Questions about vaccine products

1. Are Toxoplasma vaccines available in other countries?

There are no commercial Toxoplasma vaccines available for use in cats anywhere in the world.

2. Canine coronavirus infection is quite common in our area. We often get positive reactions with commercial test kits for coronavirus. What does the VGG think of the use of coronavirus vaccine?

The VGG does not recommend the use of canine coronavirus vaccines as there is insufficient evidence that this vaccine is protective, or indeed that enteric coronavirus is a significant canine pathogen. Variant strains of this virus have been reported to cause disease in adult dogs and puppies in various parts of the world, but it is unclear that the available vaccines protect against these variants. The identification of coronavirus with a test kit does not necessarily mean it is the cause of disease.

3. Is a monovalent vaccine better than a multi‐valent vaccine?

Vaccines with the fewest components possible enable practitioners to adhere to the WSAVA guidelines. Multi‐component core MLV vaccines (e.g. for CDV, CAV‐2 and CPV‐2) are ideal for delivery of core vaccinations, but it is best to have individual vaccines for non‐core antigens (e.g. Leptospira, canine infectious respiratory disease complex) so that these may be given only when risk–benefit analysis suggests that they will be of benefit. For Leptospira vaccines, multi‐component products may provide the best protection if their formulation is based on scientific evidence that justifies the inclusion of multiple serovars in the vaccine.

4. Will the number of different antigens in multi‐valent vaccines adversely affect the efficacy of the vaccine?

No. For a multi‐valent vaccine to be licensed, the manufacturer must prove that each component of the vaccine can induce protective immunity, generally in challenge studies.

5. Can you give all vaccinations at once to an adult dog presented with no previous history of vaccination?

This is a similar question to that above. Yes, a dog should be able to respond to multiple antigens delivered simultaneously. However, you should never mix different vaccines in the same syringe unless specifically indicated by the datasheet. From first principles, it would be good practice to deliver the different vaccines to different anatomical sites so that different lymph nodes are involved in generating the adaptive immune response, but no studies have formally proven this.

6. What are the quality differences between MLV vaccines and “genetic” vaccines?

Genetic vaccines include virus vectored vaccines, genetically mutated (gene deleted) vaccines and naked DNA vaccines. These vaccines may theoretically be safer than certain MLV vaccines as there is no chance of “reversion to virulence”. These vaccines are also designed to produce an optimum immune response.

7. Can killed vaccines “break through” MDA better than live?

There is little evidence for this, but what is known is that some of the newer genetic vaccines appear to be able to generate immunity in the presence of MDA earlier than traditional MLV vaccines.

8. Small breeds of dogs commonly suffer from adverse reactions. Is it possible to reduce the dose of vaccine to avoid this?

No. Vaccine doses are not calculated on a milligram per kilogram basis, as are drugs. The entire antigenic load is needed to stimulate immunity effectively. You should not split vaccine doses, nor give reduced volumes to small dogs. In the USA, a new product has been released that is designed for small dogs. This is formulated as a 0 · 5 mL dose, but contains much the same amount of antigen as does a conventional 1 · 0 mL vaccine.

9. Why don't we have suitable combinations of core vaccines available to allow them to be used in accordance with the guidelines?

Suitable products are available in some other countries. If you do not have them, then you and your national small animal veterinary association should lobby the manufacturers and government regulators to bring the suitable products to your marketplace. In many cases, industry would like to make new products available, but the block lies with the licensing authority.

10. Why do we not have 3‐year DOI rabies vaccines?

As above, this may be because the manufacturers have chosen not to bring you these products or because the licensing authority has not permitted their introduction of a 3‐year labelling. In at least one Asian country, the only permitted rabies vaccine is a nationally produced product that only has a 1‐year licensed DOI.

11. Do canine core vaccines in Asia have a DOI of at least 7 years as stated by Dr Schultz?

Many internationally marketed MLV vaccines that are quality assured have been independently tested by Dr Schultz, and shown to be protective, in a challenge study at 7 to 9 years (Schultz et al. 2010, Journal of Comparative Pathology, 142, S102–S108). The VGG does not know which of the nationally produced core vaccines may have similarly long DOI.

12. A local 3‐way Leptospira vaccine is available in my country alongside the traditional bivalent products. Which one should I use?

