DR. SANJEEV KR SINGH, PET CONSULTANT, HYDERABAD
Vaccination Failures in Dogs
When a vaccinated dog develops the disease against which she was vaccinated, it is often referred to as vaccine failure. In most cases, however, it is not the vaccine that has failed, but rather it was an inadequate immune response to the vaccine. All of our pets are susceptible to a variety of infectious diseases. Fortunately, we have vaccinations that help protect them against most of these diseases. While cases of some of these conditions may be rare, it is still important to ensure they are up to date on vaccinations.
Unlike immunizations in people, it is essential to have your pet vaccinated annually, as some of the vaccines only provide one year of immunity or coverage. Keep in mind that if you are late for your booster vaccination, you may have to restart the series all over again to ensure adequate protection.
Listed below are some of the main reasons disease may occur in vaccinated dogs.
Maternal Antibody
Newborn puppies receive disease protection from their mother through the transfer of antibodies. These antibodies are transferred from the mother through the placenta and through colostrum, the first milk the newborns receive. Antibodies are small disease-fighting proteins produced by certain types of cells called “B cells.” The proteins are made in response to foreign particles such as bacteria or viruses. These antibodies bind with certain proteins (antigens) on foreign particles like bacteria, to help inactivate them.
The age at which puppies can effectively be immunized is proportional to the amount of antibody protection the young animals received from their mother. High levels of maternal antibodies present in a puppy’s bloodstream will block the effectiveness of a vaccine. When the maternal antibodies drop to a low enough level in the puppy, immunity (protection from disease) can be produced through vaccination.
The antibodies from the mother generally circulate in the newborn’s blood for a number of weeks. There is a period of time from several days to several weeks in which the maternal antibodies are too low to provide protection against the disease, but too high to allow a vaccine to work. This period is called the window of susceptibility. This is the time when despite being vaccinated, a puppy can still contract the disease. This window of susceptibility can vary widely. The length and timing of the window of susceptibility is different in every litter and between animals in the same litter. Canine parvovirus is a good example of this.
A study of a cross section of different puppies showed that the age at which they were able to respond to a vaccine and develop protection (become immunized) covered a wide period of time. At six weeks of age, 25% of the puppies could be immunized. At 9 weeks, 40% of the puppies were able to respond to the vaccine and were protected. The number increased to 60% by 16 weeks, and by 18 weeks, 95% of the puppies could be immunized.
Some vaccines can stimulate active immunity in the young pup even when maternal antibodies are present. One type is called a high titer, low passage vaccine. This modified live vaccine contains a higher number of virus particles (high titer) which are less attenuated (low passage) than the “average” vaccine. Another type, the recombinant vaccine, is made from portions of the genes of the virus or bacteria. Those genes that code for the antigens that produce the best antibody response are combined with a non-disease causing virus so they can enter the cells of the body. Both the high titer, low passage vaccines and recombinant vaccines can generally generate an immune system response in young animals who have a maternal antibody level that would prevent them from responding to an”average” vaccine. As vaccines improve, hopefully puppies will be better able to protect puppies throughout their early life.
Insufficient Time Between Vaccination and Exposure
A vaccine does not immediately provide protection. It takes several days to a week or more for an animal’s body to respond to the vaccine. For some vaccines, lyme vaccine, for example, an adequate level of immunity usually does not occur until 2-3 weeks after the second vaccination in the series. A young animal is susceptible to a disease if it is exposed to the disease before a vaccination has had time to stimulate the body’s immunity. A puppy vaccinated against parvovirus, and then exposed to the virus several days later, would probably develop the disease. In the same way, a vaccine will not provide protection to a puppy who was already exposed to the disease before vaccination.
Too short of an interval between vaccination and exposure to disease can result in the dog developing the disease. In some cases, the same is true if the length of time between vaccination and exposure to disease is too long. Some vaccinations may protect the animal for life. Other vaccines produce a protection that lasts only a short time (short duration of immunity). These vaccines will need to be boostered. For dogs, these include vaccines against Lyme disease, leptospirosis, and Bordetella (one of the causes of kennel cough). The length of protection from a vaccine varies by the disease, type of vaccine, age at vaccination, and the immune system of the individual animal.
