FAQ for Medgene Lab’s RHDV2 Vaccine

New US-developed RHDV2 Vaccine Receives USDA Emergency Use Authorization

House Rabbit Society gladly acknowledges the Emergency Use Authorization (EUA) of Medgene Labs’ recombinant vaccine against rabbit hemorrhagic disease (RHDV2). This FAQ is designed to help bunny caregivers understand this vaccine and its role in protecting rabbits from this disease. House Rabbit Society strongly recommends vaccinating all rabbits to protect them from this deadly disease with any of the available vaccines – the vaccines are remarkably safe and prevent the vast majority of illness and death.

So far, 44 State Veterinarians and District of Columbia have already authorized emergency use of the new RHDV2 vaccine, and Medgene anticipates approval in more states in the near future. States that have still not accepted the EUA for Medgene’s vaccine include Maine, Massachusetts, New Hampshire, Vermont, Hawaii and Alaska. See “Vaccine Accessibility” for the current list of authorized states.

FAQ: Medgene RHDV2 Vaccine

What kind of vaccine is it? 

Medgene’s RHDV2 vaccine is made of a single “subunit” or part of the RHVD2 virus that, when administered properly, results in a robust immune response in the rabbit which we observe as near-complete resistance to RHD. More vaccine information from Medgene is available here.

How is Medgene’s vaccine administered?
This vaccine is administered in 2 subcutaneous doses, 21 days apart and (according to preliminary reports) once a year thereafter to maintain the advertised efficacy.

How long after my bunny is vaccinated will the vaccine be effective?
Properly administered, Medgene’s vaccine will be fully effective 35 days after the first dose and 14 days after the second injection. Data on the booster is not yet available. The vaccine’s advertised efficacy requires both shots in the 2 dose regimen.

How effective is this vaccine?
In Medgene’s preliminary tests, all vaccinated rabbits survived a “challenge” which means that researchers intentionally injected the live virus that causes RHD into rabbits who had been fully vaccinated with Medgene’s vaccine; 100% of vaccinated rabbits survived this challenge in laboratory conditions.

What does Emergency Use Authorization (EUA) mean?

The vaccine is not yet fully licensed by the USDA, but instead has been given Emergency Use Authorization. As part of the EUA process, Medgene has demonstrated preliminary vaccine efficacy and safety. Additional efficacy and safety studies are underway as the company works towards a full product license.

EUA makes Medgene’s recombinant vaccine available for any State Veterinarian in the USA who wishes to distribute the vaccine in their state. This authorization does not require confirmed cases of rabbit hemorrhagic disease in that state.

Is this vaccine safe?
Additional data must be generated by Medgene and must meet final safety criteria for full approval, but Medgene’s vaccine has undergone extensive preliminary testing and these data do suggest this vaccine is safe!

What are possible side effects to this new recombinant RHDV2 vaccine?

So far, Medgene safety testing studies report only rare instances of swelling at the injection site which resolve within 48 hours. Other possible side effects are a temporary slight fever and/or lethargy for 1-2 days.

Who decides if the new vaccine may be used in my state?

State Veterinarians authorize and direct vaccine use in their state, including recordkeeping and ID requirements.

Who can purchase the vaccine?

Under Emergency Use Authorization, Medgene Labs is distributing vaccine ONLY to licensed veterinarians in authorized states. Licensed veterinarians should contact Medgene Customer Service at (605) 697-2600 for more information on approval status in their state and how to purchase vaccine. 

Does Medgene’s new vaccine require the use of rabbits in its vaccine production? 

Rabbits are not used in the general manufacture of this vaccine. However, a limited number of rabbits are required to determine the safety and efficacy of the vaccine under federal law. Once this vaccine receives full authorization, no additional rabbits will be required to produce the vaccine. 

Can my rabbit be vaccinated with the new Medgene recombinant RHDV2 vaccine if previously vaccinated with Filavac or Eravac? 


Will the imported Eravac and Filavac vaccines continue to be available or will Medgene’s recombinant vaccine replace them? 

Since the US-made Medgene recombinant RHDV2 vaccine option is now available under EUA, the USDA will no longer approve new import permits for the two European RHDV vaccines. There will be a transitional period where veterinarians with supplies of Eravac and Filavac on hand will use up existing stock. Veterinarians’ existing USDA vaccine import permits will not be rescinded, but these permits will not be renewed once expired, nor will any new permits for imported RHD vaccines be issued. 

