This puppy should just be
beginning his vaccinations in three weeks, not completing them. Puppies get immunities from their mother through nursing which attack and kill the viruses in the vaccinations if given too soon.
In one study of a cross section of different puppies the age at which they were able to respond to a vaccine and develop protection covered a wide period of time. At six weeks of age, 25% of the puppies could be immunized. At 9 weeks of age, 40% of the puppies were able to respond to the vaccine. The number increased to 60% by 16 weeks, and by 18 weeks of age, 95% of the puppies could be immunized. Parvovirus: Serious Diarrhea in Puppies & Dogs
This is the vaccination protocol that has been adopted by most vet schools. 9-10 weeks is the recommended age to start vaccinations.
W Jean Dodds Vaccine Protocol VACCINATION PROTOCOLS