Calicivirus (RHDV) - rabbit vaccination
Updated advice as of August 2022
Rabbit haemorrhagic disease virus (RHDV) is a virus that typically causes a rapidly fatal disease in European rabbits (Oryctolagus cuniculus). There are two types of RHDV present in Australia (RHDV1 and RHDV2). RHDV1 is has been used as a biological control agent to reduce the feral rabbit population in Australia since 1996 (the K5 RHDV1 strain was introduced in 2017). RHDV2 was first detected in 2015 in Australia. It is currently the strain causing most of the deaths in domestic rabbits.
Until recently, Australian veterinarians have been using the CYLAP vaccine to protect rabbits from RHDV disease, however, it only contains an RHDV1 strain. This has been why 6 monthly vaccinations were recommended, in order to maintain consistently high antibody levels to try to leverage some cross-protection against RHDV2, the current dominant RHDV strain in Australia.
Filavac VHD K C + V is an inactivated bivalent vaccine for rabbits against RHDV (Rabbit Haemorrhagic Disease Virus) types 1 and 2, and has just been licenced for use in Australia.
From the manufacturer: ‘FILAVIE has performed a genetic comparison of the nucleotide sequence of the RHDV2 strain included in the vaccine FILAVAC VHD C+V K and the that of the RHDV2 strains circulating in Australia, investigating the degree of identity of the VP60 gene sequence (responsible for immunogenicity) of the above strains. A very high percentage of nucleotide identity appears between this the vaccine strain and the RHDV2 strains (96%) detected in Australia, confirming that the strains belong to the same variant and that the structures of their VP60 are very close from a genetic point of view. This clearly demonstrates that the vaccine will protect against the RHDV2 Australian strain. The report of this genetic comparison was reviewed and approved by APVMA, as part of the regulatory dossier to authorize the use of the vaccine in Australia (more particularly as a scientific justification in support of the use of overseas product and data in Australia).’
A single vaccination from 10 weeks of age provides immunity 7 days later and lasts 12 months. UPAV still recommends regular health checks for rabbits and notes that 6 monthly health checks are beneficial in catching health problems early.
Filavac can be used from the next vaccination due date. i.e. 6 months after their last Cylap vaccination, or earlier in specific circumstances such as an RHDV2 outbreak, given that Filavac has a specific RHDV2 strain component. Once a rabbit has been dosed with Filavac, it will be due for a booster with Filavac 12 months later. The dose of FILAVAC VHD C+V K is 0.5 mL, and the adjuvant is not oily. Side effects for the Filavac vaccine include fever, lethargy, and a transient subcutaneous nodule at the vaccination site.