If the local 3‐way vaccine contains a combination of “relevant” Leptospira serovars that usefully extends the breadth of protection provided by vaccination under your local conditions, then it is likely to be more effective and preferable to a traditional bivalent product.

13. Currently there are no Bordetella vaccines available in Japan. Do the VGG think Bordetella vaccines are important in Japan?

Vaccines against Bordetella bronchiseptica are non‐core products. Bordetella is just one of numerous pathogens that can be involved in causing upper respiratory tract disease in dogs and cats. Bordetella bronchiseptica has been shown to be an important cause of canine respiratory disease in Japan, as in other countries, along with canine parainfluenza virus (Mochizuki et al. 2008, Journal of Veterinary Medical Science, 70, 563–569). Yes, the VGG suggests that vaccines against canine infectious respiratory disease could be very useful to Japanese practitioners and should be introduced.

14. Some trivalent cat vaccines contain inactivated FPV and live FCV/FHV, can these still be used every 3 years?

Yes, this is a core vaccine. Inactivated FPV will still provide protection for a minimum of 3 years.

15. Is it better to use vaccines containing local strains rather than international vaccines?

There is no evidence that international core vaccines are unable to provide good protection against CDV, CAV‐1, CAV‐2, CPV‐2, FPV, FHV‐1 and rabies virus, worldwide. In most instances, strain variation does not change the key protective antigens of the organism that are conserved between strains. In the case of Leptospira, inclusion of additional, locally important serovars or strains in a vaccine may lead to enhanced protection.

16. A recent CPV outbreak in army dogs was shown to be caused by CPV‐2c. There are recommendations that vaccines should contain the latest strains, what's the VGG view on this?

Currently available international MLV vaccines contain CPV‐2 (original strain), CPV‐2a or CPV‐2b. These vaccines are expected to confer substantial cross‐protection against CPV‐2c challenge, and indeed some have been shown to do so, shortly after vaccination. At present, there does not seem to be a pressing need to change the formulation of canine parvovirus vaccines.

17. How do practices know that vaccines delivered to them have been stored correctly and that they are still potent? Can vaccines be delivered with indicators to assure correct storage?

We have asked this question to the manufacturers and suppliers of international vaccines during our Asian meetings and have been assured that there is continuation of the cold chain from importation to practice delivery. International manufacturers do utilise temperature indication systems during the bulk delivery stages.

18. There is no national policy in India giving advice and recommendations on canine vaccination. When will we get a local policy?

The WSAVA encourages all national small animal veterinary associations to develop national vaccination advice. This has already happened in many other countries. Some simply adopt and refer to the WSAVA guidelines, whereas others adapt the guidelines for the local situation. You should continue to lobby your national association to provide local guidance.

19. How common is tetanus in dogs? Should we vaccinate against it?

In many parts of the world, tetanus is uncommon in dogs. There are no licensed vaccines for dogs, but in some areas deemed as being at high risk, veterinarians do use equine tetanus vaccine in dogs (off‐label use). Given that tetanus is nowadays considerably more frequently observed than canine infectious hepatitis and canine distemper in many parts of the world, development of a canine tetanus vaccine may be justifiable and commercially viable.

20. Does the VGG recommend which vaccine brand should be used?

No. The VGG is an independent academic group that does not make product‐specific recommendations. However, in the case of international vaccines, the VGG knows that all of these products have undergone rigorous assessment of quality, safety and efficacy that has permitted their licensing in many countries. The VGG does not recommend the use of some vaccines – but this is based on a lack of adequate scientific evidence (i.e. peer‐reviewed scientific literature) that the vaccine is necessary or efficacious. Recommendations are reviewed and adjusted as needed periodically.

21. If one wants to use just the DHPPi without the Leptospira component of a vaccine, what should be used to reconstitute the DHPPi?

You should ask this question to the manufacturer or supplier of the particular vaccine, but a suitable diluent may be sterile normal saline or sterile water for injection. If not, the manufacturer should be able to provide you with the specific diluent required.

22. What about the use of rabies vaccine in small mammals (e.g. rabbits and guinea pigs)?

The VGG does not recommend rabies vaccination of these small mammals, except for ferrets.

