Does Your Dog Really Need an Annual Booster?

For many dog owners, the annual trip to the vet for a ‘booster shot’ is seen as routine and necessary. But as awareness around canine health grows, so do questions: What exactly is an annual booster? Does your dog really need one every year? And are there safer, smarter ways to protect your pet?

In this article, we will explore the facts, the science, and the natural support options available to help you make the most informed decision for your dog.

What is an ‘Annual Booster’?

The term ‘annual booster’ usually refers to a repeat yearly vaccination for core or non-core diseases. In Australia, these commonly include the C3 (core vaccines against parvovirus, distemper, and adenovirus) and additional non-core components, including parainfluenza virus and Bordetella bronchiseptica (both of which contribute to kennel cough), together referred to as the C5 vaccine.

Puppies receive a series of immunisations in their early months, typically followed by a booster at 6 months of age. After that, many vets recommend annual revaccination; but is that always necessary?

What the Science Says About Duration of Immunity

Research shows that the duration of immunity (DOI) for many core canine vaccines extends well beyond one year, often lasting three years or more. The World Small Animal Veterinary Association (WSAVA) Guidelines state: “Vaccines should not be given needlessly. Core vaccines should not be given any more frequently than necessary in adult animals.” WSAVA also notes that core vaccines can provide robust protection for many dogs without the need for annual boosting. In fact, over-vaccinating a dog that already has strong immunity offers no added benefit and may increase the risk of adverse reactions.

When to Be Cautious: Risks of Over-Vaccination

While vaccines are essential in preventing serious disease, repeated or unnecessary vaccinations can pose risks, particularly in sensitive individuals. Potential adverse effects may include:

• Allergic reactions (e.g. hives, facial swelling, generalised itching, anaphylaxis).
• Autoimmune responses.
• Non-specific signs (e.g. fever, fatigue, loss of appetite).
• Swelling, inflammation, or soreness around the injection-site.
• Injection-site sarcomas (rare but documented).
• Collapse (also rare but documented).

These concerns are especially relevant for dogs with a history of immune issues, allergies, or chronic illness. In such cases, a personalised vaccine schedule, rather than a one-size-fits-all approach, is often more appropriate.

Titre Testing: A Safer, Smarter Approach

So how do you know if your dog still has immunity? The answer lies in a simple blood test known as a titre test. This test measures the level of antibodies against specific diseases (e.g. parvovirus, distemper), giving a clear picture of your dog’s current immunity status.

If titres are strong, there may be no need to re-vaccinate at that time. Many holistic and integrative vets recommend titre testing every 3 years, or even longer, instead of annual boosters, particularly for low-risk dogs.

Supporting Immunity Naturally

Regardless of your vaccination schedule, there are powerful ways to naturally support your dog’s immune system and resilience:

• Bovine Colostrum: Colostrum is nature’s first food - the antibody-rich milk produced after birth. It contains immunoglobulins, growth factors, antimicrobial compounds, and enzymes that can help modulate the immune system, support gut lining integrity, and promote recovery after illness or vaccination. It can also improve a dog’s response to vaccination.
• Gut Support: A healthy gut is foundational to a strong immune system. In fact, 70–80% of immune tissue resides in the gut! For optimal gut lining integrity and microbial balance, healthy digestion, and enhanced immune function, look for these key ingredients:
  • Inulin (prebiotic from Jerusalem artichoke)
  • Psyllium husk
  • Larch arabinogalactan
  • Bacillus coagulans (LactoSpore® probiotic)
  • DigeZyme® (digestive enzymes)
  • Chamomile (Matricaria chamomilla) and Fennel (Foeniculum vulgare), herbs for soothing gastrointestinal support

In combination, these prebiotics, probiotics, herbs and enzymes help reduce the risk of post-vaccine digestive upset and encourage balanced immune responses.

• Organic Green Superfoods: Green superfoods are rich in antioxidants and are brilliant for enhancing immunity. Spirulina, in particular, a blue-green algae, is known for its immune-boosting and anti-inflammatory properties. Spirulina has been shown to stimulate antibody production and enhance the activity of natural killer cells. It also supports detoxification, which is particularly helpful when used around vaccination.
• Milk Thistle: Milk thistle (Silybum marianum) has long been used to support liver detoxification, especially when the liver is under stress from medications, toxins, or vaccine adjuvants. For dogs undergoing vaccination, it’s a gentle, evidence-backed way to support liver health and antioxidant defences. Many pet owners choose to use Milk Thistle for a week before and after vaccinations to assist the body's natural detox pathways.

The Takeaway

Vaccines save lives, but like all medical decisions, they should be tailored to your individual dog’s needs, health history, and risk exposure. An annual booster may not be necessary for every dog, especially if strong immunity is already present. Titre testing provides a safe, evidence-based way to assess protection and avoid unnecessary vaccination. With the right natural supports - such as bovine colostrum, gut and liver support, and antioxidant-rich superfoods - you can ensure your dog’s immune system is as robust, balanced, and resilient as possible.

