While the core vaccines parvo, distemper, adenovirus and most types of rabies vaccines have been shown to be protective for a minimum of three years (and, in some cases, for seven or more years), noncore, or optional, vaccines for bacterial diseases such as bordetella or leptospirosis dont provide long-term immunity and may need to be administered annually if your pet is at risk for those diseases. If these noncore vaccines are not given annually, immunity is lost. Dr. Schultz ...