Preventative Medicine: Vaccines

In this article we will address what vaccines are, what diseases they work against, and what are the pros and cons of giving vaccines. Hopefully, after this article, you will be better informed about their importance.

Vaccinations are injections that prevent diseases. Most vaccines work by containing an inactivated (or non-illness causing) form of the virus or bacteria, or by only containing a small portion of the virus. These injections stimulate the immune system to start producing antibodies against the diseases contained in the vaccine. Antibodies help the immune system to mount a stiff resistance against the disease if your pet becomes infected. Due to the swift nature of the immune system, antibodies are made very quickly against a disease so long as there has been previous exposure (such as previous illness or previous vaccination.) Because the immune system is being stimulated, vaccines do have potential complications, which we call reactions. These reactions will be dealt with later in the article.

We start vaccinating dogs at 8 weeks of age. This is the perfect age to start, as antibodies that they got from their mothers are beginning to decline. These antibodies, that come from the placenta (umbilical cord) or through the colostrum (the first day of breast milk) help the puppy or kitten to fight off diseases which the mother is already immune to. If vaccination is started too early, the vaccine only uses up the antibodies already present, and actually decreases immunity. Vaccinations build on each other to help stimulate strong immunity in young dogs and cats, that is why multiple vaccines are required. Starting at 8 weeks, puppies should get their vaccinations for every 3 weeks, until the series is finished. Their immunity against these diseases is not complete until they finish their vaccine series. Just because they had their first shots does not guarantee immunity.

Dog vaccines:

• Distemper: This is a multi-system virus. It is frequently fatal. Symptoms include vomiting, diarrhea, coughing, nasal discharge, crusting around the eyes and feet, anorexia, lethargy, and neurologic signs (tremors, convulsions, and seizures). It is secreted in body fluids and can be aerosolized (in the air) from infected dogs. It can be carried on clothes. Dogs who are most at risk are dogs from high populations (pound, pet store, breeding kennels, boarding or grooming kennels) or frequent areas such as parks, which infected dogs, may frequent. The vaccine is very good and quite protective. It is the "D" in the DHPPC vaccine. Depending on the type of vaccine given, it lasts for 1 year or 3 years.
  
• Parvo: This virus attacks rapidly dividing cells, such as the intestine and in puppies, the bone marrow. This disease, even with aggressive treatment can still be fatal. Symptoms include vomiting (which may be bloody or coffee ground in appearance), diarrhea (which is almost always bloody and very foul smelling), and lethargy. It is shed in body fluids from infected animals and can be carried on the clothes of those around the infected dog. In fact, this virus is very hardy and can live in the environment for a very long time, weeks to months. Veterinary hospitals, grooming shops, boarding kennels, pet stores, and pounds fear it especially because it resists attempts to kill it with disinfectants. Sometimes entire facilities must be closed down for decontamination if an outbreak occurs. This disease was devastating in the 1980's, but vaccination has been very good at slowing its spread and here we only see a few cases a year. At one point in the 1980's, before the vaccine was available, Dr. Dahlem had to close the hospital too all patients except those with Parvo because there were so many patients here with it. This is one of the "P"'s in the DHPPC vaccine and also comes by itself. Like the Distemper it is given annually or every 3 years depending on the vaccine given.
  
• Hepatitis: This is not the same disease that people get, and is not contagious to people. This virus damages the liver, spleen, lungs, and kidneys. Symptoms can include vomiting, fever, diarrhea, and coughing. This disease is almost always fatal to puppies. They just "fade" and waste and die. This vaccine is so good; that we hardly see the disease anymore, although it is still present in areas which vaccination is not routinely performed. This is the "H" in the DHPPC vaccine. It is given every year or every 3 years depending on the vaccine given.
  
• Coronavirus: This is a highly contagious intestinal disease. Symptoms include vomiting, diarrhea, and lethargy. It frequently is seen along with Parvovirus, that makes the situation much worse. Dogs in high populations are most at risk. It is the "C" in the DHPPC vaccine. It is given annually.
  
• Parainfluenza: This is a respiratory virus that causes coughing. It is frequently associated with other respiratory infections. It is one of the causes of Kennel Cough, which is a loud hacking dry cough with some retching at the end. While rarely fatal, this disease is highly irritating to both dog and owner and highly contagious. Dogs in high populations are at high risk, but dogs that go to parks or visit an infected dog are at risk. Dogs do not have to be coughing in order to spread the disease. We see kennel cough almost 80% of the time from dogs from the pound. This vaccine is the other "P" in the DHPPC vaccine. It also is frequently incorporated into the Bordetella vaccine. It is given annually.
  