23. Should Leptospira vaccine be used 6‐monthly in high‐risk areas?

Yes, this is consistent with the VGG recommendations in the WSAVA guidelines. You should ideally have a good scientific evidence base for stating that your practice is in a high‐risk area.

24. What happens if a dog is bitten by a free‐roaming dog after receiving the initial puppy rabies vaccine; should it receive PEP? What if that dog receives PEP and is then bitten again some weeks later, should it receive another course of PEP?

If the bitten puppy has been vaccinated properly, it should be protected against rabies. The VGG is aware that in India, PEP is used in this situation for the benefit of the puppy, and more importantly for the benefit of the human family. Repeated PEP is not justified. By that time the puppy will have received multiple vaccinations and further injections will provide no added benefit.

Questions about vaccine delivery to puppies and kittens

25. Is it OK to mix different manufacturer's products during the primary course?

Core MLV vaccines from the different international suppliers are similar in composition and may be mixed during the primary course (e.g. if a puppy has an 8‐ to 9‐week vaccine from one veterinarian and then moves to another veterinarian who uses a different product range). Manufacturers will not support this practice (and will advise against it) because they have not undertaken studies to prove compatibility of their products with those of other manufacturers. It may also be acceptable to use non‐core vaccines from different manufacturers, with the exception of Leptospira vaccines where a first dose with a two‐serovar product, and a second dose with a four‐serovar product, would not induce immunity to the additional two serovars contained in the four‐way vaccine.

26. In a puppy that has received inoculations at 6 and 9 weeks with one vaccine brand, and is then presented to a practice that uses another vaccine brand at 6 months, what should be given?

The second practice may give the international MLV core vaccine that they use routinely as described in the question above. If that puppy had not yet received a rabies vaccine, that should be given at 6 months as well (in a rabies endemic area). Remember that for puppies, some will not have responded to primary vaccination at either 6 or 9 weeks of age, and the VGG recommends a third vaccination at 16 weeks of age or greater.

27. Often puppies or kittens are groomed before vaccination – is this OK?

As long as the puppy or kitten is in good health and not overly stressed by the grooming procedure, there is no reason not to vaccinate after grooming.

28. Can you give rabies and DHPPi vaccine at the same time (concurrently)?

Yes, but unless the vaccines have a specific concurrent use claim on the product label, then this may be considered “off‐label” use. Ideally, the two vaccines used concurrently in this way should be given at different anatomical sites in order that vaccine antigens are carried to different lymph nodes in order to stimulate adaptive immunity at two distinct locations.

29. Can one use rabies vaccine 1 week after DHPPi?

Yes, there is no problem in doing that. As discussed earlier, it would be sensible to inject this into a different location in order to stimulate immunity via a different lymph node.

30. If a puppy suckles for more than 1 · 5 months, do you need to start the vaccination protocol later?

No. Remember that maternally derived antibody that interferes with puppy vaccination is only obtained from colostrum taken in during the first 24 to 48 hours of life. After that, entire antibody is not absorbed from the gastrointestinal tract.

31. Why don't the VGG recommend Rabies vaccination until after 12 weeks of age?

This recommendation is consistent with the datasheets for the majority of international vaccines.

32. Can we vaccinate puppies at less than 6 weeks of age?

In general, no. Puppies at this age will have MDA that blocks the ability of MLV vaccines to prime the immune system. Moreover, vaccine datasheets do not support this practice and there may be safety issues with giving MLV vaccine to very young animals (i.e. <4 weeks of age). One exception is the use of intranasal vaccines against canine infectious respiratory disease. These can be used safely from a very young age. Check product datasheets.

33. There are some nationally manufactured rabies vaccines that are combined with DHPPi. Manufacturers recommend that these can be given from 8 weeks of age. How come these vaccine datasheets can say this?

A datasheet recommendation should be based on proven safety and efficacy studies performed to the requirements of the licensing authority. One can only assume that such studies have been done and support this recommendation. If in doubt, inquire with the manufacturer or government authorities.

34. We have a core vaccine for puppies for which a final dose at 10 weeks is recommended. This seems contrary to the WSAVA guidelines.

Such “early finish” vaccines were introduced in order to encourage the early socialisation of puppies, which is very important for their development. We believe that 25% of the puppies still have blocking levels of MDA (particularly against parvovirus) at 10 weeks of age (and 10% at 12 weeks of age) and so there is a risk that not all puppies will be fully protected until they receive a 12‐month booster vaccine. The VGG recommends a final dose of puppy vaccine at 16 weeks of age or older.

