“A person not vaccinated has ONE RISK, catching the disease, where a vaccinated person has TWO RISKS; catching the disease and damage from the vaccine” - Judith A. DeCava

Understanding the Leptospirosis Vaccination

Leptospirosis, a widespread bacterial infection affecting numerous mammalian species, including dogs and humans, presents a multifaceted challenge, particularly in regions characterized by warm, humid climates and heavy rainfall. While vaccination against this disease is commonly advocated, recent insights into the risks associated with the leptospirosis vaccine for dogs necessitate a comprehensive analysis, integrating both empirical data and anecdotal accounts.

Manufactured by Nobivac MSD Animal Health, a subsidiary of Merck, the leptospirosis vaccine is available in two variants: Nobivac Lepto 2 and Nobivac Lepto 4. However, the efficacy and necessity of the Lepto 4 vaccine have come under scrutiny, especially in areas where certain serovars, such as L3, are absent, rendering a significant portion of the vaccine redundant.

Adverse Reactions

The lepto vaccine is associated with a notable incidence of adverse effects. Dr. Patricia Jordan, a veterinarian, has extensively documented cases of tumors linked to the lepto vaccine, particularly in combination vaccines containing leptospirosis. Additionally, kidney failure is a prevalent adverse reaction. Bacterial vaccinations can also trigger autoimmune diseases. The following is a selection of documented adverse effects associated with the lepto vaccine:

Anaphylaxis
Anorexia
Dermatitis
Infection with flesh-eating bacteria
Uncontrollable pruritus (itching)
Vomiting
Lethargy
Lameness
Vocalization
Fever
Dehydration
Polyarthritis
Kidney Failure
Liver Failure
Pancreatitis
Mast cell disease
Urinary tract infections
Diarrhea
Chronic weight loss
Enlarged spleen
Cancer
Enlarged lymph nodes
Death

Examining Post-Vaccination Trends and Assessing Natural Immunity

Empirical evidence from post-vaccination surveys, including those conducted by Canine Health Concern, unveils a perplexing trend: every dog in the study that contracted leptospirosis did so within a mere three months of vaccination. This raises critical questions regarding the vaccine’s purported role in mitigating disease severity versus potentially heightening susceptibility.

Intriguingly, studies have revealed that a substantial proportion of ostensibly healthy dogs harbor antibodies against various leptospirosis serovars, indicating prior natural exposure and potential immunity. Such findings challenge the conventional wisdom surrounding the necessity of annual vaccination, especially given the persistence of antibodies in some vaccinated dogs for extended periods post-inoculation.

Christopher Ball’s 2013 study, financed by the vaccine manufacturer, surveyed veterinary clinics across the UK and unearthed minimal reported cases of leptospirosis, prompting a reevaluation of the disease’s true prevalence and the rationale behind widespread vaccination campaigns.

Out of the 472 questionnaires distributed, only 89 were returned, representing a limited response rate. Among the respondents, the majority were veterinary practices that had not encountered any cases of leptospirosis in the preceding twelve months.

Merely 13 practices documented a case within this timeframe, with only five of these cases confirmed through laboratory testing. Additionally, 29 practices reported isolated instances of leptospirosis over the past 15 years. Notably, no practice reported more than a single case within a year.

Overall, the reported incidence of leptospirosis was exceedingly low, with only 5 cases documented among the 89 responding practices over the span of 12 months.

Anecdotal evidence gleaned from online communities, such as the “Nobivac Lepto 4 - Our Experiences” Facebook group, provides poignant accounts of adverse reactions experienced by dogs following vaccination. These range from mild symptoms, such as localized swelling, to severe manifestations like anaphylactic shock and, tragically, even death.

When the Lepto 4 vaccine was introduced in 2014, there were over 2000 adverse reactions, and 120 suspected deaths were reported to the VMD who regulate animal drugs in the UK.

The VMD states that adverse reactions are rare at 0.064% However; it’s gravely important to remember that adverse reactions are massively underreported.

Anecdotal evidence from online communities reveals adverse reactions experienced by dogs following vaccination, ranging from mild to severe. This underscores the need for transparency regarding vaccine composition and potential risks.

***(Taken from EMA veterinary pharmacovigilence 2016 report)***

What does the WSAVA say about Lepto?

The World Small Animal Veterinary Association (WSAVA) vaccine guidelines on vaccinating for lepto currently are the following;

“vaccination against leptospirosis should be restricted to use in geographical areas where a significant risk of exposure has been established.”

