FOI release

FOI Request for Information on Adverse Neurological Reactions Following Nobivac L4 Vaccination

Published 19 August 2025

Request ATI1064

• The number and type of reported adverse neurological reactions related to Nobivac L4, especially those involving limb paralysis or progressive neurological decline.
• Whether your database includes any clinical case summaries, diagnostic patterns, or treatment suggestions based on reported outcomes.
• Whether there are recognized patterns among affected dogs (e.g. small breeds, younger age, etc.), as some articles suggest a predisposition in those groups.

Our reply

Nobivac Nobivac L4 Suspension for Injection for Dogs is a veterinary medicinal product (VMP) used in dogs.

All medicines whether for human or animal use come with risk, and the benefits of use in wider populations need to outweigh the potential risks. Information on adverse events that have been known to occur following administration of a particular product are summarised in sections 3.6 of the Summary of Product Characteristics (SPC). The SPC is a document describing the properties and the officially approved conditions of use of a medicine. The SPC and associated product information are updated as new information is available, and the latest version of an SPC can be found on the EMA’s Veterinary Medicines Website. The SPC for Nobivac L4 is available at the following link: Nobivac L4 (–) - Suspension for injection UPD.

Please be aware that the data we have provided below are not subject to independent verification and the Veterinary Medicines Directorate (VMD) does not guarantee their accuracy. We have included reports from where more than one product was used, reports when the product was used off-label, that is using a medicine in a way that is not specified on the product’s label, or reports where, on further evaluation, there may have been other reasons for the adverse event occurring.

The data provided below relates to adverse events occurring in the United Kingdom. Adverse events occurring in different countries may have different trends or risk factors, and therefore it is important to check the data and the correct version of the SPC for your country. We would advise looking at the data available at European database of suspected adverse drug reaction reports and contacting the European Medicines Agency for data relating to European countries (Send a question to the European Medicines Agency (EMA)).

A summary of the clinical signs is provided below. All adverse events submitted to the VMD have their clinical signs coded using the Veterinary Dictionary for Drug Regulatory Activities (VeDDRA). We have provided an overview of the breakdown of neurological adverse events by High Level Term (HLT) which is one of the hierarchical levels of VeDDRA. We have also provided a breakdown of adverse events involving potential limb paralysis by Low Level Term (LLT) which is another hierarchical level of VeDDRA. Please be aware that one animal may have more than one clinical sign belonging to the same HLT, and each adverse event report may contain more than one animal. Therefore, the total number of occurrences of clinical signs does not equal the total number of animals reacted.

VeDDRA High Level Term	Number of reports
Neuromuscular disorders	775
Coordination and balance signs	741
Convulsions and epilepsy	462
Impaired consciousness	349
Central nervous system disorders	171
Sensory abnormalities	120
Paralytic and paretic disorders	110
Mental impairment	92
Neurological disorders NOS	17
Peripheral neuropathies and neuritis	10
Congenital neurological disorders	9
Central nervous system vascular disorders	2
Spinal cord and spinal nerve root disorders	2

VeDDRA Low Level Term	Number of reports
Collapse of leg	20
Hind limb paresis	19
Hind limb paralysis	18
Quadriparesis	10
Paresis	5
Flaccid paralysis	4
Paralysis	4
Hemiparesis (weakness L or R side)	3
Paralysis NOS	3
Paraplegia	3
Monoparesis (paralysis of limb)	2
Paraparesis	2
Deterioration of muscle function	1

We are unable to provide the number of adverse event reports involving progressive neurological decline as there is not a specific VeDDRA term that covers all situations where progressive neurological decline could occur.

Our database includes clinical case summaries, however we are unable to provide a copy of each case summary as retrieving this information would be a significant undertaking, therefore we are refusing this request as you currently frame it under Section 12(1) of the FOIA because we estimate that the cost of complying with the request would exceed the appropriate limit, which currently stands at £600.

The VMD does not give individual clinical advice, as the specific treatment of an animal is best determined by the veterinary professional under whose care they fall. For advice on specific cases, general product advice or when considering off-label use, we advise veterinary professionals to contact the Marketing Authorisation Holder (pharmaceutical company).

Diagnostic criteria, investigation details, and treatment provided to an animal are not mandatory fields in the VICH adverse event report format, and therefore the VMD does not hold this data in an easily retrievable format.

Any confirmed information regarding warnings and precautions for specific groups of animals is located on the SPC, if any specific trends regarding at risk animals are identified then the SPC would be updated. The Veterinary Medicines Directorate (VMD) also publishes any updates regarding Leptospira vaccines at the following link: Leptospira vaccination in dogs - GOV.UK