Article Text


Decision making
Repeat vaccinations
  1. David Williams


An owner presents her one-year-old dog for its repeat vaccinations. She is a lecturer in immunology at the local university and asks you why her dog needs to be vaccinated again. The whole idea of an immune response is that it has a long-lasting memory, she says. As an example, she points out that children do not need to be vaccinated yearly against measles, mumps or rubella. She suggests that yearly vaccinations are only recommended to provide veterinary surgeons with a regular income stream and that she considers this to be unethical. How should you respond?

Statistics from

David Williams teaches veterinary ophthalmology at Cambridge Veterinary School and is director of studies in veterinary medicine at St John's College, Cambridge. He is also involved in animal ethics and welfare teaching and research at both undergraduate and postgraduate levels.

Issues to consider

Concerns about the necessity of yearly vaccinations and the potential for adverse effects are raised frequently by clients. The owner is correct in that vaccination centres around the concept that vaccinating against a particular pathogen will incite long-term immunity against that pathogen. However, the issue is complicated by differences between pathogens, vaccines and the prevalence of the pathogen in the recipient population. Roth and Spickler (2010) provided a useful review on the duration of immunity induced by vaccines currently used in small animal veterinary practice. The duration of immunity is considerably shorter after vaccination than after recovery from the disease itself. Given that most of the companion animal diseases that are being vaccinated against are no longer circulating within the pet population, there are no natural boosters of immunity. Roth and Spickler (2010) discuss studies that suggest that immunity persists for several years after vaccination and that dogs with non-protective titres may have memory B cells. This is certainly true for distemper and canine parvovirus. However, as one such study notes, ‘it is not proven that dogs with fourfold increases in titres are necessarily protected from challenge’. It is the lack of complete confidence, one might suppose, that leads many practices to recommend yearly vaccination, even for diseases such as distemper and canine parvovirus for which the duration of immunity is most probably considerably longer.

Are the side effects of vaccination outweighed by the benefits? A number of adverse reactions to vaccination have been recognised, from regional lymphadenopathy to transient systemic non-specific illness (Day 2006). The possible link to autoimmune diseases such as immune-mediated haemolytic anaemia, thrombocytopenia, polyneuritis and arthritis is of more concern, but has only anecdotal data to support it. The incidence of feline vaccine-associated sarcoma has a stronger scientific basis, but, given that the prevalence is low (one or two per 10,000 vaccinations), the benefit of vaccination far outweighs the risk. Similar lesions have been reported in dogs and ferrets, but at even lower prevalences. Given the severity of signs in diseases such as parvoviral diarrhoea and leptospirosis, the owner can be reassured that the benefits of vaccination far outweigh the risks.

What of this owner's concern that veterinary practices are using yearly vaccination as a valuable and, to her mind, unethical method of income generation? Two issues might present themselves here.

The first is positive. A yearly vaccination encourages owners to present their pet for a yearly examination. If a thorough routine clinical examination is provided at the same time as vaccination, conditions are more likely to be diagnosed early in their development. If left until the signs are obvious to the owner, the same condition – be it a neoplastic mass or anaemia – might be substantially more serious.

A second issue concerns the financial gain to the veterinary practice from yearly vaccination. It cannot be denied that the prices charged for vaccinations are considerably higher than the cost to the practice of the vaccine itself. In some practices, such an income stream may subsidise other services, such as complex surgeries, that are not charged as highly as they could be. This is now less common than it has been in the past, in part due to recent legislation that encourages the transparency of pricing, but is it ethical to overcharge some owners to make it possible to reduce the fees for other cases? Principlism is a system of ethics based on four moral principles: autonomy, beneficence, non-maleficence and justice (Beaumont and Childress 2008). Autonomy indicates that individuals (in this case, clients) should be given sufficient information and freedom to make their own choices about treatment. Beneficence and non-maleficence require veterinary surgeons to maximise the benefits to their animal patients and minimise the harm done to them. Justice demands fairness to those animals treated and, presumably, to the owners who are paying for treatment. In this case, the principles demand that owners' autonomy should be promoted by them being given full, or perhaps we should say sufficient, information concerning treatment options for their animals including requirements for periods between vaccinations. Beneficence and non-maleficence require a cost–benefit analysis between delaying vaccination and vaccinating when not necessary. Justice requires, among other things, that owners are charged the correct amount for the treatment their pets require.

Possible way forward

As the Veterinary Defence Society regularly reminds us, the key feature of the vet–client relationship is communication, and that should certainly be the case here. Giving the client as much information as they require to guide their decision is vital. It is to be hoped that, together, the vet and the client can come to a rational and amicable decision about the vaccination protocol for the animal.

Any comments?

Readers with views to contribute on ‘Repeat vaccinations’ should e-mail them to inpractice{at} so that they can be considered for publication in the next issue, or fax comments to 020 7383 6418. The deadline for receipt of comments is Friday, April 20. Please limit contributions to 200 words.


THIS series gives readers the opportunity to consider and contribute to discussion of some of the ethical dilemmas that can arise in veterinary practice. Each month, a case scenario is presented, followed by discussion of some of the issues involved. In addition, a possible way forward is suggested; however, there is rarely a cut-and-dried answer in such cases, and readers may wish to suggest an alternative approach. This month's dilemma, ‘Repeat vaccinations’, is presented and discussed by David Williams. Readers with comments to contribute are invited to send them as soon as possible, so that they can be considered for publication in the next issue. Discussion of the dilemma ‘Genetic testing for coat colour in cats’, which was published in the March issue of In Practice, appears on page 247.

The series is being coordinated by Siobhan Mullan, of the University of Bristol. It is hoped it will provide a framework that will help practices find solutions when facing similar dilemmas.


View Abstract

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.