If you do decide to vaccinate for lepto, it’s very important to ask your vet that the vaccine be given separately from the DHP vaccine (vanguard have a vaccine that combines DHP with lepto which is a lot for a puppy’s immune system to deal with all at once) You should also be aware that the WSAVA recommend that toy breeds should NOT receive the lepto vaccination as they're at a significantly higher risk of an adverse reaction.

**Taken from page 18 of the WSAVA veterinary guidelines.**

Contrasting Perspectives on Vaccination

The dichotomy between the classification of leptospirosis as a non-core vaccine by the World Small Animal Veterinary Association and its elevation to core vaccination status by organizations like the British Small Animal Veterinary Association underscores the need for transparency regarding the underlying research and data informing such decisions.

Moreover, the composition of the leptospirosis vaccine as a killed vaccine containing adjuvants like mercury and aluminum hydroxide introduces additional layers of potential risk. Adverse reactions, spanning from immediate hypersensitivity reactions to delayed-onset vaccinosis, further complicate the risk-benefit analysis.

Contrary to prevailing perceptions, the risk of zoonotic transmission of leptospirosis from dogs to humans appears to be relatively low, with only a small number of reported cases annually, most of which are amenable to treatment with antibiotics. The absence of routine human vaccination against leptospirosis in the UK underscores the need for a nuanced reassessment of the imperative for widespread dog vaccination.

Christopher Ball’s 2013 study highlights minimal reported cases of leptospirosis, which also prompts a need for the reevaluation of the disease's prevalence and the rationale for widespread vaccination campaigns.

Treating Lepto

Now is an opportune moment to discuss the treatability of Leptospirosis. The antibiotic of choice for this condition is Doxycycline. Remarkably, even in cases of renal compromise, Doxycycline possesses the ability to sterilize the urinary tract of Leptospirosis infection. Furthermore, it can be safely administered to dogs with renal insufficiency and effectively clears the organism from the kidneys.

Given the diverse array of Leptospirosis serovars, coupled with variations in pathogenic strains and the inability of vaccines to ensure protection from infection, it seems prudent to reconsider the necessity of administering Leptospirosis vaccines to dogs.

The decision to forgo vaccination entails trade-offs, including avoiding potential adverse events such as renal failure within 48 hours of injection or enduring dermatitis and pruritus for up to four years. Instead, caretakers should remain vigilant for symptoms of Leptospirosis in their dogs and promptly seek treatment if necessary.

Antibiotic treatment yields rapid and effective results, with the possibility of human infection from their dog diminishing after the initial day of antibiotic therapy. Thus, early detection of Leptospirosis not only benefits canine health but also has implications for public health by reducing the risk of human transmission.

Doxycycline also serves as a successful prophylactic measure against human infection.

The practice of vaccinating against Leptospirosis presents numerous challenges. These vaccines fail to provide comprehensive protection against infection or renal colonization in dogs. Moreover, they exert minimal influence on the maintenance and transmission of the disease within animal populations. Paradoxically, Leptospirosis vaccines may even serve as a source of infection for humans in contact with vaccinated dogs afflicted with Leptospirosis.

Marketing Vaccines - A Corporate Con?

Beware of medical professionals who may lack expertise in Leptospirosis and instead rely on corporate marketing information. Much of the available information on Leptospirosis appears to be misinformation, often fuelled by marketers striving to boost revenue through vaccine administration, which can lead to adverse events.

Much like the Christopher Ball study (funded by MSD; the manufacturer of Nobivac Lepto), Pfizer-sponsored "scientific" papers on Leptospirosis, funded through "educational" grants, often lack evidence of vaccine safety or efficacy. These papers use language like "likely" and "appears" to exaggerate the benefits of vaccination, while downplaying adverse events.

Independent mechanisms for reporting vaccine reactions are lacking in the US, allowing drug companies and veterinarians to evade accountability. Pfizer, as a corporate mouthpiece, suggests vaccination based on vague claims of effectiveness, despite acknowledging weaknesses in vaccine development and diagnostic assays.

Moreover, Merial's Leptospira vaccines lack solid evidence of providing year-long immunity, with studies often conducted by conflicted parties and not using the vaccines in question. The push to vaccinate dogs for Leptospirosis in the UK was driven by drug companies seeking to create a market for their products, despite limited evidence of the disease's prevalence.

We have seen similar issues in human medicine, such as with GlaxoSmithKline's Hep B vaccine and more recently with the Covid vaccine.

