Puppies and kittens have unique set of circumstances that needs to be addressed so ultimately they will be protected. Puppies and kittens are born with a pure untainted immune system, no antibodies or memory cells. If they are exposed to disease, they get sick. So in order to protect newborns, an amazing phenomenon happens. The mother’s milk contains all of her antibodies. This first milk is called colostrum. The first 24hrs of nursing, the infant’s gut will absorb these large protein molecules directly into their blood stream. After 24hrs, the milk is digested. So, it is very important for newborn puppies and kittens to nurse the first 24hrs. It is also important the mother be current on her vaccines before breeding.
So what does this maternal immunity do? It protects the puppies and kitten from all the diseases the mother is protected against. But there are two catches, it is temporary and it cannot tell the difference between vaccine pathogen and the disease pathogen. These two “catches” dictates the puppy’s and kitten’s vaccine schedules.
Statistically, 95-99% of the 6 week old puppies and kittens that nursed are protected by the maternal antibodies. At 8 weeks of age about 80-90% of the puppies and kittens are still protected by the maternal antibodies. At 12 weeks of age 10% of the puppies and kittens are protected. And by 16 weeks of age the maternal antibodies are gone. Any attempt to vaccinate puppies less than 12 weeks of age has a chance the vaccine will be neutralized by the maternal antibodies and the puppy and kitten will get no benefit.
An immune system needs stimulation from at least two injections. The first vaccine starts the process and then 3-4 weeks later the second stimulates the memory response. Then each booster rekindles the memory cells.
So how do we vaccinate puppies and kittens? The vaccine schedule is made by using the statistics of the maternal antibodies. So any vaccine given 6 weeks or earlier did not hurt the puppy or kitten but did not help the puppy or kitten either. Most veterinarians start the vaccines at 8 weeks of age, give boosters at 12 weeks of age, and finish the series at 16 weeks of age. This is the least amount of shots that ultimately stimulates the puppy’s and kitten’s immune system for a full year. Whether the puppy gets a 100 vaccines or 3 leading up to 16 weeks of age, the outcome is still the same.
Boosters are given 1 year later. Evaluating the pet’s environment and exposure dictates what vaccines to give. This is also another good time to use 3 yrs vaccines.
Rabies vaccines are handled a little different. Each municipality dictates the vaccine schedule for puppies and kittens. Rabies vaccine can be given as young as 12 weeks of age. Dogs and cats are then revaccinated 1 year later. Again, the municipality will dictate whether 1 or 3 year vaccines will be recognized. Only licensed veterinarians can give rabies vaccine to be valid.