And, i also really really want to advise against just googling something and then reading the first few pages.
What one needs to ameka sensible informed decision about anything is to know that you are looking at peer reviewed up to date papers.
I googled lepto and the first page of results I got were petinfo type websites that are just the opinion of a person, amybe a vet, maybe not.
There was ONE paper in that group- about raccoons and lepto in man in washington.
If you look, you'll see the difference. To get an sceintific article into a reputable journal one needs to submit it to the journal, It is then read and discussed by a number of other professionals who question and check the results and only if it is a viable paper will it be included in the publication.
This is a far cry from somebody posting some stuff on an internet page- which we could all do very easily.
Yes, there are debates about whther or not to vaccnate every year, there are discussions about which diseases to vaccinate against in any given animal. the drug companies so far still recommend year vaccinations- and many vets follow the manufactuers' recs to the letter. imagine if they didn't and your pet died of one of the disease that can be vaccinated against- you'd be livid.
It's a mine field- honestly, there's been very big discussions here and in the USA.
And then biggest, most important advice I can give on an internet forum is that these diseases do exist. Animals (and people in the case of lepto) do die from thses illnesses each year.
Your pet may be massivley at risk if for example it is a puppy or young unvacciinated dog and is from an unvaccinated mother and you bring it to live in certain areas of (eg) London and then your bring in some dog poo on your shoes or let the puppy out in the street by accident. This is a classic parvo situation in my experience.
If your dog is 7yrs old and goes out in the filed in the back of your garden and rarely meets any other dogs and had its first vaccs, then it probably isn't at such a high risk. But if you live near water, and there's alot of rats then maybe it is at risk of lepto- the sort we cna and the sort we can't vaccinate for...
I could go on...
The pont I'm trying to make is alot of you haven't had your pets vaccinated and the risk for your pet is low, so it's probably fine. But you didn't knwo that specifically.
Your advice may mena that somebdoy else decides not to vaccinate their new puppy and then it dies in a pool of bloody vomit and diarrhoea in a year's time- but ypu'll never know that is how it worked out for that dog.
Speak to your vet and take advice about the disease risks in the area you live in... and evaluate the "advice" you find on the net- look for proper papers and read them as critically as you can.
It takes 5 years to train as a vet and we aren't all money grabbing gits- most of us just want you to have a nice life and keep your pets as healthy as we can.