Leptospirosis - The Fine Facts

Vaccinated dogs can shed lepto from the vaccine in their urine. This means they can infect other dogs because they are vaccinated. Therefore, annual lepto vaccinations can actually increase the incidence of lepto.

The WSAVA Guidelines suggest that vaccination against leptospirosis should be restricted to geographical areas where a significant risk of exposure has been established or for dogs whose lifestyle places them at risk.

Doxycycline, in the dose of 200 mg every week, has demonstrated efficacy of 95% against leptospirosis.

The leptospirosis vaccine is an inactivated (killed) vaccine, meaning it does not contain live pathogens. Instead, it includes adjuvants like mercury and aluminum hydroxide, which are intended to enhance the immune response upon vaccination. However, the presence of these adjuvants may increase the risk of adverse immune reactions in certain dogs.

A survey conducted by Canine Health Concern, examining the medical records of more than 3,800 vaccinated dogs, revealed a concerning trend: every dog diagnosed with leptospirosis in the study developed the illness within three months of vaccination. This raises the critical question of whether our vaccination practices are truly reducing disease severity or inadvertently increasing susceptibility to leptospirosis.

The WSAVA claims that leptospirosis vaccines “can be associated with adverse reactions” and are “associated with as many or more adverse reactions than occur for any other” optional vaccine on the market”.

In a study conducted in 2007, prior to the introduction of the Lepto 4 vaccination, researchers examined 1,241 healthy dogs, comprising both vaccinated and unvaccinated individuals. The findings revealed that 24.9% of the dogs had antibodies against 1-6 different serovars, indicating previous natural exposure and the development of innate immunity to these strains.

Leptospirosis, a zoonotic infection, has the potential to pass from animals to humans. Veterinarians often stress the importance of vaccinating dogs against leptospirosis to protect both our families and ourselves. However, known as Weil's disease, leptospirosis is rare in the UK. Human cases average around 50 per year, and it is not prevalent in dogs, despite the advice given by veterinarians. It's worth noting that there are no available vaccines for humans against leptospirosis.

The NHS website also states that contracting leptospirosis from our pets is "very rare." Considering the low incidence of leptospirosis cases, as indicated by Christopher Ball’s 2013 study, and the NHS's assertion of its rarity, this raises doubts about the necessity of vaccinating our dogs against this disease.

The WSAVA also states that the vaccine should not be given to toy breeds due to the higher rate of adverse reactions.

Conclusion and Recommendations

In conclusion, navigating the complexities of leptospirosis vaccination for dogs demands a meticulous examination of available evidence, encompassing both quantitative data and qualitative experiences. As custodians of canine welfare, it is incumbent upon pet owners to engage in informed decision-making, weighing the potential benefits of vaccination against the inherent risks. Only through a judicious synthesis of empirical insights and anecdotal narratives can we chart a course that safeguards the health and well-being of our cherished companions.

Leading immunologists such as Dr Ronald Schultz do not recommend the Leptospirosis vaccine. Dr Schultz does not vaccinate his own dogs even though he lives on a farm in a Leptospira endemic area. Infectious disease expert Dr Richard Ford has also stated publicly that despite living in an endemic area, he would not vaccinate his dog with the vaccine. As the WSAVA specifically states that the lepto vaccine should only be used in areas that are classified as high geographical risk - my personal recommendation would be to ask your local vet to confirm how many laboratory-confirmed cases of leptospirosis they have had and when - and assess the risk accordingly.

There is a government website where you can find the data for cases of leptospirosis in the United Kingdom however the last published report is from 2018 and it must be remembered that these are only reported cases and it’s crucial to note that a large number of cases go unreported. It’s important to state again that lepto in the UK is VERY rare and in the U.K. it is NOT a notifiable disease therefore there are NO accurate numbers for cases or reactions. Furthermore, it is incredibly difficult to test for and is impossible on a vaccinated animal to know if they "caught" the disease or it came from the vaccine.

IF your vet states they have CONFIRMED cases of lepto it’s important to ask them what serovar and if the animal was vaccinated or not. I would also encourage you to know and understand how the disease is transmitted as well as the signs and symptoms of leptospirosis. When symptoms do occur they usually appear between 4 and 12 days after exposure to the bacteria, and can include; fever, muscle pain, vomiting and diarrhoea, loss of appetite, lethargy, depression, and blood in the urine. You can find out more about these signs and symptoms here.