35. The 2010 WSAVA guidelines advise a 14‐ to 16‐week final dose, but should this be 14, 15 or 16 weeks?

We would recommend the final dose to be given at the 16‐week end of this range and in the current document, we have used the phrase “at 16 weeks of age or older”. For kittens, there are new studies that show persistence of MDA even beyond 16 weeks, and when we next revise the global WSAVA guidelines, we will consider this new evidence for kittens.

36. In Thailand, the legal requirement is that puppies be vaccinated against rabies at 2 months of age – is this correct immunologically?

Most international canine rabies vaccines carry the recommendation for administration at 12 weeks of age, based on safety and efficacy studies. In this instance, the legal requirement would be in conflict with the datasheet recommendations if international vaccines are being used. Note that the WSAVA guidelines recommend a second vaccine be given (2 to 4 weeks later) in areas of high risk for rabies.

37. If the pup has no MDA, when should you start vaccination?

In a practical setting, it would be difficult to prove that a pup had no MDA. This would necessitate knowing definitively that the pup did not take in colostrum. However, if this was known, then core vaccination may be given from 6 weeks of age. Certain MLV vaccines must not be given any earlier than 4 weeks of age as they may cause pathology in the pup. If this pup definitively had no MDA, it may respond adequately to a single dose of vaccine at 6 weeks of age; however, it may be pragmatic to give a second dose at 16 weeks of age.

38. When can puppies go outside for proper socialisation?

There is no doubt that ensuring early socialisation is an important part of responsible puppy ownership. Owners should be made aware of the risks – that not every puppy will be fully protected against lethal (core) diseases until after the 16‐week vaccination (see Question 34). Owners should be advised about simple precautions; for example, only attending “puppy parties” where all of the dogs are vaccinated and attending such events on “clean territory” (e.g. not in the back room of the veterinary hospital).

39. If the puppy sneezes after intranasal vaccination, is it necessary to vaccinate again?

Sneezing, with loss of some of the vaccine, is commonly observed after the use of intranasal products. These vaccines have been designed to allow for partial loss of the product and so it should not be necessary to revaccinate, unless it is clear that none or very little of the product was delivered successfully.

40. What do we do if the animal is presented late for vaccination?

If this is a puppy, presented (for example) after 16 weeks of age, a single dose of international MLV core vaccine (CDV, CAV‐2 and CPV‐2) will be protective as will a single dose of rabies vaccine. Considering non‐core vaccines, it is necessary to give two doses 2 to 4 weeks apart. If this is an adult dog, presented for revaccination (for example) at 4 years rather than 3 years since its last core vaccination, the same would apply for core vaccines and canine rabies. Any adult dog that does not receive annual Leptospira vaccination should be treated as a puppy and receive two injections 2 to 4 weeks apart and then an annual vaccine.

Questions about vaccine delivery to adult animals

41. Do you need to continue to vaccinate old dogs?

For MLV core vaccines (CDV, CAV‐2, CPV‐2), current international recommendations are for revaccination of adult dogs no more frequently than every 3 years. Canine rabies vaccines should be given every 3 years where an international product is used (with a 3‐year DOI) and that is consistent with local legal requirements. If non‐core vaccines are chosen for use in an individual dog, they must be given at least annually.

42. At what age can one stop vaccinating dogs?

For core vaccines, the current recommendation is for lifelong revaccination no more frequently than every 3 years and if non‐core vaccines are chosen for use, these are generally given annually. One can use serological testing in any adult dog to confirm protection and elect not to revaccinate that animal. Current advice is that serological assessment is performed every 3 years, but in dogs older than 10 years, this should be done annually. In many Asian countries, there is also a legal requirement to vaccinate (currently annually) against rabies.

43. For an adult dog with no CDV antibody, what's the recommended vaccination protocol?

An adult dog requires only one dose of international MLV core vaccine to generate a protective immune response. We would recommend vaccinating the dog and testing serologically 4 weeks later. An estimated 1 in every 5000 dogs may be a genetic non‐responder to CDV and may never be able to respond to vaccination.

