Feline Infectious Peritonitis (FIP): Why We Don’t Recommend the Vaccine
It’s one of the most feared diagnoses in veterinary medicine: FIP — Feline Infectious Peritonitis.
When cat owners hear those three letters, it’s usually followed by a rush of emotion: fear, confusion, and the question we hear often at PetMed of Key West Veterinary Clinic in Dubuque:
“Is there a vaccine for this?”
Technically, yes.
But it’s not that simple.
What Is FIP?
FIP is a rare but devastating disease caused by a mutation of a very common virus called feline coronavirus.
Most cats—especially kittens and cats in multi-cat environments—are exposed to feline coronavirus at some point in their lives.
In most cases:
- It causes mild gastrointestinal signs or no symptoms at all
- The immune system handles it without issue
But in a small percentage of cats, the virus mutates inside the body and becomes FIP, triggering a severe and often fatal immune response.
FIP can appear in two forms:
- Effusive (wet) form — causes fluid buildup in the abdomen or chest, leading to breathing difficulty or a swollen belly
- Non-effusive (dry) form — causes weight loss, neurological signs, eye changes, and systemic inflammation
While uncommon, FIP is heartbreaking when it occurs.
Why the FIP Vaccine Is Not Recommended
There is a vaccine available that claims to prevent FIP.
The problem is:
It has not been shown to reliably work.
Multiple studies have demonstrated limited to no real-world effectiveness, especially in the environments where FIP is most likely to occur—multi-cat households, shelters, and catteries.
There are a few key reasons for this:
- Most cats are exposed to feline coronavirus before they are old enough to be vaccinated
- FIP develops from a mutation within the individual cat, not just exposure
- The vaccine has shown inconsistent protection at best
Because of this, current veterinary guidelines do not recommend routine use of the FIP vaccine.
At PetMed, we focus on vaccines that:
- Are proven to be effective
- Provide meaningful protection
- Improve real-world outcomes
Unfortunately, the FIP vaccine does not meet those standards.
Maybe someday we’ll have a vaccine that truly works for FIP—but today is not that day.
What We Do Recommend Instead
Since vaccination is not effective, prevention focuses on reducing risk where we can.
That includes:
- Keeping cats indoors to limit exposure to infected feces and shared litterboxes
- Avoiding overcrowded environments
- Practicing good hygiene in multi-cat households
- Minimizing stress, especially in kittens
- Addressing early signs of illness promptly
It’s also important to understand:
FIP is not something caused by poor care or a mistake.
It’s an unpredictable disease that develops in a small number of cats after a very common exposure.
What About Treatment?
This is one area where things have improved.
For many years, FIP was considered almost universally fatal.
Now, antiviral treatments are available that have significantly improved outcomes in some cases.
However:
- Treatment is expensive
- Treatment courses are long (often 12+ weeks)
- Access can be limited
- It is not guaranteed to be successful in every case
While this progress is encouraging, FIP remains a serious and complex disease.
The Bottom Line
FIP is a devastating disease—but it is not prevented by vaccination.
Because the vaccine does not provide reliable protection, we do not recommend it at PetMed of Key West Veterinary Clinic.
Instead, we focus on:
- Proven vaccines that protect against real-world disease
- Early recognition of illness
- Staying current with evolving treatment options
And most importantly, helping owners make informed decisions based on solid science—not just availability.
FIP FAQs
What causes FIP in cats?
FIP is caused by a mutation of feline coronavirus inside the cat’s body.
Is FIP contagious between cats?
No. Cats spread coronavirus, but FIP itself develops internally and is not directly contagious.
Does the FIP vaccine work?
The vaccine has not been shown to provide consistent or reliable protection and is not routinely recommended.
Is FIP treatable?
There are newer antiviral treatments available, but they are expensive, require long treatment courses, and are not always successful.
Should my cat be tested for coronavirus?
Not routinely. Many healthy cats test positive for coronavirus, and most will never develop FIP.
Local Care You Can Trust
PetMed of Key West Veterinary Clinic proudly serves Dubuque, Asbury, Peosta, Epworth, Dyersville, Farley, and surrounding communities.
If you have questions about FIP, your cat’s risk, or current treatment options, we’re here to help you navigate this complex disease with clear, honest guidance.
Written by: Dr. Mackenzie Hellert
Updated 3/30/26