Doc, another round of vaccinations, why so many?” As a puppy or kitten owner you may ask your veterinarian this very question, or may simply wonder why. Hopefully you will find this attempt to, in brief, help shed some light (although sometimes my light is dim) on this very question.
First of all, one should understand that it is not the vaccine that protects our pets from the diseases we vaccinate against. It is the body’s immunological response to the vaccines that protects them from disease. Just like all aspects with our puppies and kittens, not only are they maturing physically but their immune system continues to mature and develop after birth. Initially, your puppies and kittens are protected by diseases from their “mom.” Aren’t moms great? They pass their immunity both transplacentally and through their milk, primarily through colostrum. But this immunity passed along doesn’t last a lifetime. It will gradually decline over several weeks’ time and this is where immunizations (vaccines) come into play.
Most puppies and kittens are protected for the first few weeks of life, say through about 6-8 weeks, by the maternal protection passed along to them. However, the mother needs to have been properly immunized and up to date as well. Another caveat that can comes into play with immune protection is did the “youngsters” nurse properly when born and how healthy was the mother’s immune system to start with? Keep in mind some adult moms may not have had good protection to start with and thus are not passing this protection along to their offspring.
Most veterinarians typically recommend starting puppy and kitten vaccinations somewhere between the ages of 6-9 weeks of age. Your puppy’s and kitten’s lifestyle, age, breed and size will help to determine what initial vaccines are recommended initially along with the “booster” vaccines to follow. Booster vaccines are then recommended typically every 3-4 weeks thereafter to finish out somewhere around 15-18 weeks of age. Again, this may vary somewhat depending on the vaccine itself and the breed and lifestyle of your pet. So, back to your question, “why so many vaccines?”
As the puppy’s and kitten’s immune system develops with age, it is better able to respond to the vaccines it receives. With the initial vaccines received by puppies and kittens, the immunity passed along by its mother may recognize the vaccine as the disease and render it inactive and the puppy or kitten’s own immune system is too underdeveloped to respond to the vaccine. Good news in this scenario is puppy/kitten is still protected by “mom,” but the vaccine didn’t do much good this time. This same scenario will continue with each successive vaccine. However, at some point, mom’s passed along immunity is lost and the puppy’s or kitten’s immunity is developed enough to give an adequate response to the vaccine.
The challenge with all of this is the time frame for both “mom’s” decline in immunity passed along and the puppy’s or kitten’s immune system developing. This varies between each litter and can be influenced by breed, environment, stress and several other factors. Unfortunately, we as veterinarians can’t exactly predict when this will occur. What we do know is based on statistics: in most puppies and kittens, this “cross-over” point (mom’s immunity gone and youngster’s immunity developed) occurs around 12 weeks of age or so. However, sometimes this can occur at an earlier age or an older age. Hence the answer to your question, we vaccinate in a series because we don’t know exactly when this “cross-over” point will occur with your puppy or kitten. After your puppy’s or kitten’s series of immunizations, the next vaccines are typically due one year later and thereafter booster “shots” will vary based on what vaccines are deemed necessary.
Vaccines are very important as a part of your puppy’s and kitten’s total health package. Get them started off on the “right paw” with a proper health program that will include immunizations. Though at first it may seem like a lot of visits, it will not only help to ensure the health of your new “cutie” but also help with socialization.