The FIV Vaccine for Cats—What You Need to Know

You may have heard of FIV, or Feline Immunodeficiency Virus, often described as the feline version of HIV in humans. While the two viruses are not the same and FIV cannot infect people, the effects on cats can be serious.

The good news is that an FIV vaccine is available in Australia to help protect at-risk cats. Let’s look at what FIV is, how it spreads, and when vaccination might be recommended for your cat.

What Is FIV?

Feline Immunodeficiency Virus (FIV) is a slow-acting viral infection that weakens a cat’s immune system over time. This makes it harder for them to fight off everyday infections, heal from wounds or recover from illness.

While some cats with FIV can live for many years with good care, others may experience recurrent infections, dental disease, weight loss or chronic illness.

There is currently no cure for FIV, which makes prevention—through testing, management and vaccination—especially important.

How FIV Spreads

FIV is primarily spread through bite wounds, which means outdoor cats—especially unneutered males—are most at risk. It’s not easily transmitted through grooming, sharing food bowls or casual contact.

Your cat may be at risk if they:

• Roam or fight with other cats

• Live in multi-cat households where tensions can lead to biting

• Spend time outdoors unsupervised

Indoor cats, on the other hand, have very little risk of exposure.

The FIV Vaccine

The FIV vaccine helps protect cats against infection from the virus. It is not part of the standard F3 “core” vaccines, but rather a non-core (optional) vaccine recommended for cats with outdoor access or other risk factors.

The vaccine is available only in certain countries, including Australia and New Zealand—it’s not routinely used worldwide.

FIV Vaccination Schedule

Because FIV behaves differently from other cat viruses, the vaccination schedule is slightly more complex:

• Primary course: Three injections, given 2–4 weeks apart.

• Booster: One injection every 12 months after that.

If your cat has never been vaccinated before, our vets may recommend an FIV blood test first to ensure your cat is not already infected, as vaccination will not protect cats who are already FIV-positive.

How Effective Is the Vaccine?

Like all vaccines, the FIV vaccine isn’t 100% protective—but studies show it significantly reduces the risk of infection in vaccinated cats. Even in cases where infection does occur, vaccination may lessen the severity of disease.

However, because FIV is mainly spread through fights and bites, keeping your cat indoors or supervising outdoor time remains the most effective prevention strategy.

Possible Side Effects

Most cats tolerate the FIV vaccine well. Some may experience mild, temporary effects such as:

• A small lump or tenderness at the injection site

• Mild lethargy or reduced appetite for a day or two

Severe reactions are very rare. Our vets will discuss any potential risks based on your cat’s health and lifestyle.

Should Your Cat Get the FIV Vaccine?

Our vets will consider your cat’s lifestyle, age and risk level before recommending the vaccine.

It’s particularly recommended for:

• Outdoor or roaming cats

• Cats in semi-rural or suburban areas where other cats are present

• Cats new to the household if you’re unsure of their history

• Cats in multi-cat households where fighting sometimes occurs

Final Thoughts

The FIV vaccine is an important tool for protecting outdoor cats and reducing the spread of this lifelong infection. Combined with regular check-ups, desexing and responsible outdoor management, it can give your cat the best chance at a long and healthy life.

If your cat spends time outdoors or you’re unsure of their vaccination history, talk to us about FIV testing and vaccination today.