44. What protocol is recommended for an unvaccinated adult dog?

Core vaccination with a single dose of international MLV vaccine (CDV, CAV‐2, CPV‐2) plus rabies in endemic areas. Revaccination (or serological testing for CDV, CAV and CPV‐2) no more frequently than every 3 years thereafter. Non‐core vaccines should be selected based on a risk–benefit analysis for that individual animal.

45. For an adult dog with an unknown Leptospira vaccination history, what's the recommended vaccination protocol? Is it still two doses 4 weeks apart as in puppies?

Yes, this dog would require two doses of vaccine given 2 to 4 weeks apart and then annual revaccination thereafter.

46. How is it best to vaccinate a pregnant bitch? Is it best to give a booster vaccination before the pregnancy?

Vaccines should not be given during pregnancy unless specifically indicated in the datasheet. The best approach is to ensure that breeding bitches are vaccinated (with core vaccines), but it is unnecessary to give additional core vaccines to breeding bitches immediately before pregnancy – their standard vaccination schedule (e.g. triennial core revaccination) will provide adequate protective immunity and colostral antibody for the puppies.

47. If rabies vaccine is given multiple times during a period (6 months), is this safe?

The international rabies vaccines are very safe, but there is no need to administer them to individual‐owned pet dogs more frequently than every 3 years. The VGG is aware that in some Asian countries, the vaccine is used in a postexposure prophylaxis (PEP) protocol when a pet dog is bitten by a free‐roaming dog. If the pet dog is vaccinated and already protected, this procedure should not be encouraged.

48. What protocol is recommended for an unvaccinated adult cat?

For an adult cat that has never been vaccinated, the VGG recommends core vaccination with two doses of international MLV vaccine (FPV, FCV, FHV‐1) plus one dose of rabies vaccine in endemic areas. Revaccination (or serological testing for FPV) no more frequently than every 3 years thereafter. Non‐core vaccines should be selected based on a risk–benefit analysis for that individual animal.

49. A bitch that was initially vaccinated as a pup, but has not received booster vaccination since then was presented by the owners before breeding. Should she be revaccinated?

Yes. The bitch should receive one dose of international MLV core vaccine (CDV, CAV‐2 and CPV‐2) and in an endemic area also canine rabies vaccine.

Questions about vaccine husbandry and general vaccination

50. Is it OK to swab the vaccination site with spirit before vaccinating?

No, alcohol or other disinfectant might inactivate modified live virus in core vaccines.

51. Can you vaccinate and dose with anthelmintic at the same time?

There is no reason not to do this.

52. Should FIV‐positive cats be vaccinated?

It is suggested that FIV‐positive cats may not be able to respond adequately to vaccination and may also be more susceptible to develop a vaccine‐induced disease following MLV vaccination. The vaccination requirements of an FIV‐positive cat should be considered carefully. Such animals would be best housed indoors away from other cats and not permitted outdoor access. If core vaccination is essential, then use of a killed rather than MLV core vaccine is recommended.

53. Should a cat be vaccinated if it already has signs of upper respiratory disease?

A cat with current clinical disease should not be vaccinated. Once it has recovered, the cat should have some natural immunity to FCV or FHV (or both if both agents were involved in causing the respiratory disease), but such immunity is never sterilising (even after vaccination). There is no indication NOT to vaccinate a cat that has recovered from a respiratory viral infection. A trivalent vaccine will protect against FPV and also against the respiratory virus (FHV‐1 or FCV) that was not involved in causing the earlier respiratory disease.

54. Should you vaccinate E. canis‐infected dogs since these dogs can be immunosuppressed?

There is no evidence that a dog with monocytic ehrlichiosis cannot respond adequately to vaccination or that protective antibody titres against core vaccine components diminish in E. canis‐infected dogs. Ideally, the dog would be treated and any essential vaccination performed after the cessation of therapy. It may be a legal requirement to give rabies vaccine to such cases in any event.

55. Should one vaccinate an animal that is diseased or stressed?

No. This is contrary to good practice and the advice on most vaccine datasheets.