• Bordetella: This is a bacterium that is a common cause of kennel cough. It is isolated very commonly from dogs with the disease. See Parainfluenza for more information. Bordetella has also been isolated from cats, guinea pigs, rabbits, and humans. There are many strains and whether the bacteria causes disease in people or cats is still being researched and debated among veterinarians and medical doctors who specialize in diseases transmitted from animals to people. This vaccine comes in an injectable and nasal version. The nasal version works much better, but can't be used in certain, aggressive dogs. Unfortunately, the vaccine is not perfect, as it doesn't protect 100% and vaccines do not exist for all of the causes of Kennel Cough. It does help to reduce severity and the duration of illness though. It is given annually.
  
• Giardia: This is a single celled parasite, which can infect all mammals. It is caused by fecal contamination, usually of spreading Giardia spores into water. Most dogs (and people) get the disease from drinking from untreated streams, rivers, and lakes. Dogs can get it locally from poor hygiene at a high population area, drink dew from grass near infected feces (poop), drinking puddle or gutter water, or ingesting/licking infected feces from other animals (gross!!!) This disease can cause a severe foul-smelling diarrhea and cramping. These dogs sometimes need hospitalization during treatment (which is not 100% effective). Dogs can also become carriers, and have the disease without symptoms. This disease is very difficult to detect, and sometimes, special tests must be performed to identify it. This disease can also be transmitted from dogs to people, especially children and immune-suppressed individuals (such as elderly, patents undergoing chemotherapy, or HIV infected people.) People, who are infected, generally need to be hospitalized and don't tolerate the medication very well. This vaccine is given annually.
  
• Leptospirosis: This is a group of bacteria that cause severe liver and kidney infections. It is found from water contamination, usually by cattle. It can spread in high population areas as well. Historically, this disease was part of the DHLPPC vaccine, but was removed. It frequently caused severe vaccine reactions and was found to be non-protective. There are 5 strains of the bacteria, and the vaccine protected against 2 strains and dogs were getting the other 3. Recently, a new vaccine is available for those other strains. In this area the risk is low (no cattle) and we do not routinely give this vaccine. Certainly travel to a high-risk area would warrant vaccination. Certain boarding facilities require it as well. We do have the vaccine available upon request. We require monitoring throughout the day here or at home if this vaccine is given. If given, it is given annually.
  
• Lyme Disease: This is a multi-system disease spread by ticks. While the disease does affect people as well, it is not directly contagious to people. This bacterium requires a tick bite in order to be spread. Symptoms include fever, joint pain, lethargy, and a rash where the bite occurred. It is very rare in this area. Our viewpoint is that proper tick prevention is all that is necessary in this region. Monthly Frontline to kill ticks and using a Preventic collar or Flea Spray to repel fleas if traveling in brush should suffice. We do have ticks here in Orange. If traveling to a high risk area or if ticks are especially a problem, we recommend the vaccine, but it its not a part of our routine vaccine series. It is given annually.
  
• ProHeart: As of September 3, 2004 the FDA recalled this heartworm preventative due to reactions more severe than initial safety studies indicated. Investigation is pending. This shot was given every 6 months to prevent heartworm disease. At this time, for heartworm prevention we are recommending monthly oral heartworm prevention. In 2001 there were 35 reported cases of heartworm disease in dogs in Orange County. The actual number of cases was probably much higher. While this risk, luckily, is low, it is a nasty disease and there could be many complications from treatment. We've seen 4 cases of heartworm here at Orange Villa in the last 5 years.
  
• Rabies: This disease is 100% fatal in dogs and almost 100% fatal in people if untreated (one person didn't die but was "a vegetable"). This is the only legally required vaccine in dogs. You will be fined if your dog is not vaccinated by 16 weeks of age. It is required for licensing. This virus is found in very high concentrations in saliva; bite wounds are the routes of infection. Most of you have read or seen Old Yeller, so you know the disease is bad. In this area, the vectors (or cause of spread) of the disease are Skunks and Mexican Freetail Bats. If you see a bat flopping on the ground or during the day, it is likely rabid. Do not touch it. If your dog is playing with it, you need to contact your veterinarian and animal control will be notified. If you see a skunk out during the day, it could be rabid, call animal control. All mammals can get this disease. Luckily, in our area, it is quite rare due to great vaccination protocols. It is boostered at 1 year of age, then every 3 years.

