Over 50 years ago now, my friend and colleague, Prof. Ron Schultz, and I were the only two people saying we were over-vaccinating pets. I was called irresponsible in public at a large veterinary conference because others were unwilling to consider the idea that vaccines might not always be needed or safe. Since then, people aren’t shooting arrows at us now because our backs are full of them! Joking aside, despite the criticism, we were and remain determined to continue to educate about this topic.
Even today, estimates are that only about 40% of veterinarians are following the current WSAVA, AVMA, AAHA and BVA vaccine policy guidelines. * There is no such thing as an ‘up to date’ or ‘due’ vaccination. Enlightened veterinarians now can offer a package of separated vaccine components, when available, rather than give them all together, since the published data show more adverse reactions when multiple vaccines are administered at the same time.
Summary on Vaccine Policy
AAHA 2003 – Current knowledge supports the statement that
- No vaccine is always safe, no vaccine is always protective and no vaccine is always indicated
- Misunderstanding, misinformation and the conservative nature of our profession have largely slowed adoption of protocols advocating decreased frequency of vaccination
From Prof. Michael J. Day
- Vaccination should be just one part of a holistic preventive healthcare program for pets that is most simply delivered within the framework of an annual health check consultation
- Vaccination is an act of veterinary science that should be considered as individualized medicine, tailored for the needs of the individual pet, and delivered as one part of a preventive medicine program in an annual health check visit
Importantly, pet caregivers should understand that the act of giving a vaccine may not equate to immunization of that animal. Vaccines may not always produce the needed or desired immune protective response, not only if the vaccine itself was inadequately prepared (very rare) but also if the pet is a genetic low or non-responder to that vaccine (quite common in certain breeds of dogs and their families). In the latter case, that pet will be susceptible lifelong to the disease of concern and revaccination will not help and could even be harmful.
In response to issues raised above, vaccine experts recently have recommended new protocols for dogs and cats. These include: 1) giving the puppy or kitten vaccine series later (starting not before 8 weeks of age, except in the cases of outbreaks of virulent viral disease or in orphans or those that never received colostrum from their dams) followed by a booster at one year of age; 2) administering further boosters in a combination vaccine every three years or as split components alternating every other year until; 3) the pet reaches geriatric age, at which time booster vaccination is likely to be unnecessary and can be unsafe for those with aging-related or immunologic disorders.
In the intervening years between booster vaccinations, and in the case of geriatric pets, circulating humoral immunity can be evaluated by measuring serum vaccine antibody titers as an indication of the presence of immune memory (e.g. VacciCheck). Titers do not distinguish between immunity generated by vaccination and/or exposure to the disease, although the magnitude of immunity produced just by vaccination is usually lower.
When to Vaccinate Puppies & Kittens? Which Vaccines are Needed? What About Socialization?
- Should receive MLV or recombinant “Core” vaccines (canine distemper, parvovirus and hepatitis/adenovirus) preferably either at 9-10 and 14-16 weeks of age (minimum protocol), or, at 9, 12 and 16-18 weeks of age
- Rabies vaccines are all adjuvanted killed products and are given as required by law, preferably always given separately from other vaccines, and as late as legally allowed – e.g. 20-24 weeks of age. Thimerosal (mercury) - free rabies vaccines are preferred and safer
- Other vaccines are optional, and depend upon circumstances and disease risk in the area
- For the optional Bordetella or kennel cough vaccines, the oral version is preferred over the intranasal although both offer better protection than the injectable version
- Leptospirosis vaccines protect against only 4 serovars of the organism and are second to rabies vaccines in risk of hypersensitivity and other adverse effects. Use if endemic in the area of concern
- While canine influenza viruses (2 strains; H3N2 and H3N8) are highly contagious, most infected dogs have mild to no clinical issues, unless they develop a high fever and are at risk for secondary pneumonia. Vaccination, while being widely promoted, is still optional
- Three or more days after the last round of puppy vaccines, they can be out and about to be socialized. In the interim period, between 10-14 weeks of age, socialization can take place in the back yard or at puppy training classes with known friends and healthy dogs
- Until fully vaccinated, puppies should not walk on unfamiliar or public grounds; they can be carried about, when needed to travel
- If Titer testing is desired, instead of giving another vaccine after 12 weeks of age, wait until at least 16 weeks of age to avoid measuring residual maternal immunity
- Core vaccines (feline panleukopenia, feline calicivirus, feline rhinotracheitis/herpes) given as MLV or killed, inactivated or intranasal products are started in a 2 or three-dose series beginning for example at 7-9 weeks of age and 12-16 weeks, or at 7, 11 and 16 weeks
- Rabies vaccines if legally required are recommended as for puppies, although cats can receive a recombinant non-adjuvanted rabies vaccine which is preferred over the adjuvanted killed rabies vaccines given to dogs. This non-adjuvanted rabies vaccine is not yet available for dogs
- Some people consider feline leukemia virus (FeLV) vaccine as important for cats, especially those that live outdoors or are indoor/outdoor. Options are a recombinant non-adjuvanted or a killed adjuvanted vaccine
- Feline immune deficiency virus (FIV) vaccine is available in an adjuvanted killed virus vaccine for those cats at similar exposure risk to FeLV.