56. How should dogs on medication for immune‐mediated disease be vaccinated?

Antineoplastic drugs, and some of the most potent drugs used to treat immune‐mediated diseases, interfere with a dog's ability to respond immunologically to vaccination, but standard immunosuppressive doses of glucocorticoid have relatively little effect. Nevertheless, vaccines should not be administered to animals with significant disease and animals receiving high doses of glucocorticoid for immune‐mediated disease fall into this category. Vaccination should be delayed until after the drugs have been tapered or stopped. Most dogs receiving such therapy will be adult animals that will already have acquired long‐term immunological memory to core vaccine antigens and should be on a revaccination schedule of not more often than every 3 years for these core vaccines.

57. Does vaccination at different subcutaneous sites have the same efficacy?

This is an interesting question that has come about due to recommendations to vaccinate cats in locations other than the scruff of the neck in order to avoid the occurrence of a surgically challenging feline injection site sarcoma. In the USA, recommendations for vaccination of cats in the distal hindlimbs are made. The WSAVA vaccination guidelines propose vaccination into the skin of the lateral abdomen. In a recent pilot study, investigators vaccinated cats into the distal tail and actually addressed the question of efficacy by showing that such cats made protective serological responses to FPV and rabies virus (Hendricks et al. 2014, Journal of Feline Medicine and Surgery, 16, 275–280). It has been suggested that further work is needed to ensure injection of heavily adjuvanted vaccines into the tails of cats is safe: it is feared that swelling in such a tight area may lead to development of “compartment syndrome” in some cats. However, this was not noted in the pilot study.

58. Power cuts are not uncommon in parts of our country and they can last for 2 to 3 days. What should one do as regards any vaccine in the fridge at the time – is it OK to use?

MLV vaccine that has not been stored at appropriate temperature for 2 to 3 days should not be used. Some of the components of these vaccines (e.g. CDV) are temperature sensitive and there may have been inactivation of the virus.

Questions about the use of serological testing

59. How long after CPV‐2/CDV vaccination should you wait before measuring protective antibody concentrations using in‐clinic tests?

This question is most relevant for puppies, because adult dogs are likely already to have serum antibodies present at the time of booster vaccination, regardless of how long an interval there has been since they were last vaccinated. If a puppy receives its final primary vaccine at 16 weeks of age, then it may be tested from 20 weeks of age onwards. Any antibody present at that stage cannot be of passive, maternal origin and therefore indicates that the puppy is actively protected.

60. Why don't the VGG recommend that you do a rabies antibody test?

For many Asian veterinarians, this question may be of little practical consequence, as regular rabies vaccination of dogs and cats is a legal requirement in many countries, irrespective of any titre results. Rabies antibody testing is only required in certain situations related to international pet travel. The international rabies vaccines are highly efficacious and it is generally considered that there is no need to demonstrate immunity post vaccination.

61. Can we use antibody tests (CDV, CPV‐2 and CAV) to test the MDA in order to decide the first vaccination time?

Theoretically, this would be possible and years ago a “nomogram” was often used to estimate when pups might best respond to vaccination on the basis of the titre of antibody in the serum of the bitch. In practice, it would be very difficult and expensive to repeatedly sample and test young puppies in order to monitor the decline of MDA.

62. What happens to the antibody titre over the 3‐year period post vaccination?

For CDV, CAV‐2, CPV‐2 and FPV, the antibody titre will be consistently present at similar titre. This has been shown in numerous field serological surveys of dogs last vaccinated up to 9 years previously and in experimental studies for dogs last vaccinated up to 14 years previously. For Leptospira, the titres will decline rapidly after vaccination and in any case are not well correlated with protection. Serum antibody titres are less relevant for FCV and FHV‐1 where the most important type of immunity is mucosal and cell‐mediated, respectively.

63. In an animal that has completed its puppy/kitten shots, is a higher antibody titre required to protect against heavy disease challenge?

For CDV, CAV‐2, CPV‐2 and FPV, the answer is no. The presence of antibody (no matter what the titre) indicates that protective immunity and immunological memory is present in that animal. Giving more frequent vaccines to animals in an attempt to increase antibody titre is a pointless exercise. It is impossible to create “greater immunity” by attempting to increase an antibody titre.

64. Can we test dogs as an alternative to annual vaccination? We are concerned about the advice to only boost every 3 years.

Yes, certainly. There are now well‐validated in‐practice serological test kits that permit determination of the presence of protective serum antibody specific for CDV, CAV, CPV‐2 and FPV. In other countries, these kits are used to confirm protection at 3‐year intervals (instead of automatic revaccination for core diseases). You may perform serology annually, but if you collect and analyse the data that you generate within your practice, you will soon find that annual testing is not necessary.