Cat Vaccines:

• Panleukopenia: Is sometimes mistakenly called feline distemper. It is a parvovirus, which means that it is hardy. It is mainly found in high population areas (boarding, grooming, catteries (cat breeding facilities), pet stores, and pounds.) Last year the Orange County Shelter had a serious outbreak. This disease causes fever, vomiting, and diarrhea. It is frequently fatal to kittens and can cause severe brain disorders to kittens if a pregnant female (queen) is exposed. The vaccine is very good. It is the "P" in the FVRCP vaccine.
  
• Feline Viral Rhinotracheitis: This herpes virus is not contagious to people or dogs, just cats. It causes sneezing, congestion, irritated eyes, conjunctivitis (kitty pink eye) and eye ulcers. Congested cats will sometimes stop eating which can require hospitalization. This disease is frequently complicated by secondary bacterial infections. Like all herpes viruses, the virus is never completely eliminated. Adult cats can get symptoms again after stress. Some cats can get chronic nasal or eye problems from infection. The disease is very contagious and airborne. Cats do not have to be sneezing to spread the disease. It is most common in high population areas, but indoor cats can be infected through screen doors. The vaccine is not 100% effective, but certainly reduces severity and duration of illness. We see this very commonly from kittens and cats from the shelter and other viruses and bacteria that cause upper respiratory symptoms. It is the "FVR" part of the FVRCP vaccine.
  
• Calicivirus: This is another upper respiratory virus. It can cause the above symptoms, plus oral ulcerations. It is believed to be a cause of chronic oral lesions in cats. It is the "C" in the FVRCP vaccine.
  
• Chlamydia: is a bacterium, which affects birds, cats, and people. In cats, it causes upper respiratory signs (pneumonitis) and contributes to the other causes. The primary symptom is eye discharge, but sneezing and nasal discharge are common as well.
  
• Feline Infectious Peritonitis: This disease is a mutation of a common intestinal coronavirus. This mutation occurs in 10% of cats infected with a corona virus. Cats in a high population environment are most at risk, as it is quite contagious from fluids or clothes. This disease can affect the brain, eyes, liver, kidneys, lungs, heart, and cause inflammation and fluid build up in the chest or abdomen (peritonitis). It is almost always fatal. Testing is difficult, as most tests only check for a coronavirus. Only testing on fluid or biopsy is confirmatory. The vaccine is nasal, which while effective is difficult to give to cats.
  
• Giardia: This is a single celled parasite, which can infect all mammals. It is caused by fecal contamination, usually of spreading Giardia spores into water. Most cats (and people) get the disease from drinking from untreated streams, rivers, and lakes. Cats can get it locally from poor hygiene at a high population area, drink dew from grass near infected feces (poop), drinking puddle or gutter water, or ingesting/licking infected feces from other animals (gross!!!) This disease can cause a severe foul-smelling diarrhea and cramping. It is common in kittens, especially from the pound. These cats sometimes need hospitalization during treatment (which is not 100% effective). They can also become carriers, and have the disease without symptoms. This disease is very difficult to detect, and sometimes, special tests must be performed to identify it. This disease can also be transmitted from dogs to people, especially children and immune-suppressed individuals (such as elderly, patents undergoing chemotherapy, or HIV infected people.) People, who are infected, generally need to be hospitalized and don't tolerate the medication very well.
  
• Rabies: This disease is 100% fatal in and cats and almost 100% fatal in people if untreated (one person didn't die but was "a vegetable"). This is the only legally required vaccine for dogs. This virus is found in very high concentrations in saliva; bite wounds are the routes of infection. Most of you have read or seen Old Yeller, so you know the disease is bad. In this area, the vectors (or cause of spread) of the disease are Skunks and Mexican Freetail Bats. If you see a bat flopping on the ground or during the day, it is likely rabid. Do not touch it. If your cat is playing with it, you need to contact your veterinarian and animal control will be notified. If you see a skunk out during the day, it could be rabid, call animal control. All mammals can get this disease. Luckily, in our area, it is quite rare due to great vaccination protocols.
  
