Mar Vista Animal Medical Center

3850 Grand View Blvd.
Los Angeles, CA 90066


FAQ's and General Information


Why do baby animals need a series of shots, and how many do they need?
If a vaccine lasts a person for a lifetime, why do I have to vaccinate my pet annually?
What do I do if my pet skips a year of vaccinations?
What vaccines should I get for my pet?
What vaccine should I get if my pet is indoors almost completely?
What is the difference between a live and a killed vaccine?
What is a "recombinant vaccine" and is it really better than the other available vaccine types?

Why do vaccinated pets still get sick?
Can a pregnant pet be vaccinated?
Can I give vaccines myself?
What is an "adjuvant?"
Why is a feline leukemia test required prior to vaccination?
What is a Vaccine Titer?
Can vaccines hurt my pet?
Can vaccines cause cancer?
Can over-vaccination cause other diseases?How can I have my pets vaccinated at low cost?





When a baby kitten or puppy is born, its immune system is not yet mature; the baby is wide open for infection. Fortunately, nature has a system of protection. The mother produces a special milk in the first few days after giving birth. This milk is called "colostrum" and is rich in all the antibodies that the mother has to offer. As the babies drink this milk, they will be taking in their mother's immunity. After the first couple of days, regular milk is produced and the baby's intestines undergo what is called "closure," which means they are no longer able to take externally produced antibodies into their systems. These first two days are critical to determining what kind of immunity the baby will receive until its own system can take over.

(original graphic by

How long this maternal antibody lasts in a given puppy or kitten is totally individual. It can depend on the birth order of the babies, how well they nursed, and a number of other factors. Maternal antibodies against different diseases wear off after different times. We DO know that by 14-20 weeks of age, maternal antibodies are gone and the baby must be able continue on its own immune system.

While maternal immunity is present in the puppy’s system, any vaccines given will be inactivated. Vaccines will not be able to "take" until maternal antibody has sufficiently dropped. Puppies and kittens receive a series of vaccines ending at a time when we know the baby's own immune system should be able to respond. We could simply wait until the baby is old enough to definitely respond as we do with the rabies vaccination but this could leave a large window of vulnerability if the maternal antibody wanes early. To give babies the best chance of responding to vaccination, we vaccinate intermittently (usually every 2-4 weeks) during this period, in hope of gaining some early protection.

When a vaccine against a specific disease is started for the first time, even in adult animal, it is best to give at least two vaccinations. This is because the second vaccination will produce a much greater (logarithmically greater) response if it is following a vaccine given 2-4 weeks prior.

[Back to Top of Page]



In the U.S., vaccines are licensed based on the minimum duration they can be expected to last. It is expensive to test vaccines across an expanse of years so this is not generally done. If a vaccine is licensed by the USDA for annual use, this means it has been tested and found to be protective to at least 80% of the vaccinated animals a year after they have been vaccinated. Some vaccines are licensed for use every three years and have been tested similarly. Do these vaccines last a lifetime? We cannot say that they do without testing and this kind of testing has yet to be performed.

It is also important to realize that some diseases lend themselves to prevention through vaccination while others do not. For a vaccine to generate solid long lasting immunity, the infection must be fairly generalized to the entire body (like feline distemper or canine parvovirus) rather than localized to one organ system (like kennel cough or feline upper respiratory viruses). Vaccination for localized infections tends to require more frequent boosting whereas there is potential for vaccination for systemic disease to last for many years.

Since the mid-1990’s most veterinary teaching hospitals have restructured their vaccination policies to increase the duration of some vaccines from one year to three years based on independent studies rather than on the studies used by the USDA for vaccine licensing. The American Association of Feline Practitioners has vaccination guidelines for cats living in different exposure situations and the American Animal Hospital Association has guidelines for dogs. These guidelines can be found at:

It is important to realize that these are just guidelines and different regions and different pet lifestyles will justify modifications. For example, Leptospirosis vaccination is generally considered "non-core" but the Los Angeles County Health Dept has recommended that it be considered "core" for Los Angeles County after the substantial 2021 outbreak.

