At Fairfield House Vets, we regularly review our vaccination protocols to make sure we’re offering the best possible protection based on the latest evidence and disease trends. As part of this, we’re making a change to the leptospirosis vaccine we use for dogs.
What is leptospirosis?
Leptospirosis is a serious bacterial disease and one of the four core vaccinations recommended for dogs, alongside parvovirus, distemper and infectious hepatitis. It’s most commonly spread through contaminated water or soil, particularly where wildlife such as rats are present, but it can also be passed through direct contact with infected animals.
Because the bacteria thrive in damp environments, dogs don’t need to be “country dogs” to be at risk — urban parks, puddles and gardens can all be sources of infection.
What do L2 and L4 actually mean?
There are several strains of leptospirosis. The name of the vaccine simply refers to how many strains it protects against:
- L2 protects against two strains
- L4 protects against four strains
Historically, two of the additional strains covered by L4 were mainly found in mainland Europe. However, these strains are now well established in the UK, meaning dogs here are increasingly at risk.
Because of this shift, the World Small Animal Veterinary Association (WSAVA) now recommends L4 vaccination for dogs in the UK, and most vaccine manufacturers no longer produce L2 vaccines.
What’s changing at Fairfield House Vets?
We are moving to the L4 leptospirosis vaccine so our patients are protected against the strains currently circulating in the UK.
If your dog has previously had an L2 vaccine, they will need:
- Two L4 injections, given 4 weeks apart, to ensure full protection
- The second injection will be free of charge.
Is the L4 vaccine safe?
We’re aware there is a lot of misinformation online about leptospirosis vaccines, particularly L4. It’s important to rely on evidence-based guidance and reputable sources.
The UK’s Veterinary Medicines Directorate (VMD) reviewed safety data in 2023 and reported that adverse reactions are rare for all leptospirosis vaccines:
- Fewer than 2 reactions per 10,000 doses for L2
- Fewer than 5 reactions per 10,000 doses for L4
Most reported reactions were mild, temporary allergic-type responses — something that can occur with any vaccine.
The L4 vaccine we use:
- Comes from the same manufacturer as our previous tried and tested vaccine, it is just a newer more protective version
- Contains the same low levels of stabilising proteins
- Is non-adjuvanted, meaning it does not include additives associated with increased injection-site reactions
In short, we would not expect an increased risk of side effects.
Does my dog really need it?
Yes. Leptospirosis is not only potentially life-threatening for dogs, but it is also zoonotic, meaning it can be passed to humans. By vaccinating your dog against more strains, you’re helping to protect:
- Your dog
- Your family
- The wider community
We base our recommendations on international guidelines and real cases we see locally. We would never advise a vaccine we didn’t believe was genuinely necessary.
If you’d like to discuss what this change means for your dog, our team will be very happy to help.
📞 Call Fairfield House Vets on 01825 764268