• Feline Leukemia Virus: This is a retrovirus that commonly affects the bone marrow. It is spread through bite wounds and sexual intercourse with other cats. Outdoor cats and cats that tend to get outside are at highest risk. In high population areas, infected cats can bite tails and paws sticking out of cages. Kittens can be born with the disease. Frequently, adult indoor cats are infected when a new stray is adopted. Some infected cats can get over the disease, while most develop a chronic state, in which they are carriers. They don't show symptoms but can spread the disease. Eventually, weeks to years later, they start to show symptoms. The disease causes immune suppression, so that they get sick often from secondary illnesses. The virus is also an oncovirus, which means that it is a cancer-causing virus. There is a test for this disease. All kittens should be tested, and all cats before vaccination are started. The test does have some false positives, so if a positive result occurs, then a special re-test is performed. If your cat is positive, they must remain indoors with no other cats to prevent spread of the disease. Cats can live for up to several years with the disease so a positive result doesn't mean that euthanasia is required. There is a good vaccine for this disease called the FeLV vaccine.
  
• Feline Immuno-deficiency Virus: The disease, FIV, or Feline AIDS is a lentivirus, just like HIV. It is not contagious to people. It causes immune suppression, just like FeLV. Infected cats get the disease mostly through bite wounds, because there is very high levels in the saliva. Outdoor cats are at highest risk. Unlike FeLV, infected cats very rarely are able to rid themselves of the disease. Kittens can be born with the disease. Cats can live with the disease for years, but must be kept indoors. Cats with the disease eventually succumb to secondary infections. Severe mouth lesions are frequently seen with cats with FIV. There is a new vaccine available. It is about 85% effective. This vaccine does seroconvert, or makes a cat that is vaccinated test positive for the disease. Hopefully, a new test will be available soon to keep this from happening. We are recommending vaccination for cats that are at high risk. Hopefully, the research for this disease will help develop an HIV vaccine for people.
  
• Vaccines for Ringworm and Bordetella: These do exist, but they are not all that effective and are not considered necessary by our doctors. Bordetella is a bacterium that is a common cause of kennel cough. It is isolated very commonly from dogs with the disease. Bordetella has also been isolated from cats, guinea pigs, rabbits, and humans. There are many strains and whether the bacteria causes disease in people or cats is still be researched and debated among veterinarians and medical doctors who specialize in diseases transmitted from animals to people. It has been isolated from sick and healthy cats, and it is unknown how strong a role it plays in upper respiratory infections. The ringworm vaccine (a soil-fungus) is not very effective and the disease is generally easily treated.

Now that you know about the vaccines, comes the difficult decision of whether or not to vaccinate and if so, how often. Coming into play into that decision is vaccine reactions. Vaccine reactions are basically, an unwanted side effect of the vaccine. Anything given to any animal can cause a reaction, an inappropriate immune or chemical reaction. This can include drugs, such as antibiotics, anesthetic agents, herbal supplements, shampoos, flea products, food, insect stings, infections, or environmental allergens such as cigarette smoke. Reactions can occur in any dog at any age, even if they have received vaccines or the same medication before with no problems. Vaccines and other medications are of course, of special note because we are trying to prevent or treat disease, and we end up causing problems. Luckily, these reactions are very rare. Less than 1% of dogs and cats vaccinated develop any side effect at all. Of that 1-%, most get a mild fever and lethargy for a day or so. Unfortunately, more severe reactions are possible. Short-term reactions seen are:

• vomiting
• diarrhea
• pain where the injection was given
• moderate lethargy and fever/anorexia
• facial swelling
• hives

If these reactions occur, you should bring it to the attention of your veterinarian right away, as medical treatment may be necessary to stop the reaction and end symptoms. Also pets that react once usually do so again. Pre-medication with an antihistamine or steroid may be necessary to prevent a recurrence.

A much more severe and life-threatening reaction can occur. This is called anaphylaxis, and it is a severe allergic reaction, which causes swelling of the airways and dropping of the blood pressure. Thus is an emergency and prompt treatment is required. Pets that get this type of reaction should not receive vaccines in the future.

What about long term reactions. Autoimmune diseases, where the immune system starts attacking parts of the body certainly occur. Immunologists feel that any protein (such as those in vaccines) can cause a reaction to occur. Luckily, these diseases are quite rare. They can occur well after the vaccine was given, which makes proving that a vaccine was at cause difficult. Only one such reaction, which causes hair loss in Poodles and Yorkies secondary to Rabies vaccination, is well proven. The rest of the data is unfortunately, pure conjecture at this point. We discuss at length whether dogs with a history of autoimmune disease should be vaccinated with the owners.

