Cats get colds by catching viruses from other cats, almost always through direct contact or shared living spaces. Two viruses cause the vast majority of feline upper respiratory infections: feline herpesvirus and feline calicivirus. Up to 97% of cats are exposed to herpesvirus at some point in their lives, making these infections nearly universal in the cat population.
The Two Viruses Behind Most Cat Colds
Feline herpesvirus (also called feline viral rhinotracheitis) is the more common culprit. It causes sneezing, nasal congestion, watery eyes, and fever. It can also cause ulcers on the surface of the eye. The defining feature of this virus is that it never truly goes away. Up to 80% of exposed cats develop a lifelong infection, and 100% of kittens that recover from an acute episode become chronic carriers. Of those carriers, up to 45% will periodically shed the virus, typically during periods of stress, spreading it to other cats without showing obvious symptoms themselves.
Feline calicivirus is the other major player. It produces similar upper respiratory symptoms but is more likely to cause mouth ulcers and, in some cases, can spread to the lower respiratory tract and cause pneumonia. About 10% of cats in small household settings carry calicivirus, but that number skyrockets to 90% in crowded environments like shelters and breeding facilities. Around 80% or more of cats that survive an acute calicivirus infection also become chronic carriers. In rare cases, a severe systemic form of calicivirus develops that is fatal in roughly two-thirds of affected cats.
How the Infection Spreads
The most common route is nose-to-nose contact between cats. When an infected cat sneezes, it releases virus-laden droplets that a nearby cat can inhale. Grooming each other, sharing food bowls, and sleeping in the same bed all create opportunities for transmission. This is why multi-cat households, shelters, and catteries see such high infection rates.
Indirect contact matters too. Calicivirus in particular is hardy and can survive on surfaces like food dishes, litter boxes, bedding, and even your hands and clothing. If you pet a sick cat at a friend’s house and then come home to your own cat, you can carry the virus with you. Herpesvirus is more fragile outside the body but can still survive long enough on shared objects to pose a risk.
Carrier cats are a major source of new infections. Because so many cats carry these viruses for life without looking sick, a perfectly healthy-looking cat can quietly spread the virus to others. Stress is the biggest trigger for shedding: a move to a new home, a new pet in the household, a vet visit, or even a change in routine can reactivate viral shedding in a carrier cat.
What Makes Some Cats More Vulnerable
Kittens and unvaccinated cats face the highest risk of getting sick. Their immune systems either haven’t matured or haven’t been primed by vaccination, so the virus hits harder and lasts longer.
Environmental factors play a huge role. Crowding increases the overall pathogen load in a space and the rate of contact between cats. Poor ventilation and high humidity promote the buildup of airborne pathogens and irritate the respiratory tract directly, making cats more susceptible to infection. Even noise, uncomfortable temperatures, unfamiliar people, and unpredictable handling contribute to stress, which suppresses immune function. This is why cats so often come home from shelters or boarding facilities with a cold: the combination of crowding, stress, and pathogen exposure creates ideal conditions for infection.
Can You Give Your Cat a Cold?
The typical human cold, caused by rhinoviruses, doesn’t infect cats. However, cats are susceptible to human influenza viruses. Research has confirmed that human seasonal flu strains (H1N1 and H3N2) can naturally jump from owners to their cats. In one study, about 2.8% of cats tested positive for human influenza viruses, and the transmission was linked to close contact with owners who had flu-like symptoms. So while you can’t give your cat a regular cold, you could potentially pass along the flu.
How Quickly Symptoms Appear
After exposure, symptoms typically show up within 2 to 6 days for both herpesvirus and calicivirus. In mild cases, the sneezing, runny nose, watery eyes, and low energy last about 5 to 10 days, similar to a human cold. Severe cases can drag on for up to 6 weeks, especially if a bacterial infection develops on top of the viral one.
The symptoms to watch for beyond typical cold signs include mouth ulcers (sores on the gums, tongue, or roof of the mouth that make eating painful), eye ulcers or a cloudy appearance to the eye, refusal to eat or drink, and labored breathing. Calicivirus that spreads to the lungs can cause pneumonia, and kittens in particular can deteriorate quickly.
Why Vaccines Help but Don’t Prevent Infection
The core feline vaccine (FVRCP) covers both herpesvirus and calicivirus, but it works differently than you might expect. None of the available respiratory vaccines completely prevent infection or stop a cat from becoming a carrier. What they do is significantly reduce the severity of symptoms. A vaccinated cat exposed to herpesvirus or calicivirus will generally get less sick and recover faster than an unvaccinated one. The immunity from vaccination is considered “non-sterile,” meaning the virus can still get in and establish itself, but the cat’s immune system is better prepared to fight it off.
This is why vaccination is still strongly recommended even though it isn’t a perfect shield. A mild cold is a very different experience from a severe 6-week respiratory illness with eye ulcers or pneumonia.
Living With a Carrier Cat
Because virtually all cats that recover from herpesvirus and the majority of calicivirus survivors become lifelong carriers, recurrent cold symptoms are common. Many cat owners notice their cat gets sneezy or develops watery eyes during stressful periods. Keeping your cat’s environment stable and low-stress, with consistent routines, hiding spots, and minimal disruptions, is one of the most practical things you can do to reduce flare-ups. In multi-cat homes, providing separate food and water bowls, multiple litter boxes, and enough space for each cat to retreat reduces both stress and direct transmission opportunities.