Young puppies are highly susceptible to certain infectious diseases and
should be vaccinated against them as soon as they are old enough to build
immunity. These diseases are distemper, infectious
hepatitis, parvovirus, parainfluenza, and
rabies. Leptospirosis, giardia, coronavirus, bordetella,
bronchiseptica, and Lyme diseasevaccinations are optional,
depending on the occurrence of these diseases in your area and your dog’s individual risk factors.
The American Animal Hospital Association (AAHA) has drawn up guidelines
categorizing vaccines as core or noncore, and these categories will be
indicated for all the vaccines described in this section. While these
guidelines suggest that puppies as young as 6 weeks may be vaccinated, most
veterinarians and breeders wait until 7 or 8 weeks of age. Also, vaccine
recommendations state that many vaccines do not need boosters beyond 12 weeks
of age, but veterinarians, particularly in endemic disease areas, may do a
final puppy vaccine at about 16 weeks.
Estrus, or heat, is the stage in a female dog's reproductive
cycle during which she becomes receptive to mating with males. At this time,
estrogen levels first increase and then sharply decrease, and mature eggs are
released from the ovaries. Ideally, your dog should be spayed before she enters
her first heat cycle.
A recombinant distemper vaccine is now available and, ideally, dogs will
receive either an MLV or a recombinant version of distemper vaccine.
The first distemper shot should be given shortly after weaning and before a
puppy is placed in his new home and is exposed to other dogs. Some
veterinarians recommend vaccinating puppies at 5 to 6 weeks of age, using a
combination canine distemper-measles-parainfluenza vaccine. The rationale for
combining distemper and measles vaccines is that a high percentage of
6-week-old puppies do not get a satisfactory response from the distemper
vaccine alone because of maternal antibodies that neutralize the distemper
antigen. The measles virus, which is quite similar to the distemper virus, can
overcome maternal antibody interference and induce partial distemper
protection. Alternatively, if maternal antibodies have actually disappeared in
the 6-week-old puppy, the distemper portion of the vaccine will induce complete
The distemper-measles vaccine should be used only once, for the first
vaccination, and only in puppies. The newer recombinant distemper vaccine seems
to overcome maternal antibodies and is now believed to be a better option than
the distemper-measles combination.
Postvaccination encephalitis has occasionally occurred when an MLV distemper
vaccine has been used in combination with a parvovirus vaccine in pups younger
than 6 to 8 weeks of age. Therefore, parvovirus vaccine should not be given
along with the first distemper vaccination in very young puppies. The
recombinant distemper vaccine is unlikely to cause encephalitis, and is
therefore recommended for young puppies.
Puppies younger than 8 to 9 weeks of age should be revaccinated every four
weeks until they are 16 weeks of age. Current recommendations are to
revaccinate at 1 year of age or in a year from the last vaccination, and then
every three years. This time period may be extended with future research data
on duration of immunity.