Viral Haemorrhagic Disease Virus, in rabbits vaccinated with the new vaccine, if they have been previous vaccinated recently against myxomatosis, or have been infected with it and recovered.

This has been raised as a concern because some rabbits which had received previous Myxomatosis vaccination in trials in continental Europe did not develop immunity against RHD following vaccination with the Myxo_RHD vaccine. The vaccines used predominantly there are based on the myxomatosis virus, whereas the current one used here is based on Shope Fibroma Virus. This has led to some uncertainty until recently as to the level of protection so obtained, and the best vaccination protocol to be used in rabbits that have had previous vaccinations.

Recent work has been collated by the manufacturers, and demonstrates that at lower levels of vaccine content, there is not sufficient protection. However, at the levels that the vaccine contains, the vast majority of rabbits developed antibody levels that are protective against RHD. The vaccine is also known to produce cell immunity, in addition to antibody levels, which cannot be measured by blood tests, and these results are typical of an effective vaccine as used in other species.

The only way to examine the vaccine effectiveness further would be to perform challenge studies. This would entail taking vaccinated and unvaccinated animals and deliberately subjecting them to RHD virus, which would kill the unprotected ones. For ethical reasons this is not ideal, and would perhaps be especially unfortunate since the new vaccine has been made without the need to culture the virus in live rabbit liver, as is necessary with previous RHD vaccines.

Without wishing to endorse a specific product, we feel that vaccination against these 2 killer diseases is an important part of rabbit preventative health. Any tool which allows us to prevent death and suffering, especially when this is made easier and therefore more practical to achieve, by only involving one visit to the vets per year, is to be welcomed.

We will be covering this in more detail in the next issue of Rabbiting On, due out early May - to make sure you don't miss your copy please join and support our work, because A hutch is not enough:
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No, I will stick to separate boosters. Many thanks,

Jo