References (click to expand)

Alves, J. C., Santos, A., Jorge, P., & Pitães, A. (2021). The use of soluble fibre for the management of chronic idiopathic large-bowel diarrhoea in police working dogs. BMC Veterinary Research, 17(1), 100. https://doi.org/10.1186/s12917-021-02809-w

Australian Veterinary Association. (2018, August 6). Vaccination of dogs and cats. Australian Veterinary Association. https://www.ava.com.au/policy-advocacy/policies/companion-animals-health/vaccination-of-dogs-and-cats/

Das, B., Rabalais, J., Kozan, P., Lu, T., Durali, N., Okamoto, K., ... & Sivagnanam, M. (2022). The effect of a fennel seed extract on the STAT signaling and intestinal barrier function. PloS One, 17(7), e0271045. https://doi.org/10.1371/journal.pone.0271045

Day, M. J. (2011). Vaccination of dogs and cats: no longer so controversial. Veterinary Record, 168(18), 480–482. https://doi.org/10.1136/vr.d2810

Day, M. J., Horzinek, M. C., Schultz, R. D., & Squires, R. A. (2016). WSAVA Guidelines for the vaccination of dogs and cats. The Journal of Small Animal Practice, 57(1), E1. https://doi.org/10.1111/jsap.2_12431

Fanoudi, S., Alavi, M. S., Karimi, G., & Hosseinzadeh, H. (2020). Milk thistle (Silybum marianum) as an antidote or a protective agent against natural or chemical toxicities: a review. Drug and Chemical Toxicology, 43(3), 240–254. https://doi.org/10.1080/01480545.2018.1485687

Grieshop, C. M., Flickinger, E. A., & Fahey Jr, G. C. (2002). Oral administration of arabinogalactan affects immune status and faecal microbial populations in dogs. The Journal of Nutrition, 132(3), 478–482. https://doi.org/10.1093/jn/132.3.478

Majeed, M., Nagabhushanam, K., Paulose, S., Arumugam, S., & Mundkur, L. (2023). The effects of Bacillus coagulans MTCC 5856 on functional gas and bloating in adults: A randomised, double-blind, placebo-controlled study. Medicine, 102(9), e33109. https://doi.org/10.1097/MD.0000000000033109

Majeed, M., Majeed, S., Nagabhushanam, K., Arumugam, S., Pande, A., Paschapur, M., & Ali, F. (2018). Evaluation of the safety and efficacy of a multienzyme complex in patients with functional dyspepsia: a randomised, double-blind, placebo-controlled study. Journal of Medicinal Food, 21(11), 1120–1128. https://doi.org/10.1089/jmf.2017.4172

Moore, G. E., Guptill, L. F., Ward, M. P., Glickman, N. W., Faunt, K. K., Lewis, H. B., & Glickman, L. T. (2005). Adverse events diagnosed within three days of vaccine administration in dogs. Journal of the American Veterinary Medical Association, 227(7), 1102–1108. https://doi.org/10.2460/javma.2005.227.1102

O‘G‘Li, F. J. S. (2022). Chamomile: A herbal medicine of the past with bright future. European International Journal of Multidisciplinary Research and Management Studies, 2(04), 251–254. https://doi.org/10.55640/eijmrms-02-04-47 Pinna, C., & Biagi, G. (2014). The utilisation of prebiotics and synbiotics in dogs. Italian Journal of Animal Science, 13(1), 3107. https://doi.org/10.4081/ijas.2014.3107

RSPCA Australia. (2025, April 30). What vaccinations should my dog receive? RSPCA Knowledgebase. https://kb.rspca.org.au/knowledge-base/what-vaccinations-should-my-dog-receive/#ftn1

Satyaraj, E., Reynolds, A., Pelker, R., Labuda, J., Zhang, P., & Sun, P. (2013). Supplementation of diets with bovine colostrum influences immune function in dogs. British Journal of Nutrition, 110(12), 2216–2221. https://doi.org/10.1017/S000711451300175X

Satyaraj, E., Reynolds, A., Engler, R., Labuda, J., & Sun, P. (2021). Supplementation of diets with spirulina influences immune and gut function in dogs. Frontiers in Nutrition, 8, 667072. https://doi.org/10.3389/fnut.2021.667072

Squires, R. A., Crawford, C., Marcondes, M., & Whitley, N. (2024). 2024 guidelines for the vaccination of dogs and cats – compiled by the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA). Journal of Small Animal Practice, 65(5), 277–316. https://doi.org/10.1111/jsap.13718

Wiertsema, S. P., van Bergenhenegouwen, J., Garssen, J., & Knippels, L. M. (2021). The interplay between the gut microbiome and the immune system in the context of infectious diseases throughout life and the role of nutrition in optimising treatment strategies. Nutrients, 13(3), 886. https://doi.org/10.3390/nu13030886