[Back to Top of Page]



It depends on the vaccine and the hospital. Hospitals are likely to have different recommendations as vaccination policy tends to be individualized to the practice and its geographic location. At some hospitals, recommendations for adult animals who skip an annual vaccine include:

  • Feline Distemper (FVRCP) - Vaccinate normally. It is not necessary to restart the initial series.
  • Feline Leukemia (FeLV) - If an adult cat has skipped an annual booster, it is not necessary to restart the initial series and vaccination can simply pick up where it left off.
  • Rabies - A three year vaccine can be given anytime after the initial one year vaccine. This means that if a year is skipped, the next rabies vaccine given will still be a three year vaccine. One year vaccines can be boosted at any time and will be good for one year from the time they are given.
  • Canine distemper, canine parvovirus, nasal bordetella (kennel cough) - Vaccinate normally. You do not need to restart the initial series as though the pet is starting over from the beginning.
  • Canine Influenza - The series should be restarted if longer than 18 months have past since the last dose.
  • Canine Leptospirosis - If longer than 18 months have passed since the last dose, the series should probably be restarted.
  • Lyme Disease - Should a dog in a geographically affected area skip a year with this vaccine, some veterinarians recommend restarting the initial series.
  • Rattlesnake bite vaccination – Because of the complex nature of snake venom, vaccination is recommended every six months. If one has skipped an entire year it would be good to restart the initial series of two vaccines (three for smaller dogs and three for larger dogs).

[Back to Top of Page]



(original graphic by

What vaccines are recommended to an individual pet depend on many factors: what kind of exposure to disease does the animal have, what diseases are common in the area, what kind of stress factors are present etc. When one considers the multitudes of vaccine types and combinations and the many different situations dogs & cats live within, it is not too surprising to find that almost every veterinarian recommends a different group of vaccines. The best advice is to establish a relationship with a veterinary facility that you trust and go with their recommendation. If you wish to determine what shots you want on your own, hopefully this web site will be of use.

To view the Mar Vista Animal Medical Center Vaccination policy and recommendations click here.

[Back to Top of Page]



Both the American Association of Feline Practitioners and the American Animal Hospital Association have published guidelines for vaccination (see above). Vaccinations are divided into “core” vaccines which every pet should have, and “non-core” vaccines which a pet should have depending on their exposure risk.

For cats, core vaccines are the basic distemper shot: feline distemper (panleukopenia), feline herpes and feline calicivirus. Rabies vaccination is core except in Hawaii where rabies has been eradicated. Many people are surprised that rabies is often considered a core vaccine and is considered important even for indoor-only cats but when one considers the consequences of rabies exposure (which can certainly happen indoors) and the legal consequences of owning a biting animal (what happens to the animal generally is dependent on its vaccine status), it is not hard to see why this vaccine is important. The feline advisory board does not consider feline leukemia virus vaccination to be core but they strongly encourage every kitten to be vaccinated against this infection with a re-assessment of risk factors when the kitten is grown. This is because young kittens frequently live indoors only but this often changes when the kitten matures regardless of the original intentions of the owner.


For dogs, core vaccines are the basic distemper shot (DHPP) and the rabies vaccine. Since dogs do go outside for walks, for grooming, to the vet’s office etc. we recommend vaccine against kennel cough for all our canine patients though these are not listed as "core" by the aforementioned organizations. Recently, canine influenza has become a concern in the United States. Dogs that rarely contact other dogs probably do not need vaccination for this but dogs that go to day care, grooming, or boarding facilities should be vaccinated.

[Back to Top of Page]



These terms apply to vaccine against viral infection.

(Photocredit: CDC Public Health Image Library)

The goal of vaccination is to present the virus in question to the patient’s immune system in as natural a way as possible so as to best mimic the stimulation obtained by natural infection yet skip the illness experienced by the patient.

