Does a pet that never goes outside need to be vaccinated?

FAQ Question: 
Does a pet that never goes outside need to be vaccinated?
FAQ Answer: 

Even pets that live indoors can be exposed to diseases. Bacteria or viruses might be brought into the house in several ways. And your pet will go outdoors for medical appointments, and possibly for boarding. So, yes, even pets that live entirely indoors should be vaccinated in most cases. Talk with your veterinarian for more information about a vaccination program that is right for your pet's lifestyle.