LEPTOSPIROSIS AND VACCINATION

We no longer use the Leptospira L2 vaccination at Hawkinge Veterinary Surgery because the main supplier of L2 vaccines in the UK has stopped manufacturing this vaccine.

We understand that one of the reasons some of our clients joined us was because we continued to use the L2 vaccine when other vets had moved to the L4 vaccination.

We know that those clients will be disappointed that we are no longer using L2 and will be worried about using L4. For that reason we have produced a more detailed discussion about the disease and vaccination.

Leptospira is transmitted…

• By swimming in stagnant or slow-moving water, drinking from puddles or ingesting food that has been contaminated with rat urine.
• Through an open wound that is in contact with infected water.

Places that are high risk of infection are stables, farms and ponds.

It is an uncommon disease. We did not treat a confirmed Leptospirosis case since opening in August 2016 to December 2024

Leptospirosis is a zoonotic disease which means it can infect humans

The Science (sort of)

What do we mean, L2 and L4 vaccines ?

It refers to the vaccines used to protect against a nasty but uncommon disease in dogs called Leptospirosis caused by an organism called Leptospira. Hence the L.

The 2 and 4 refers to the number of variants of the Leptospira that can cause disease.

We all know that covid has a number of variants, Leptospira also has a number of variants.

Over recent years there has been debate between vets whether we need to vaccinate our dogs against 2 of the strains or 4 of the strains of Leptospira. For boffins reading this, the strains in L2 vaccines are called Icterohaemorrhagiae and Canicola and the strains in L4 vaccines are Icterohaemorrhagiae, Canicola, Australis and Grippotyphosa

The History of Leptospira vaccination

Vaccines containing Leptospira Icterohaemorrhagiae and Canicola were the first that were developed and have been around for decades. They have been tried and tested on millions of dogs worldwide.

About 10 years ago, there was a study published about the cases of leptospirosis in dogs in specifically in the Bristol area. These were found to be caused by Australis.

At that time, a number of European countries were already using L4 vaccines and some manufacturers decided to introduce this L4 vaccine into the UK alongside the L2 vaccines. Some vets switched to it immediately, others like ourselves, had a more cautious approach to this trend.

In early 2025, we decided to stop using L2 vaccines and now only use L4 vaccines.

We have not taken this decision lightly and it has caused some healthy debate amongst our staff. Some have only ever used L2 and some only ever used L4.

However, the decision on which vaccine we should continue to use has been taken out of our hands for the following reasons: -

1. The main manufacturer of L2 vaccines announced in October 2024 that they will no longer manufacture L2 vaccines and will only supply L4 vaccines. We predicted this would eventually happen and have told clients who have strong views about L2 and L4 that this would probably be the case.
2. We have decided that the remaining L2 vaccine on the market is not suitable as it does not offer early enough socialisation for our puppies (see later)
3. There is now more research and evidence from referral centres that Leptospira cases of all 4 strains are becoming more common in the UK. Vets must make decisions for our animals following evidence-based medicine and not on a personal preference, whim or bias. We must go with the evidence.
4. More clients are travelling abroad and they should use L4 vaccines as the 4 strains are more common in certain parts of Europe than in the UK

 

What about the side effects of L4 vaccines?

Public (and vet) resistance to change aided by media frenzy led to a number of unsubstantiated reports in the press and social media that L4 was harmful to dogs and even caused deaths or nasty long term diseases.

Vets are obliged to report abnormal reactions following any licensed drug or vaccine given to an animal. They report these to the Veterinary Medicines Directorate (VMD). The VMD is an independent body (independent of drug companies and vets). Reported reactions to L4 and L2 vaccination were not classified. They were simply recorded as a report of a reaction and would have included death, anaphylactic reactions, temperature, pain at vaccination site, depression after vaccination etc

In December 2023 the VMD published its findings that for L4 vaccines there were fewer than 5 reports of a reaction for every 10,000 vaccinations administered and for L2 there were fewer than 2 reports of reactions for every 10,000 vaccinations administered. For L4 this is really quite a low rate of reactions.