What does the new recombinant RHD vaccine cost?

Medgene expects the cost to be comparable to the two previously imported RHDV2 vaccines. Medgene’s vaccine is available for purchase by licensed veterinarians only at this time. These veterinarians and their practices will determine prices, so the cost may vary and might include required recordkeeping such as identification requirements (like microchips injected under the skin or tattoos), which may also be reflected in the veterinarian’s cost of vaccination.

How do I find out if the recombinant vaccine is authorized for use in my state? 

Check under “Vaccine Accessibility” on Medgene Labs’ website for an updated list of states that have authorized the distribution of the RHDV2 vaccine. lf your state is not listed, ask your veterinarian to reach out to Medgene’s Customer Service line directly at (605) 697-2600 or you can also inquire directly with the Office of the State Veterinarian.

If the recombinant vaccine is not yet authorized for use, let your State Veterinarian know of your interest in vaccinating your rabbit against RHD with this vaccine to encourage authorization.

Does Medgene’s RHDV2 vaccine “shed”?

No, this vaccine does not involve any infectious virus or whole viral particles and cannot cause viral shedding in vaccinated animals. However, if a vaccinated animal is infected with RHD, it may shed virus without showing symptoms.

Can the recombinant vaccine be given to pregnant or nursing rabbits?

Safety studies have not yet been completed for these rabbit populations, but the available data suggest this vaccine will eventually be approved for use in pregnant and nursing rabbits.

Do I still need to practice biosecurity if my rabbits are vaccinated?
Vaccination is the best protection you can give your companion rabbit. Continued biosecurity and decontamination is a good idea under most circumstances. For those choosing not to vaccinate their rabbit(s) for any reason, we recommend that strict biosecurity continue at all times. Caregivers should maintain strict biosecurity for immunocompromised rabbits as they still at significant risk before and after vaccination. We also recommend decontamination in the event of known or probable exposure – like if a family pet returns home with a wild or feral bunny. Those who are particularly risk averse may wish to continue some measure of biosecurity after vaccinating their rabbits, like removing shoes before entering the home. We highly recommend continuing biosecurity in areas where RHD is endemic and suggest contacting your local HRS chapter to learn more about the best practice for your region.

HRS asks that caregivers and chapters abide by the recommendations of their respective state veterinarian and any state and local ordinances pertaining to RHDV2 (linked here) when determining updated biosecurity practices. We understand that standards and risks vary widely between states where RHD is endemic and those where it has not yet been diagnosed. Some states’ policies may also differ based on the potential risk that RHD presents to threatened and endangered wild rabbits like the New England cottontail and the Lower-Keys marsh rabbit.

Do I need to sanitize vegetables for my vaccinated companion rabbit?
House Rabbit Society recommends rinsing all greens intended for your pet rabbit whether they are vaccinated or not, however heroic decontamination of greens involving sanitizing chemicals or extensive series of washes are not necessary for vaccinated rabbits.

Can my vaccinated bunny safely go outside?
Your local HRS chapter will guide you through the recommended steps to help promote the safety of your companion rabbits in the face of this ongoing disease while observing the appropriate practice for your region. Advice you receive regarding biosecurity practices might differ significantly from chapter to chapter and this is a result of regional differences in risk assessment and policy dictated by your state’s authorities.

What Government Is Doing Regarding RHD

Federal Government

USDA’s Center for Veterinary Biologics (CVB) granted Emergency Use Authorization/EUA to the experimental RHDV2 vaccine made by South Dakota-based Medgene Labs in October 2021 in an effort to make this vaccine available quickly while it undergoes the full USDA approval process.

State Government

Where authorized for emergency use by State Animal Health Authorities, Medgene’s RHDV2 vaccine can be sold directly to licensed veterinarians according to the State Veterinarian’s directives. More than half the US states have already authorized emergency use for Medgene’s recombinant vaccine, including some states without RHD outbreaks. Veterinarians should contact Medgene Labs directly to purchase vaccine  

This article was written by Iris Klimczuk and Christie Taylor, PhD. This article was reviewed by Anthony Pilny, DVM.

Published October 27, 2021. Updated January, 19, 2022.