What about this feline sarcoma-thing? Should I worry? Vaccine-induced sarcomas are caused by a too exuberant immune response in cats to the vaccines. It used to be thought that it was caused by the adjuvant (the material in viral vaccines to makes them work better) but researchers have found reactions to more than just the vaccines, but to almost any injection. We just don't understand why they happen, yet. Luckily, they are quite rare, less than 1:40000 cats form these reactions. Because of the risk, we ask you, the cat owner, to monitor the spots where the vaccines are given. If you feel any lumps where they were given, which can be months to years after vaccination, please bring your cat in right away. With prompt treatment, the sarcoma can be removed and everything will be fine. These sarcomas are invasive but do not spread elsewhere. We feel that the risk of sarcomas, which is low and they are treatable, are much lower than the diseases we vaccinate for (which are more common and not treatable in many cases.)

We have heard stories of vaccines causing liver or kidney disease, or brain tumors in dogs. There is absolutely no data to substantiate these claims. If comparing average lifespans of dogs from the 1980's, 1990's, and today, pets are living longer and more disease-free than ever. They average age of pets is climbing every year, in spite of increased vaccination. Reactions are possible, but the numbers of dogs that get reactions is much, much lower than the numbers of dogs that would get these diseases if vaccination were not performed. It's important to also remember that vaccines have been helping to remind pet owners to bring in their pets for annual examination, which is of course extremely important. Even those who go to vaccine clinics or vaccinate at home must bring their pets in for examination to identify and prevent disease.

Knowing the risk vs. benefit of vaccination, how often are vaccines necessary? We have had numerous questions as to how often to vaccinate. Unfortunately, there are no easy answers. We use the Fort Dodge vaccine series for most of our vaccines. Fort Dodge makes some of the most potent and effective vaccines. They have studies, which carry immunity against disease out to 1 to 3 years. Unfortunately, they did not do a study for longer than that (no vaccine manufacturer has.) That means that we have no way to measure how much longer than recommended each vaccine lasts. Theoretically, this means that the longer a pet goes after the tested duration, the lower immunity gets. This could mean a slight lowering (1-2%) per year or a lot (50-75%) lowering. There is not a lot of research into this unfortunately. Some vaccines, such as Distemper and Hepatitis have had a very long immunity in some studies, but likely the others do not. Unfortunately, to minimize the poking (how many times a needle sticks your pet) these viruses are combined into other vaccines.

With cats, outdoor and high population cats are at high risk for these diseases. Indoor cats are less so. In our area outdoor cats don't live long due to coyotes, so we see a little bit less of the diseases than other areas. But with FeLV and FIV, it only takes a minute for an indoor cat to get bit by the neighborhood tomcat. Again, you should talk with the doctor about straying from the protocols.

So the question is how often to vaccinate. What will need to be taken into consideration is risk. Is your pet in a high-risk group? Dogs that get boarded, groomed, go to the park or around other dogs are in a high-risk group. Dogs that don't leave the lap or the yard are a low-risk group (but still present.) Certainly, we feel high-risk dogs must be vaccinated annually for Bordetella, corona, giardia, and parainfluenza. Distemper, Parvo, and hepatitis can be boostered every 3 years or annually depending on vaccine used. Dogs that are not high risk, you should discuss with the doctor. You may feel that the decrease in immunity isn't worth the risk of reaction. If so, this should be a discussion between the doctor and you. Rabies is required by law.

What if I choose not to vaccinate or do so less often and I need my pet boarded or groomed? There is an alternative. There are special blood tests, called titers, which can measure immunity to different diseases. We can test for immunity against Distemper and Parvo. With cats we can test for immunity against Calici Virus, Panleukopenia, and Chlamydia. We can test for leukemia and FIV in cats. These tests do have drawbacks. They are much more expensive than vaccines. They can also take 10-14 days for results to be back. This means for dogs and cats coming in for grooming, they need to come in a few days beforehand for the testing in order to know their immunity status by the time they come to stay. Also these titers only test immunity at that moment in time, they do not check to see if immunity is rising or falling. We titer annually, but immunity may be compromised in 6 months.

If you choose not to give vaccines annually, it is imperative that you remember to bring your dog to the veterinarian every 6 months for a wellness exam. We combine our vaccination visits with wellness examinations, and if your pet isn't examined regularly, treatable medical problems could be missed at the early stages. Recently, because of individualization of vaccination protocols, we have begun charging these separately, with a reduction in vaccine prices because previously the exam was included with the vaccines.

All in all, we feel that vaccines are a great benefit to the health of your pet. We feel that the risk of disease is much higher than the risk of reaction. All of us vaccinate our pets by our vaccine protocol. But vaccinations are an individual decision, as like any medication, they can have side effects. If you want to discuss this, we encourage it and when it's vaccine time, please discuss the options with the doctor during the examination.