Questions about the annual health check

65. In the annual health check, what tests/examinations should you do?

The annual health check should focus on the basic physical examination (including body temperature, cardiac auscultation and palpation). An excellent history should be taken to understand the lifestyle and disease risks (e.g. travel, boarding, indoor versus outdoor exposure). The fundamentals of nutrition and parasite control should be discussed with the owners.

66. Some owners may be reluctant to come back just for an annual health check. What advice can be provided to promote the health check concept in order to improve owner compliance?

This is all a matter of education. Clients should realise that the health check examines all aspects of the health and wellbeing of their pet and may pick up the early stages of clinical problems. In terms of vaccination, the health check examination might include serology (every 3 years for core vaccine antigens) or the annual administration of non‐core vaccine if such vaccines are required.

67. The costs of an annual health check are far too high for my clients.

The annual health check may be as simple as an excellent clinical history and physical examination – the costs for which are purely the professional time of the veterinarian. Fundamentally, the concept of an “annual health check” is a new way of delivering what most practitioners already offer as a “vaccination booster and physical examination”. For more affluent clientele, the annual health check has proven a means of offering other veterinary services and increasing practice profitability. This is also an example of practicing better quality medicine and about redefining the veterinarian–client relationship.

Questions about vaccine adverse effects

68. In case of a mild allergic reaction to a vaccine, can you use steroids to treat?

Yes; reactions such as facial oedema and pruritus may be treated with anti‐inflammatory (not immunosuppressive) doses of oral glucocorticoid (e.g. prednisolone) and/or with antihistamines.

69. If an animal suffers an allergic reaction post vaccination, what should you do when the next vaccination is due?

In this situation, there is a risk that revaccination will trigger the same allergic reaction. The answer to the question depends on the age of the dog and the stage of the vaccination programme, and the type of vaccine under consideration. For core vaccines, it is important that the animal receives one dose at 16 weeks or greater to induce protective immunity. An antihistamine or an anti‐inflammatory dose of glucocorticoid may be administered to such animals in advance of vaccination, and they should be closely monitored immediately afterwards. Thereafter, such an animal might be serologically tested to demonstrate protective immunity rather than automatically revaccinated. If the reaction occurred in an adult dog, serological testing may be used instead of core revaccination. If the reaction is thought to have been triggered by a non‐core vaccine, consideration should be given as to whether the animal really requires that vaccine in the future.

70. Is there evidence that cutaneous vasculitis can be caused by vaccination?

Yes, this is a very rare, but recognised, adverse reaction following vaccination, particularly rabies vaccination.

71. What are adverse hypersensitivity reactions and how can these be differentiated clinically?

The most common such reactions are facial oedema and cutaneous pruritus occurring within an hour (generally less) of vaccination. The temporal relationship suggests that the vaccine has triggered the reaction.

72. Do we see signs of cutaneous allergic reactions in cats as in dogs?

Yes. Cats may present with the same manifestations of type I hypersensitivity post vaccination as dogs (e.g. facial oedema and cutaneous pruritus).

73. How do we know that a feline sarcoma was caused by a vaccine? How do we deal with this type of sarcoma?

A feline injection site sarcoma (FISS) arises at an anatomical location into which injectable product has been delivered previously. It is suspected that a wide range of injectables, including vaccines, may potentially trigger these tumours. It is important to record the site of vaccination in cats in the medial record of the animal and the WSAVA guidelines give advice on suggested best locations for vaccinating cats. Unfortunately, these sarcomas are very aggressive. They infiltrate widely and around 20% may metastasise. They require significant surgical resection that is often best performed by a specialist.

74. Why are there more hypersensitivity cases caused by rabies vaccine than before? Why is this more common among toy poodle dogs?

Hypersensitivity reactions may be caused by any type of vaccine, but killed adjuvanted products may be particularly associated with this type of reaction. We now know that a dominant antigen that causes these reactions is bovine serum albumin (BSA) that is incorporated into vaccines during their production. Manufacturers are now trying to reduce the concentration of BSA in animal vaccines. Such reactions are more common in many toy breeds, and in many countries, these breeds are now particularly popular. There is likely to be a genetic susceptibility, but this is poorly understood.

