Parvovirus is probably the most common viral illness of dogs at the present time. It is much more common in puppies than it is in adult dogs. It can be very hard to successfully vaccinate a puppy for this disease because the antibody protection the puppy acquires from its mother can interfere with vaccination. It is important to vaccinate puppies every three to four weeks for this virus starting at 6 weeks of age and continuing until they are at least 16 weeks of age and preferably 20 weeks of age.

It is possible that this vaccine confers lifelong immunity once it does work but most veterinarians continue to recommend yearly vaccination for it. It seems prudent to at least get the vaccination at one year of age. Since it is combined with the other vaccines it is often easier just to give it yearly with them.