Antibody Titer
Sometimes veterinarians try to determine if an animal has protection from a disease by measuring the amount of antibodies in the blood. The result is often expressed as a titer. The test is usually performed by making a number of dilutions of the blood and then measuring at what dilution there is sufficient antibody to react in the test. For example, a titer of 1:8 (one to eight) means the blood can be diluted to one part blood and seven parts saline and still produce a positive reaction in the test. The higher the titer (1:16 is higher than 1:8), the more antibody is present.
Interpretation of titers becomes more complicated. The protective titer for canine distemper is 1:20, however, the protective titer for feline panleukopenia is 1:100. You can not compare titers between diseases – a protective titer for one disease will be different than that for another disease. Also, the titer is only a measurement of one part of the immune system – the antibody level. It does not test the remainder of the immune system which can play a very large role in preventing disease.
Some veterinarians suggest we should measure antibody titers before revaccinating the pet. If the animal has a protective titer, a vaccine would not be given. At this time the protective titer of many diseases is unknown. For some diseases the level of antibody would not accurately assess the immune status of the animal because other parts of the immune system are more important for fighting off that particular disease. Another problem with titers is that the test will only determine the animal’s status at that point in time. It cannot determine what the animal’s status will be 6 months from now. That leads to the problem of not knowing how frequently a dog’s titers should be tested. Finally, there is always the possibility of laboratory error. A test result may erroneously suggest an animal has a protective titer when she really does not.
Different Strain of Bacteria or Virus
Vaccines only contain specific strains of the virus or bacteria that causes disease. A vaccine produced from one strain may not adequately protect against another strain. As an example, some vaccines against leptospirosis only protect against two types of the bacteria, while others protect against four different types.
Damage to Vaccine
If not handled properly, it is possible that a modified live vaccine could be inactivated. This is a very uncommon occurrence, but could occur if the vaccine was exposed to ultraviolet light, if there was a long time period between when it was reconstituted and when it was used, or if it was not stored at the proper temperature. Manufacturers realize some of the vaccine particles could be reduced through handling and have made allowances for this when determining how many vaccine particles should be included in each vaccine.
Improper Administration
Vaccines are developed to be given by a certain route, either intranasally (into the nostrils), subcutaneously (under the skin), or intramuscularly (into the muscle), or orally (by mouth). If a vaccine is administered by a route different from the route for which it was developed, it may not be effective and could cause considerable harm.
The entire dose of the vaccine should be given at one time. Vaccines are not developed to give different doses to different size animals, except in some cases, it is recommended that the dose of intranasal vaccines for kittens be reduced.
Nonadherence to Vaccination Schedule
There are several circumstances in which failure to follow the recommended vaccination schedule will result in vaccine failure.
Vaccine Interference
If too short of a time elapses between doses of vaccines, vaccine interference can occur.
Prolonged Interval Between Vaccinations
To provide the best response, the first time an animal is being vaccinated against a disease, repeated vaccinations are usually given 2-4 weeks after the prior vaccination. The first vaccine more-or-less primes the immune system, and the subsequent vaccination(s) increase the immune response. If a period longer than several weeks occurs between this first series of vaccinations, the immune system is no longer as “primed” and less of an immune response may result from the subsequent vaccination.
Genetics
It appears that some breeds of dogs may be more susceptible to certain diseases. Dobermans and Rottweilers, for instance, tend to be more susceptible to canine parvovirus, and may need a different vaccination schedule than other dogs, if they are to be protected through vaccination.
Immunosuppression/Immunodeficiency
To provide protection from a vaccine, an animal’s immune system must be adequately stimulated by the vaccine. If the animal’s immune system is not functioning adequately or is suppressed, as would be the case in animals with certain viral infections, and those receiving certain cancer treatments or very high doses of steroids, the vaccine would not initiate a proper immune response, and would not result in protection from the disease.
Concurrent Disease Process
Fever has been shown to inhibit the response of the immune system to canine distemper vaccination in puppies. Certain viral infections may also decrease the ability of the immune system to adequately respond to a vaccination. Even stress, such as boarding could decrease a dog’s response to a vaccination.
Nutritional Deficiencies
Animals who are malnourished, like those who are ill, may not respond adequately to a vaccination. Poor nutrition, such as Vitamin A, Vitamin E, and selenium deficiencies, and restricted protein or calories can result in suppression of the immune system.
Vaccine and Procedural Factors.
