Veterinary Medicines Directorate
Figures updated 15 December 2023
The VMD is aware of media reports and concerns raised on social media following cases of serious adverse events in dogs given the vaccine containing four strains of Leptospira bacteria.
The VMD receives adverse event reports from veterinary surgeons, animal owners and marketing authorisation holders (MAH).
We would like to reassure vets, and through them dog owners, that we are constantly reviewing adverse event report data to ensure that the benefits of each UK licensed veterinary medicine product outweighs the risk posed by their potential side-effects.
There are a number of vaccines authorised in the UK containing either two (L2) or four (L4) strains of Leptospira. Based on the most recent periodic safety update report data received for each product, the incidence of adverse animal events for all L2 vaccine products combined is 0.016%; for L4 vaccine products this figure is 0.045%.
In other words, the VMD has received fewer than 2 adverse events for L2, and fewer than 5 for L4, for every 10,000 doses sold.
The overall incidence of suspected adverse events for both L2 and L4 vaccine products is therefore considered to be rare.
This includes all reports we received, including reports where more than one product was used, reports when the product was used off-label (i.e., not according to manufacturers recommendations), or reports where, on further evaluation, there were other reasons for the adverse reaction occurring.