30/12/2020
This post from a vet
Roger Meacock MRCVS
I am writing a special section on Lepto vaccination because I frequently come across owners who have thought about vaccination with limited access to information and have decided that of all the diseases their dog is likely to encounter Leptospirosis is the one and that they should therefore keep this vaccine going beyond all others. The following information might cause you to change your mind!
Kansas University reports that the Leptospirosis vaccine is THE major cause of vaccine reactions, so much so that they consider the risks outweigh the benefits. It is no longer considered a core vaccine and they even recommend it should not be given to puppies.
Another study found the vaccine highly immuno-suppressive and recommended that the vaccine should not be given in conjunction with other vaccines (it is currently in the UK).
The Leptospirosis vaccine does not protect the dog from being infected with the disease; it just minimises the clinical symptoms. Hence there seems to be/have been a real risk of vaccinated healthy dogs shedding the spirochetes to other dogs and humans.
Although one manufacturer has recently claimed it has a vaccine to prevent this, the clinical study conducted to test the vaccine was based on a sample of only 6 dogs which statistically is a study so narrowly based that it cannot be scientifically credible. The duration of immunity measurable by titre induced by the Leptospirosis vaccine can be as little as a few months yet the advised interval for boosters is 1 year, which it seems has been an entirely arbitrary recommendation.
By inference it may well be therefore that even vaccinated dogs are not protected as their owners expect.
There is little protection between serovars (types).
Use of the vaccine in the USA has led to a shift in the serovar population such that the serovars now infecting dogs are not the ones used in the vaccines.
I think it is logical to assume this is true also in the UK.
Are we therefore now vaccinating against a disease that barely exists in the form vaccinated for?
The vaccine efficacy seems between only 50 -70%, depending on the author.
The new L4 vaccine is currently being pushed very hard in the UK and scare stories about leptospirosis diagnosis and disease are rife. The truth about the L4 vaccine is as follows ...
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The L4 vaccine covers the 2 serovars in the old vaccines as well as 2 new serovars L3 and L4. There are quite a few serotypes within each serovar and there is cross-protection between serotypes within each serovar but, as stated above, not between the different serovars. The L3 serovar does NOT occur in the UK as the intermediate host is a type of vole that doesns't occur in this country.
It is more widespread in Europe and the U.S. So that's a quarter of the new vaccine we don't need already.
The L4 serovar has been so far diagnosed in 1% of cases referred to the Animal Health Trust labs. Of course not all cases get tested but even so it would seem that the new vaccine gives little additional benefit over the older ones.
It would appear that the reason why the vaccine has been launched in the UK when the European and U.S. markets are the real targets is that it makes sense for the manufacturer to produce enough of the vaccine and market it to the UK too knowing that because vaccine uptake in the UK is generally good, we provide a good opportunity to get more data on adverse reactions etc.