There are two ways to achieve this goal. One way is to use killed vaccine. Here, large amounts of dead virus particles are injected into the patient. They filter into the immune system & lead to stimulation. The other way is to use a live virus that has been "modified" such that actual disease does not result in infection. The live vaccine is able to travel through the body in the same sequence as the naturally occurring virus would, creating immune stimulation in the same way the "street" virus would. An immunity similar to that created by actual infection is produced.

In general, live virus vaccine is preferred as the most thorough immune stimulation will occur with it but there are some circumstances where killed is better. A killed virus vaccine can never revert to virulence, which means there are no circumstances under which the vaccine can produce the disease it is trying to prevent. If the virus in question is particularly deadly (such as rabies), it is not worth taking any chances with a live virus vaccine even for superior immunity.

[Back to Top of Page]



Recombinant vaccines represent the very cutting edge of vaccine technology in both veterinary and human medicine. For generations, we classified vaccines as either "killed" or "modified live" (see above). With the advent of genetic engineering, there are now new vaccines that do not fit this classification: the "recombinant vaccines." While the USDA recognizes four categories of recombinant vaccines, only the "Vectored Virus" Category is commercially available for pets.

With Vectored Virus vaccines, the viral DNA responsible for stimulating the patient's immune system is cloned into a live harmless virus. The harmless virus is injected into the patient where it travels innocuously within the body stimulating the patient's immune system to respond to the cloned viral DNA. In this way, the benefits of a live vaccine can be realized for a virus that is normally considered too dangerous for a modified live vaccine. Presently, recombinant vaccines are available for feline rabies, feline leukemia, Lyme disease, and canine distemper.

So are these vaccines better than the traditional ones? The chief benefit seems to be the reduction in vaccine reactions since there are less extraneous proteins to cause unnecessary immune stimulation when compared to killed virus vaccines. Since the virus used in recombinant vaccines is alive, there is no potentially harmful adjuvant included in the product (see below). There is also a zero chance of the vaccine virus reverting to virulence and causing infection.

(original graphic by

[Back to Top of Page]


There are several reasons why a pet might get sick from a disease it is vaccinated against. Not every pet is able to respond to vaccination due to inherent individual immunological issues. Some vaccines are not intended to prevent infection but are intended to blunt the symptoms of the disease should infection occur (as with the feline upper respiratory infections).

In most cases, the pet got sick because of incomplete vaccination. This situation generally involves a puppy that did not finish its puppy series of shots or got exposed to infection before the shot series could be completed. True vaccination breaks are extremely rare but if you think your pet may have experienced one, your veterinarian will need to issue a report to the manufacturer.

[Back to Top of Page]



It is important that live vaccines (see above) NOT be used in pregnant pets. This is because a "modified" virus that will not cause illness in the mother, may still be strong enough to infect the unborn puppies or kittens. Killed vaccines may be given during pregnancy though, as a general rule, it is best not to give any medical treatments during pregnancy if it can be avoided. While the administration of killed vaccines is commonly performed in large animals and food animals, it is not routine for dogs or cats.

[Back to Top of Page]



It is physically possible to give vaccines yourself if you know how to give a subcutaneous injection. In many areas, pet vaccines are considered "over-the-counter" medications and you can get them from your local pharmacy or by mail order. We do not recommend this practice for the following reasons:


  • It may be difficult for you to properly dispose of the needles. (In California, it is illegal to dispose of needles in the regular trash, for example.).
  • If there is any type of acute allergic reaction, you will not be prepared to address it.
  • In cats, there are specific guidelines regarding where vaccines should be placed. This makes the process trickier, especially with uncooperative cats. You may get bitten. It is also very important to know where to give each type of vaccine, as giving multiple vaccines in the same area causes increased inflammation, which can lead to vaccine-site tumor formation.
  • You may not have kept proper records of vaccination should proof of vaccination be needed. Facilities requiring proof of vaccination may be unwilling to accept your own word that your pet is vaccinated adequately.
  • Modified live vaccines are somewhat sensitive to proper storage. They cannot be mixed up in advance and their components must be kept at the proper temperature. This may be difficult depending on how vaccine is transported to your home.

