I just wanted to shed a little light on the subject of puppy and kitten vaccines. I often get asked, “Why do puppies and kittens need more than one set of shots?” The answer is antibodies. Let me explain…
Immune System, Two Arms
In order to explain this, a brief overview of the immune system is needed. The immune system is the body’s way of detecting and fighting foreign invaders (such as viruses or bacteria). This is accomplished by two arms of the immune system: innate immunity and acquired immunity. Innate barriers are just there, functioning as the physical barriers our body provides (such as skin, stomach acid, saliva, etc) and the “gatekeeper” immune cells that pretty much eat anything that moves. The acquired immune system works by “learning”. These cells recognize recognize specific foreign invaders and will stimulate the rest of the immune system to respond. So basically, the innate immune system isn’t very selective and will destroy anything it thinks poses a threat to the body while the acquired immune system is more selective and better at honing in on a particular pathogen.
Learning What To Destroy
The “learning” process of the acquired immune system is worth focusing on. When they are exposed to disease, antibodies are produced by “learning” cells and attach to disease particles. This helps the innate immune system recognize these diseases and kill them off. All antibodies are specific to that certain disease. Unfortunately, this process takes a week or two. This is why the first time your body is exposed to a particular disease, you get sick. However, there is good news in all of this! “Memory cells” stick around long after the disease is gone to keep on producing antibiodies. These cells stay in the body and help the body to “recognize” that particular invader should it ever come around again.
This is where our vaccines come in. Vaccines are formulated to help the body make these “memory cells” without ever getting sick. The theory is that if the body is ever exposed to that disease, the antibodies will already be there to fight the disease. We booster the vaccines to make sure that the body is always on the ready to fight diseases.
Puppies and Kittens
Now puppies and kittens (and all young mammals) are a special case. When they are born, their own immune system is very weak and can not fight infections on its own. However, their mother passes them her own antibodies through her milk. These antibodies help protect them from diseases as they grow up and their own immune systems begin to mature. After a time, the mother’s antibodies will diminish and the baby’s immune system is supposed to take over for itself. Exactly when this will occur is anyone’s guess, but most likely between 5-8 weeks old.
These maternal antibodies are usually helpful, but they can interfere with vaccines and the immune system response. Because they interfere and because the mom’s antibodies disappear at different times for different individuals, we have to booster the initial sets of vaccines every 2-4 weeks. Hopefully, we can stimulate the puppy’s immune system as the maternal antibodies are leaving without a lag of protection. By boostering, we are ensuring that the immune system will respond adequately. This gives them the best protection early in life when most are at highest risk for getting sick. And that is why we booster puppies and kittens!