- Other vaccines (Chlamydia, FIP) are generally not recommended or are optional, and depend upon circumstances and disease risk in the area
- Socialization and Vaccine Titer testing options are as for puppies
*WSAVA-World Small Animal Veterinary Association; AVM A- American Veterinary Medical Association; AAHA-, American Animal Hospital Association; BVA- British Veterinary Association
Most puppies are vaccinated several times at 6, 9 and 12 weeks, as it is known that maternally derived antibodies can cause a vaccination to fail. However, is that sufficient? How do you know whether your dog is protected?
Pups are given, right after birth, via the first mother's milk, (colostrum) antibodies, that will protect against infectious and fatal diseases. These so-called maternally derived antibodies are temporary and disappear gradually, but can be present in the blood of the pups for up to 20 weeks or longer. If, however, the mother dog has no, or too few antibodies, the pups will not get them through the colostrum and are unprotected! It is important to protect puppies at the right time by means of a vaccination that stimulates the body to produce antibodies. This ensures permanent immunity.
The goal of a vaccination is to make dogs immune to certain diseases. However, it is a misconception to think that all animals, that have been vaccinated, are actually protected. A vaccination does not automatically lead to protection in young animals, that are still protected by maternally derived antibodies. In the Netherlands and Belgium, pups are usually vaccinated at 6, 9 and 12 weeks. The last vaccine of the puppy vaccination schedule will be administered around the age of 1 year, and then every 3 years they are vaccinated against infectious hepatitis, parvo and distemper.
Most pups are vaccinated several times, because it is known that maternally derived antibodies can block a vaccination. By administering a vaccine regularly every 3 weeks, there is a chance that one will catch. The problem lies in the fact that most puppies get their last vaccination at 12 weeks. As maternal immunity can last up to 20 weeks, and sometimes even longer, there is a big chance that they will walk around unprotected for up to 1 year, the age at which they receive the last vaccination of the vaccination schedule. People mistakenly think that their dog is optimally protected by this vaccination, but there is still at risk of contracting and spreading diseases. The dogs will then go unprotected to dog schools, boarding kennels, shows, competitions, animal events, dog parks and so on.
Optimal vaccination schedules
It would be much better, and more responsible, to adjust the current vaccination schedule according to the vaccination guidelines of the WSAVA. The WSAVA is a scientific committee, which sets out guidelines worldwide regarding the vaccinations of dogs and cats. In these guidelines, it is stated, that among other things, it is not wise to administer the last vaccination before the age of 16 weeks. There are two possibilities:
- A titer determination at 20 weeks. If the result is positive, the dog does not need to receive extra vaccination and the animal can be tested again after a certain period, depending on the result.
- To advance the vaccination normally given at 1 year, to 26 weeks. This is to prevent the animal from walking around unprotected until the age of 1 year.
Most puppy buyers receive a puppy that has been vaccinated once in the litter. Such a puppy can be tested 3 weeks after the vaccination. At that moment, it is not always clear whether the antibodies, that are being measured, come from the mother or from the vaccine. Therefore, a few weeks later, a new titer test is required. If the titers have dropped, then it is certain that these are maternally derived antibodies. Depending on the level of the antibodies (antibody titers) at that time, the pup can then be vaccinated or be retested at intervals of a few weeks, when they are sufficiently low to vaccinate successfully. If the titers remained the same, then this is a sign that the vaccination has been successful. Unfortunately, most puppies in the Netherlands and Belgium are usually only vaccinated against distemper and parvo, so they still have to be vaccinated with a cocktail that also contains infectious hepatitis.
The best and most effective method is to titer test a pup, who has not yet been vaccinated, just before it leaves the litter. If the test shows that sufficient maternally derived antibodies are still present, vaccination is pointless, as the antibodies will neutralize the vaccine. You would then retest the pup, who is probably already with the new owner, after about 3 weeks. If the level of antibodies has declined below the protective level and the level at which a vaccination can immunize, a cocktail containing modified live viruses of infectious hepatitis, parvo and distemper has to be administered.
Subsequently, a titer test is performed about 3 to 4 weeks after this vaccination, to see if the puppy actually has enough antibodies in the blood, and is protected against the diseases mentioned. If this is the case, it means that the dog is immunized and fully protected against the mentioned diseases, by just one vaccination. As the animal is still very young and the immune system has not yet fully developed, a year later it makes sense to test it again to see if the protection is still good. If this is the case, titer testing can be performed triennially, according to the WSAVA guidelines.
The most commonly used titer test is VacciCheck. This is a reliable in-house test which can be performed by the veterinarian himself. Only a very small drop of blood is needed and the result is known within half an hour. The veterinarian must indicate in the vaccination pet passport how long the dog will be protected and thus, a validity period is linked to the declaration, according to Dibevo, KNMvD, NVWA and KMSH.