If you are looking for a low cost method of vaccination, we suggest a low cost vaccination clinic rather than trying to give vaccine on your own.

[Back to Top of Page]



An adjuvant is a material added to a killed vaccine to assist in the generation of immunity. When a killed vaccine is injected, the body recognizes that a foreign substance is present and begins to break it down and remove it. If this process happens too quickly, the viral proteins will not be present long enough to generate an immunological response. Adjuvants help hold the killed virus in place and stabilize it so that its presence can be prolonged and provide a more complete stimulation of the patient's immune system.

Adjuvants have become controversial in cats especially and may be associated with tumor (especially fibrosarcoma) formation. It appears to be desirable to avoid the use of adjuvanted vaccines in cats. Neither modified live nor recombinant vaccines employ adjuvants.

[Back to Top of Page]



The feline leukemia virus has potential to be latent in a carrier cat without any signs of illness and this carrier state can persist for years. During this time, the cat is contagious and at risk for numerous problems. Many people want to skip the test to save money but, in fact, it is of great importance to know if a cat is harboring this infection. Knowing that a cat is positive allows one to save money by not unnecessarily vaccinating for feline leukemia. Further, if an owner is aware of a cat's positive status, the pet can be kept away from other cats thus preventing the spread of the disease. An owner can prepare financially for expected treatments needed for this cat if the owner is aware of the positive test. We feel strongly that testing is very important whenever one obtains a new cat as a pet.

(original graphic by

For more information of the Feline Leukemia Virus click here.

[Back to Top of Page]



Antibody levels against certain infections can be measured in a patient's blood sample. These antibody levels are called "titers." The idea is to measure a titer and determine whether or not a patient is protected against the infection in question so that unnecessary vaccination can be avoided. There is some controversy associated with this procedure:

(Photocredit: CDC Public Health Image Library)

  • Blood testing ("titering") is frequently more expensive than simply getting the vaccines in question.
  • Blood testing is only available for a few infections.
  • Antibody levels are only a small piece of the protection puzzle and it may not be correct to say that a certain antibody level "equals" protection.
  • Risks associated with giving vaccines to patients that are already protected are not clearly defined. Exactly what the risks are or if there are risks at all has not been determined.

Titering is available at many hospitals and if you are concerned about whether your pet is already protected, you should ask your veterinarian about titering.

[Back to Top of Page]



Some muscle soreness, lethargy and mild fever persisting for a day or two are considered common (normal) reactions to stimulation of the immune system. Occasionally a firm swelling temporarily develops at a vaccine site (especially with killed vaccines). Vaccine reactions beyond this are unusual but possible. Allergic reactions characterized usually by facial swelling and hives are a strong sign that special care should be taken in administering vaccinations. Vomiting can be a sign of impending shock and should be taken seriously after vaccination. Since allergic reactions potentially can become worse with each episode, it is important to take heed of these signs as severe reactions can result in shock or even death

Click here for more information on allergic reactions to vaccines.

Another reaction that has received tremendous press lately is the vaccine-induced fibrosarcoma, a form of cancer in the cat. See the next question.

[Back to Top of Page]



The fibrosarcoma is an especially aggressive form of cancer that can affect cats spontaneously or by viral induction via the feline sarcoma virus. Recently, fibrosarcomas have been removed from areas of the body typically used for vaccination and, to the surprise of the veterinary profession, particles of aluminum based vaccine ingredients (called "adjuvants") were discovered within the tumor. The working theory is that vaccination may induce this form of cancer in rare cases (between 1 in 1000 & 1 in 10,000 cats). The killed feline leukemia vaccine and the killed rabies vaccine have been implicated as being more likely to be involved. The problem is definitely not a matter of simply changing to non-aluminum based adjuvants but is more complicated. A list of preventive measures has been issued by most veterinary associations.


