Vaccine FAQ and General Information
Why Do Baby Animals Need a Series of Shots and How Many do they Need?
When a baby kitten 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 specific 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 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.
How long this maternal antibody lasts in a given 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 16 to 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 kitten’s system, any vaccines given will be inactivated. Vaccines will not be able to "take" until maternal antibody has sufficiently dropped. 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 3 to 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 3 to 4 weeks prior.
If a Vaccine Lasts a Person His or Her Whole Life, Why Do I have to Vaccinate My Pet Annually?
In this country, 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 and it is not generally done. We know most vaccines last at least one year and have not been willing to take a chance on whether they might last longer without knowing for sure.
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-1990s most veterinary teaching hospitals have restructured their vaccination policies to increase the duration of some vaccines from one year to three years. Many private veterinarians are following those guidelines for these vaccines. The important thing to realize is that this kind of extension is not possible in all situations or for all vaccines.
What Vaccines Should I get for my Pet?
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 in the home situation, etc. The best advice is to find a veterinarian that you trust and go with their recommendations.
What Vaccines Should I get if my Pet is Indoors almost Completely?
Both the American Association of Feline Practitioners and the American Animal Hospital Association have published guidelines for vaccination. Vaccinations are divided into “core” vaccines that every pet should have, and “non-core” vaccines that a pet should have depending on exposure risk.
For cats, core vaccines are the basic distemper shot (FVRCP) and rabies vaccine. Many people are surprised that rabies is a core vaccine and is considered important even for indoor-only cats but when you consider 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.
What is the Difference Between a Live and a Killed Vaccine?
These terms apply to vaccine against viral infection.
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 are injected into the patient. They filter into the immune system and 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. By using live virus, a more natural stimulation is obtained as the live viruses follow through the same steps of replication that the real virus would.
Which method is best remains somewhat controversial. Some experts feel that killed vaccine is best as there will never be a chance that the patient can contract the actual disease from the vaccine if a killed vaccine is used. Proponents of live vaccines have been able to demonstrate that far stronger immunity can be generated by the live vaccines.
Can I Give Vaccines Myself?
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.
- 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. If you do not know where to give each type of vaccine, you could be increasing the risk of 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.
Can Vaccines Hurt my Pet?
Some muscle soreness, lethargy and mild fever persisting for a day or two are considered common reactions to stimulation of the immune system. 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. Since allergic reactions (LINK) 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.
Another reaction that has received tremendous press lately is the vaccine-induced fibrosarcoma, a form of cancer in the cat (see the next question).
Can Vaccines Cause Cancer?
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 and 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.
Can Over-Vaccination Cause other Diseases?
As mentioned, in the mid-1990s 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.