The rhd virus isn't just in the states. It actually just started being more prevalent here in the US in the past year. RHD1, RHD2, and myxo have been common viruses in the UK for a few decades. So it's much more common there and in Europe then it is here. Which is why vaccinations are common there and easy to have done, unlike in the US.
If you want to have your rabbit outside, I would first make sure the rabbit is up to date on the rhd1, rhd2, and myxo vaccinations. If your rabbit is, some rabbits can be leash trained using an H harness, and some will totally freak out and should never have a leash and harness on them as they could injure themselves.
Leash training can pose a risk of severe fear response in some rabbits and possible shock and cardiac arrest could be the result. If it is attempted, it should start indoors in a safe and controlled environment, allowing the rabbit to slowly get used to the feel of having a harness on. I would keep a short tight leash so that if the rabbit does freak and tries to run, the leash won't snap tight and yank back on the rabbit risking injuring them. And if the rabbit does freak, leash training should stop immediately.
Keep in mind though, having a harness and leash on a rabbit doesn't mean you can take them out on a walk. It's more they walk you. You stand there, they hop a few steps, you follow. If leash training is attempted, it needs to be done with extreme caution. Personally I find it much easier to just set up a playpen for them to hop around in(continually supervised if not in a predator secure pen).