2013 World Small Animal Veterinary Association VACCINATION GUIDELINES FOR NEW puppy OWNERS http://www.wsava.org/sites/default/f...May%202013.pdf
" 2. The WSAVA also states that the last puppy vaccine against the core diseases should be given at 14-16 weeks of age. This is because, before this time, the mother passes immunity to her puppies, and this ‘maternal immunity’ can prevent the vaccine from working.
3. A high percentage (98%) of core puppy vaccines given between 14-16 weeks of age will provide immunity against parvovirus, distemper and adenovirus for many years, and probably for the life of the animal
6. The WSAVA supports the use of titre testing. ...."