Vaccination guidelines are designed to be exactly that: guidelines. There is no one-size-fits-all vaccination schedule. They are intended to be tailored to each individual cat, taking into account factors such as lifestyle, exposure risk, and individual circumstances.
The American Animal Hospital Association (AAHA) and American Association of Feline Practitioners (AAFP) say it best in their 2020 AAHA/AAFP Feline Vaccination Guidelines:
“One vaccination plan or protocol cannot be applied to every cat.”
At Nautilus Persians, we have used those guidelines as a blueprint to create a vaccination schedule that makes sense for the kittens we raise.
For us, that schedule is simple:
12 weeks. 16 weeks. 26 weeks.
Here is why.
12 Weeks
We give our kittens their first FVRCP vaccine at 12 weeks because we are balancing two things: maternal antibodies and exposure risk.
Maternally Derived Antibodies (MDA):
MDA are antibodies passed from a queen to her kittens through her colostrum. While these antibodies help protect young kittens, they can also interfere with a vaccine's ability to produce an immune response.
How long that interference lasts varies from kitten to kitten. It depends on several factors, including the queen's immune status and how much colostrum each individual kitten receives.
Studies have found that some kittens may still have enough MDA to interfere with vaccination surprisingly late. In fact, AAHA/AAFP notes that studies suggest up to one-third of kittens may fail to respond to a final core vaccine at 16 weeks, with blocking MDA potentially persisting to 20 weeks.
Exposure Risk:
AAHA/AAFP notes that vaccination decisions should be based on a risk-benefit assessment that considers, among other things, a cat's likelihood of exposure.
For our kittens, exposure risk during their first 12 weeks is very low. They are raised in our home, with their mother, in a closed and controlled environment.
And when we say closed, we mean closed. We do not allow visitors—even family and friends—around unvaccinated kittens. We also do not take our cats to shows while we have unvaccinated kittens at home. We intentionally limit opportunities for disease to enter the cattery during this vulnerable period.
At around 12 weeks, that risk begins to change as kittens prepare to leave our home and enter the wider world.
That makes 12 weeks our sweet spot: MDA is more likely to have waned, just as exposure risk begins to increase.
16 Weeks
Our kittens receive their second FVRCP vaccine at 16 weeks, four weeks after their first.
Why four weeks? It falls within the recommended 3–4 week interval between vaccinations.
If MDA interfered with the vaccine given at 12 weeks, those antibodies have had another four weeks to decline, giving the 16-week vaccine another opportunity to produce a successful immune response.
Simple as that.
26 Weeks
Our kittens receive another FVRCP vaccine at approximately 26 weeks of age.
Why? Because 16 weeks isn't a magic number.
As mentioned earlier, studies suggest up to one-third of kittens may fail to respond to a final core vaccine at 16 weeks, with blocking MDA potentially persisting to 20 weeks.
Revaccinating at approximately six months helps reduce this potential window of susceptibility by providing another opportunity for successful immunization after MDA has declined.
After the 26-week vaccine, if there is still any doubt that a kitten has seroconverted, antibody titer testing can be considered—especially before taking a kitten into a very high-risk environment, such as a show hall.
Finding the Right Balance
Our 12, 16, 26 schedule makes sense for most of the kittens we raise, but that doesn't mean it makes sense for every kitten.
The guidelines explain that a kitten in a shelter, rescue, high-traffic cattery, or other high-exposure environment may benefit from beginning vaccination much earlier. A kitten who received little or no colostrum may also have a very different level of maternal antibodies.
Within our own program, we reevaluate our schedule when circumstances change. If a kitten fails to receive colostrum from its mother, we may consider beginning respiratory protection with an intranasal vaccine as early as four weeks. If we have a known URI outbreak in the cattery, we may choose to vaccinate before 12 weeks.
There is no single vaccination schedule that is right for every kitten.
The goal is to balance maternal immunity, exposure risk, and the individual kitten to provide protection when they need it most.
For the average Nautilus Persian kitten, 12, 16, and 26 makes sense.