Nobivac Lepto 4
Information and points owners may wish to discuss with their vet
How leptospirosis spreads
Infected animals can shed Leptospira bacteria in their urine. Dogs may be exposed through infected urine, contaminated water, wet soil or mud.
The bacteria can enter through the mouth, nose, eyes or damaged skin. Rats and other wildlife can carry and spread the infection, although an infected dog can also shed bacteria.
What is Nobivac L4?
Nobivac L4 is a prescription-only vaccine intended to provide protection against four important Leptospira serogroups:
- Canicola;
- Icterohaemorrhagiae;
- Australis; and
- Grippotyphosa.
Older L2 vaccines generally provide protection against Canicola and Icterohaemorrhagiae. An L4 vaccine adds protection relating to Australis and Grippotyphosa.
Vaccination schedule
According to the current UK product information, Nobivac L4 can be given to dogs from six weeks of age. The primary course consists of two injections given four weeks apart.
- The first injection can be given between six and nine weeks of age.
- Where a puppy is likely to have a high level of maternally derived antibodies, the first injection is recommended at nine weeks.
- The second injection is normally given between ten and thirteen weeks of age.
- The stated onset of immunity is three weeks after completion of the primary course.
- The stated duration of immunity is one year, with annual revaccination recommended while protection is required.
Concerns owners may wish to discuss
Some owners remain concerned about the use of L4 vaccines and prefer to discuss the following points with their vet before consenting:
- whether all four serogroups represent a significant risk in their particular area;
- whether their dog’s lifestyle exposes it to standing water, watercourses, farms, rodents or other potential sources of infection;
- whether an L2 or L4 vaccine is the most appropriate choice for their individual dog;
- any previous reaction to vaccination or history of immune mediated disease;
- the age, breed, size and current health of the dog;
- whether several vaccines should be administered during the same appointment; and
- how the vaccination timetable may affect safe early socialisation.
Owners should be able to discuss the benefits and possible risks with their veterinary surgeon and agree upon a vaccination plan tailored to their individual dog.
Clarifying some frequently repeated claims
| Claim or concern | Current product information |
|---|---|
| Nobivac L4 cannot be given before nine weeks of age. | It is licensed from six weeks. Nine weeks is recommended as the starting age where maternally derived antibodies are likely to be high. |
| Nobivac L4 is not compatible with the main puppy vaccines. | Official product information permits it to be mixed and administered with specified Nobivac vaccines containing distemper, adenovirus, parvovirus and/or parainfluenza components. |
| A puppy receiving Nobivac L4 cannot be protected against parainfluenza. | The product information specifically includes compatible Nobivac combinations containing a canine parainfluenza component. |
| The additional L4 serogroups are not relevant anywhere in the UK. | The risk can vary according to location and lifestyle. The VMD advises vets and owners to consider the local disease risk when choosing between available vaccines. |
Possible adverse reactions
As with any medicine or vaccine, adverse reactions are possible. The current product information lists temporary injection-site swelling, a small nodule, soreness, a raised temperature, reduced activity and reduced appetite among the recognised reactions.
Hypersensitivity reactions, including anaphylaxis, and certain immune-mediated conditions are listed as very rare. A severe allergic reaction requires immediate veterinary treatment.
In March 2026, the Veterinary Medicines Directorate reported that the overall incidence of adverse-event reports was approximately 0.016% for L2 products and 0.040% for L4 products. Reports involving death, including euthanasia, were recorded at approximately 0.0017% for L2 and 0.0033% for L4.
When to contact your vet
Contact your vet if your dog seems unwell after vaccination. Seek urgent veterinary attention if your dog develops difficulty breathing, facial swelling, collapse, repeated vomiting, very pale gums or any other severe or rapidly developing symptoms.
Owners and veterinary professionals can report a suspected adverse event to the vaccine manufacturer or directly to the Veterinary Medicines Directorate. A report can be made even if it is uncertain whether the vaccine caused the reaction.
Making an individual decision
The Veterinary Medicines Directorate states that the benefits of authorised L2 and L4 vaccines outweigh their risks. It also advises that vaccination decisions should be tailored to the individual dog, taking account of local disease risk and the potential risks described in the product information.
Owners who have concerns should ask their vet to explain the difference between L2 and L4, the risk of leptospirosis in their area and why a particular product is being recommended for their dog.