Failure of vaccination can occur because of the innate limitations of the vaccine itself or because the vaccine was either not given properly or stored properly (making it ineffective)or because the animal was allowed to be exposed to infection before the vaccine has had time to have effect.
1)The vaccine was not stored properly.
Vaccines, particularly the live vaccines whichcontain live organisms, are very sensitive to storage conditions. They can not beallowed to get too hot or too cold or come into contact with ice-packs etc. If they do,the vaccine can die and, thus, it will not be effective inducing protective immunity.
2) The vaccine was given past its use-by-date.
The use-by-date is the date the vaccine should be considered reliable to according to vaccine company studies. Live attenuated vaccines, in particular, should be considered to have a finite lifespan(the lifespan of the live organisms), after which the vet might simply end up inoculatinguseless, dead organisms into the animal.
3) The vaccine was not injected within a certain period of time after reconstitution.
When a vaccine arrives at a vet, it is usually in a powered, dried form that needs tobe mixed in a diluent before injection. If the vet makes up the vaccine (mixes itin diluent) and leaves it sitting on a bench or in a fridge for more than a couple of hours,the vaccine will become inactive and ineffective at inducing immunity.
4) The vaccine was not given according to company vaccine recommendations(vaccine guidelines).
All vaccines are thoroughly tested by vaccine makers duringproduction and, as a result of this testing, the manufacturers come up with a list of vaccine protocols and recommendations by which the vaccine should be given if it is to achieve its best effect.These might be important guidelines designed to overcome maternal immunity; important protocols designed toachieve a stronger, longer duration immune response (e.g. you need a minimum of at least two doses of a killed vaccine to achieve the desired response) or important protocolsdesigned to reduce the risk of vaccine side effects. If the vet does not follow thesecompany guidelines and administer the vaccine according to the schedules set outby the company, the animal may not be protected adequately against disease.
This also applies to timing of boosters. Vaccines do not provide indefinite protectionand booster vaccinations are needed to provide ongoing cover.
5) Disinfecting the skin with alcohol or antiseptics can potentially render the vaccine ineffective. Sterilising syringes and needles can also leave residues thatmay kill off the vaccine organisms.
6) Certain types of vaccines are less effective at inducing a protective immuneresponse than others.
Generally live vaccines induce a much stronger and longer-lastingduration of cell-mediated and humoral immunity than killed vaccines do.
7) The puppy or kitten was exposed to wild-type infectious disease organisms beforeit was fully protected by the vaccines.
It takes time for vaccines to inducea protective immune response in a young animal. The time taken varies according tothe individual type of vaccine, with some vaccines only achieving full protectionafter a course of 2-3 injections has been completed and other vaccines (e.g. some of the newer Fort Dodge and Intervet vaccines) giving full cover within a week ofjust a single dose (e.g. Nobivac DHP and DuramuneAdult C3) or within three days of an intranasal vaccine (e.g. Nobivac KC).The consequence of this is that, even though your puppy or kitten might have been given a needle recently by your vet, this does not mean that it is protected and thatit is yet ready to meet other dogs and cats or walk in public places (which couldbe contaminated with diseases).
A major cause of vaccine failure is taking pups and kittens out to meet with otheranimals before they are fully protected. Be sure to ask your veterinarian whenpuppies and kittens can start socializing safely.
Another potential risk is bringing diseases home with you. If you have visited a place where there has been a parvovirus infection or an outbreak of kennel cough or cat flu, don’t bring these diseases back to your house where your unprotected puppy or kittencan catch them! Change your clothes, disinfect your shoes (with parvo, this disinfectionrequires powerful chemical virucides like bleach) and shower thoroughly (including washing your hair)before greeting your pet. Ideally, disinfection should take place somewhere other thanyour own home. The same precautions should be taken when other people visit your home:ask them if they have had any potential contact with infectious diseases.
Vaccines for Dogs
Vaccine schedules can be complicated and confusing and many options for vaccines depend on the lifestyle of your dog and on any medical problems as well.
Core Dog Vaccines – These are the two core vaccines that we feel all dogs should receive:
- DHLPP (which is a combination vaccine of distemper, hepatitis, leptospirosis, parainfluenza, and parvo). Adult dogs are moved to DHLPP every 3 years after the age of one year old.
- Rabies: Rabies is our only vaccine that is regulated by the state and county.
What diseases do these core vaccines treat?
