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 licenced 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 reactions for all L2 vaccine products combined is 0.015%; for L4 vaccine products this figure is 0.069%.

In other words, the VMD has received fewer than 2 adverse reactions for L2, and fewer than 7 for L4, for every 10,000 doses sold. This includes every suspected adverse event reported, even cases that were considered unclassifiable or were later found to be unrelated to the vaccine.

The overall incidence of suspected adverse reactions for both L2 and L4 vaccine products is therefore considered to be rare.

Further information (PDF, 9.02KB, 1 page)

https://www.gov.uk/government/news/leptospira-vaccination-in-dogs