75. Why do some dog breeding kennels continually have problems with dogs dying from CDV and CPV‐2 infections?

The most likely cause for this scenario is that the breeding stock is not adequately vaccinated. Outbreaks might occur among puppies that did not obtain sufficient MDA as the bitch was not effectively vaccinated. In contrast, where puppy vaccination is not performed according to WSAVA guidelines (i.e. with a final puppy vaccine at 16 weeks of age or older), there is a risk that some puppies may be unprotected if the bitch does have a high level of MDA. Finally, there are some breeds of dog (e.g. Rottweiler, Dobermann) that have a greater risk of being genetic non‐responders to these vaccines. Good husbandry, hygiene and nutrition all play a role in minimising disease outbreaks in kennels.

76. Can a modified live virus revert to virulence? Will a dog be infected by an MLV vaccine?

Yes, an MLV vaccine strain can theoretically revert to virulence, but this is exceedingly rare. Yes, MLV vaccines are called “infectious vaccines” because they work by inducing a low level of infection (and virus replication) in the dog, sufficient to induce immunity, but not disease. In the case of canine parvovirus, vaccinated dogs might shed the MLV vaccine strain of virus in the faeces for a short period after vaccination. This does not pose a risk to other dogs.

77. Some pups were vaccinated at 6 weeks of age with DHPPi and went down with infectious hepatitis at 7 weeks of age; why did this happen?

The most common reason for this occurrence (i.e. infection in a vaccinated pup) is that the animal was already incubating infectious virus before it was vaccinated. It is possible that these pups might have been infected during the “window of susceptibility” when they no longer had sufficient MDA to fully protect them against virulent street virus, but the MDA that was present was still sufficient to interfere with their immune response to a recently administered vaccine.

78. Apart from the (very small) risk of adverse reaction, what are the other risks of annual vaccination?

The risks of adverse reaction following vaccination are indeed relatively small. For dogs and cats, this is in the order of 30 to 50 reactions for every 10,000 animals vaccinated, respectively, and the vast majority of these are non‐serious reactions (e.g. transient pyrexia and lethargy, allergic reactions). However, if a serious reaction occurs in one of your client's animals – that is a difficult discussion to have. Adoption of new guidelines is not simply about minimising the risk of adverse reactions – it is about practicing better, evidence‐based veterinary medicine and only performing a medical procedure (i.e. vaccination) when this is required.

79. Some dogs are genetically poor responders (e.g. Rottweilers). How should one vaccinate these breeds?

The WSAVA guidelines contain a useful flow diagram that helps you identify non‐responder dogs. All puppies should be vaccinated in the same way (with a final vaccination at 16 weeks of age or older) and if you are concerned about the breed and the potential for lack of response, you should serologically test at 20 weeks of age. Most non‐responders will fail to seroconvert to just one of the core vaccine antigens (i.e. CDV, CAV or CPV‐2). You may attempt to revaccinate and retest that dog, but a true non‐responder (or low‐responder) may still not respond to revaccination. Such animals simply lack the immunological ability to make an immune response to that particular antigen and will never respond to that vaccine component. Owners should be made aware that these dogs will be at risk, and ideally, they should not be used for breeding.

80. How should we analyse the risk–benefit of vaccinations?

Risk–benefit analysis really only applies to the choice of non‐core vaccines, as it is taken as given that all dogs and cats (no matter where or how they live) should receive core vaccines (including rabies in endemic areas). The risk–benefit analysis is made for the individual animal, taking into consideration what the owner has told you about its housing, indoor–outdoor access, travel and boarding frequency, exposure to other animals (e.g. part of a multi‐pet household) etc. The risks to consider are (1) the risk of adverse reaction following vaccination, (2) the risk that you will be performing an unnecessary medical procedure, (3) the risk that the animal will become infected with the infectious agent based on scientific knowledge about the prevalence of disease in your area, and (4) the risk of developing clinical disease following that infection. The possible benefits to consider are (1) whether the vaccine might protect the animal from infection if its lifestyle or geographical location means it is likely to be exposed to that infectious agent, (2) whether the vaccine might reduce the severity of clinical signs should that animal become infected, and (3) whether the animal being vaccinated contributes to herd immunity among the population.