We fully understand that if it is your pet, then no rate is low enough. But all drugs and vaccines have the inherent risk that an abnormal but recognised reaction can happen. We believe the benefits of vaccination outweigh the very low possibility of reaction.

As with all vaccination programmes we all rely on herd immunity for protection and contributing towards this herd immunity is when a significant proportion of the population (in this case our pets) are vaccinated. The vaccinated diseases become so uncommon that there is a tendency to minimise the usefulness of annual vaccinations. Some of us are old enough to have lived through the horrendous Parvo virus outbreaks that killed puppies but is now a rare disease because of effective vaccination.

Our new vaccination schedule for puppies from 2025

PUPPIES

8-10 weeks old

First vaccination against Distemper, Hepatitis, Parvovirus and the 4 strains of Leptospira (L4)

10 weeks old (or 14days after 1st vaccination)

Second vaccination against Distemper, Hepatitis and Parvovirus.

11 weeks old (or 7 days later)

Your puppy will be fully vaccinated against Distemper, Parvovirus and Hepatitis but not Leptospira until its second vaccination.

Puppies will be allowed out**

12 weeks old (or 28days after the first L4 vaccination)

Second L4 vaccination. NOTE: there is no leeway from the manufacturer in the 28days between vaccinations. This is the same for all L4 vaccines regardless of the manufacturer.

The second leptospira vaccine must be exactly 28days after the first

This is based on the research all the drug companies have done when checking how well the L4 vaccines work and they have found that the response following the second vaccination will be much less predictable if it is not given exactly 28 days from the first. If you do not attend exactly 28 days after the first L4 you will have to start all over again with another L4 vaccination and yet another L4 vaccination exactly 28 days later. This of course will delay when you can safely allow your new puppy to go wherever its nose leads it to! It will also result in an additional cost for the L4 course of two injections to be repeated.

15weeks old (or 7days after last vaccination)

Your puppy is now fully vaccinated and can go wherever it wants !

At this point we need to warn you that the response to vaccination is determined by an animal’s own body and that some individuals will not have a good response to a vaccine and continue to be susceptible to a disease. This is typical of all vaccines, whether or not they are for humans or animals and is very rare. If this concerns you, there are blood tests available to check response to vaccination.

Remember also that immunity from vaccination doesn’t last forever and vaccinations need to be repeated throughout your pet’s life. Again, an alternative to vaccination would be annual blood tests to check levels of immunity.

**Why allow puppies out and about before they are fully vaccinated against Leptospira?
We believe that the very low risk of your puppy getting Leptospirosis is far outweighed by the huge advantages a puppy will get from socialising as soon as possible with other dogs, meeting strangers, encountering cars etc. It is well researched that there is a window of opportunity for pups to develop good social skills and this window begins to close down after 10 weeks old

It is unlikely your pet will lick rat urine, it is more likely they will swallow it when splashing about in water containing Leptospira. So, steer away from stagnant water of any description and definitely don’t visit farm yards, horse stables etc until three weeks after the second L4 vaccination. Check your garage and outbuildings. Keep anything edible to a puppy locked away from any possible rat contact. Pick up any bird food dropped from feeders that would be accessible to your puppy. This is sensible advice for any home owner, with or without a puppy.

Remember, Leptospira is an uncommon disease. However, you must decide what is best for you and your puppy. The alternative, if you have any doubt is that you must keep your puppy confined to your home and ideally, not even go into the garden until three weeks after its second leptospira vaccination. Thus avoiding all possible contact with rat urine. We don’t recommend this because it will mean that your puppy doesn’t socialise during an important time in its life.

ADULT DOGS ALREADY VACCINATED

At their normal booster time your dog will receive its first L4 vaccination with any other vaccinations due and then exactly 28 days later its second L4. We recognise this is a nuisance and therefore have decided that for existing clients, the second L4 vaccination will be free of charge, courtesy of Hawkinge vet surgery.

ADULT DOGS WITH UNKNOWN VACCINE HISTORY

First vaccine of Distemper, Parvovirus, Hepatitis and L4. Then the second L4 exactly 28days after the first. Full immunity to L4 is 3 weeks after this second vaccination

NOTE: This is the same for puppies aged 10 weeks or older