- Distemper(the D in DHPP) – This disease is a paramyxovirus, which is similar to human measles. It can cause fever, poor appetite, pneumonia and can continue on to cause neurologic symptoms (which can be permanent) and death. It is transmitted mainly through saliva but can be potentially transmitted through any secretion.
- Hepatitis(the H in DHPP) – This disease is caused by an adenovirus. It primarily causes liver failure but can also affect the eyes and kidneys. The symptoms can include vomiting, diarrhea, changes in the cornea of the eye and even death. It is transmitted by bodily fluids, especially nasal discharge and urine.
- Leptospirosis— This is a bacterium that is found in many types of outdoor environments. There are over 200+ strains for this bacterium. The vaccine does not cross-protect (basically each strain needs its own vaccine). The symptoms can be kidney or liver failure, severe lethargy, fever, lack of appetite, vomiting, diarrhea and increased drinking/urination. Permanent kidney damage or death can also occur. It is transmitted through urine, with contaminated water a likely source. This can be transmitted from dogs to humans; therefore it is considered a zoonotic disease.
- Parainfluenza(the first P in DHPP) – The parainfluenza virus is one of several agents that can be part of the tracheobronchitis (kennel cough) disease. This virus causes mild disease unless combined with another virus or the Bordetella bacteria. It causes a dry hacking cough and watery nasal discharge but can progress to pneumonia. If left untreated it can even cause death. It is transmitted by saliva and nasal discharge.
- Parvo(the second P in DHPP) – This virus can cause severe, bloody diarrhea, severe dehydration, electrolyte imbalances and frequently death. It is transmitted through the feces. This virus is very hardy and can live in the environment for months under the right conditions.
- Rabies–Rabies is a very serious disease transmitted by saliva either by bite wounds or saliva contact with open wounds. Incubation from time of exposure to symptoms is usually 3-6 weeks in the dog but can be as long as 6 months. It attacks brain cells and causes neurologic symptoms. Once an animal gets rabies it is always fatal. Vaccination for rabies is required by state law for dogs and in many communities keeping cats up to date with their rabies vaccine is also required. There is a 1-year and a 3-year vaccine. It will depend on the county in which you are living to which one the county requires.
Non–core vaccines – These three vaccines are based on lifestyle and exposure:
- Bordetella — Bordetella is done yearly for those dogs boarding and grooming.
- Influenza – Canine flu is done once a year for those dogs boarding and grooming.
What diseases do these non-core vaccines treat?
- Bordetella(also known as Kennel Cough) – This disease is usually caused by more than one virus and/or bacteria. Usually Bordetella bacteria and Parainfluenza virus are the main culprits. However, Herpes virus, Distemper and several other viruses can also be involved. The disease is spread by nasal discharge or fomites. This vaccine goes into the nose instead of being injected under the skin.
- Influenza(H3N8) – This vaccine works for this strain of Influenza only. Our current outbreak is related to the H3N2 strain and therefore this vaccine is only recommended for those boarding facilities that are requiring it.
Side effects or adverse reactions
Because vaccines stimulate the animal’s immune system, minor reactions may sometimes occur afterwards. The most common of these occur within the first few hours following vaccination and include allergic reactions, sensitivity of the vaccinated area, and fever, and these symptoms generally pass within a day or two.
Less likely side effects that may occur include an immune disease related to the vaccine, or small granulomas (tumours) at the injection site. These granulomas should be monitored carefully.
If you see your pet experiencing any of the following symptoms for more than two days, take them to the Vet immediately:
- weakness
- breathing difficulties
- vomiting
- loss of appetite
- diarrhoea
Uncommon side effects of vaccination can include:
- haemolytic anaemia
- reproductive system issues
- temporary limping (in cats)
- sarcomas (in cats)
Sarcomas may be one of the worst side effects of vaccination, however these tumours are mainly linked to a type of vaccine not routinely given in Australia. An early detection can result in a positive extraction of the tumour, so monitor your cat closely to ensure they stay safe.
It is important to keep in mind that these side effects are considered less risky in comparison to potentially exposing your animal to serious diseases if they remain unvaccinated. Vaccines are an essential aspect of care for household pets, and have played a key role in preventing communicable diseases and fostering early detection and treatment of medical issues.
https://www.germantownah.com/site/blog-memphis-vet/2020/01/07/dog-vaccination-schedule-need-to-know
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