Click here for more information on this problem.

[Back to Top of Page]



As mentioned, in the mid-1990’s recommendations for annual canine distemper and feline distemper vaccination shifted to every three years for these vaccines. The reason for this is not that annual vaccination was found to be harmful; it simply became accepted as unnecessary.

Many people have speculated that annual vaccination is responsible for cancer, immune-mediated diseases, kidney disease, and most common ailments of senior dogs and cats. So far, there is no clear evidence that annual vaccination has increased the incidence of any specific health problems.

[Back to Top of Page]



Vaccination is an important part of a pet's health and it is should not be skipped over. If cost is a problem there are several approaches one may take but each has advantages and disadvantages.

OPTION ONE: Omit the Examination and Choose Vaccination Only

Prices vary tremendously from veterinarian to veterinarian. Some veterinarians are not comfortable administering vaccinations without completely examining the pet first. Others allow you the option of coming in for "vaccination only." Annual examination is recommended as part of basic care for any pet. The physical examination not only involves a professional assessment of the pet's condition but it is your opportunity to learn about what new products, technology or services are available that you might otherwise never hear about. The importance of this cannot be over-emphasized but if vaccinations are needed, they may not need to be given in conjunction with a complete examination. In some states, "vaccination only" is not an option or there may be restrictions.

OPTION TWO: Vaccinating Your Pets Yourself

In most states, vaccines are available over-the-counter at the regular pharmacy at substantial savings. Of course, this presupposes that you know how to administer the subcutaneous needle and that you are comfortable disposing of the the syringe. Many people find it worth it to pay more for a trained professional to administer the shot but if you have the training, this is an option that can save you money.

OPTION THREE: Vaccination Clinic

These clinics are springing up everywhere to provide streamlined "shots only" service. These clinics may be mobile (traveling monthly or weekly to your local feed or pet supply store) or may be located in your own regular veterinarian's office. Here are some tips on what to look for in a clinic:

  • Are they using disposable needles?
    You probably do not want to have your pet experience a needle that has been dulled on a previous patient or possibly inadequately re-sterilized.

  • Is the clinic using the latest guidelines to avoid Vaccine Induced Fibrosarcomas in cats?
    This might be a good indicator of whether the clinic is up-to-date in its quality control. For more information on prevention of Vaccine Induced Fibrosarcomas click here.

  • Do they seem simply interested in selling you the maximum number of vaccines or do they seem genuinely interested in informing you on which vaccines you do and do not need?
    Many vaccine clinics pay their staff commission for the number of vaccines sold.

  • Is your regular veterinarian's office sponsoring the clinic?
    If they are, this will solve a lot of confusion about keeping vaccine records straight at your vet's office and will avoid the confusion of getting vaccine recommendations from different veterinarians.

  • Are the vaccines already drawn up or are they mixed fresh while you are present?
    Modified live vaccines are very sensitive about storage especially after they are reconstituted. A mobile clinic must contend with the inherent difficulties of refrigeration. You do not want to use a vaccine that may have been reconstituted perhaps hours before.

OPTION FOUR: Pet Insurance

A pet insurance wellness plan will cover vaccination at least in part. Not all pet insurance companies offer wellness coverage but many do with a great deal of variability in how vaccination is covered (some cover a straight percentage of your expense, some reimburse a specific amount for vaccination services etc.) If you would like more information on how to choose a pet insurance plan click here.

[Back to Top of Page]



The Mar Vista Animal Medical Center is committed to preventive medicine for all patients. We follow the most up to date recommendations and use the highest quality vaccine products.

We normally have a low-cost vaccination clinic every Sunday from 9 AM to 11 AM. During the CoVid-19 outbreak, we have decided to offer out lower prices 7 days a week to help mitigate expense for our clients as well as to minimize crowding on Sundays. We wish all pets everywhere excellent preventive care at a reasonable cost.

Page last updated: 9/14/2022