A Review by Dr. Michael W. Fox

“Anytime you inject anything into a patient you have the potential of killing them”.—Prof. Ron Schultz, DVM.

The practice of giving dogs several different vaccinations against various diseases all at the same time early in life and then again every year as "boosters" for the rest of their lives is coming to a close. This is for two primary reasons: animals can have adverse reactions to vaccinations that can impair their health for the rest of their lives; routine "booster" shots are not needed since earlier vaccinations have given animals sufficient immunity to the diseases in question.

First, puppies should not be given vaccinations before 8-10 weeks of age since this can interfere with the natural immunity in their systems conferred by the colostrum or first milk of their mothers. But if the immune status of the mother is unknown, as is the situation for many to-be-adopted pups in animal shelters, vaccinations at an earlier age between 5-6 weeks is the usual protocol. Adult animals in a compromised immune state, as for example those who are ill, injured, or being given an anesthetic and operated on, such as being spayed or castrated, or for any other surgical procedure, are pregnant or nursing, or are old and infirm, should not be vaccinated.

Rabies vaccinations, unless in-field conditions make this logistically difficult, should never be given at the same time other combined vaccinations are given. Separate by at least 3 weeks.

Dr. Dodds is an internationally recognized authority in veterinary hematology and immunology and has done extensive research and developed a minimal protocol for vaccinations as follows.  This is not to mean that other protocols recommended by a veterinarian would be less satisfactory.  It is a matter of professional judgement and choice.

Age of Pups  - Vaccine Type

  • 9-10 weeks - Distemper + parvovirus, MLV (e.g. Intervet Progsrd Puppy DPV)14 weeks - Same as above 
  • 16-18 weeks - (optional) Same as above
  • 20 weeks or older - if allowable by law Rabies
  • 1 year - Distemper + Parvovirus, MLV
  • 1 year - (give 3-4 weeks apart from distemper/parvovirus booster) Rabies, killed 3-year product

Studies have shown that in normal, healthy dogs at the time of vaccination, Parvovirus vaccines are good for 7 years, Rabies vaccines for 3-7 years, Distemper vaccines for 5-15 years (depending on the strain), and Adenovirus 2 vaccines for 7-9 years. Prof. Ron Schultz recommends using Merial’s 3-way combo; parvo, distemper and CAV2/hepatitis as the only relatively safe combination of vaccines.

If your dog received all core vaccines by 16 weeks of age, have antibody blood titers evaluated at 1 year of age if you have reservations about re-vaccination.

Corona virus and giardia vaccinations for dogs are not recommended.
For dogs at risk, Leptospirosis vaccine (the four-serovar product of Fort Dodge being preferred) should be given at 12 and 15 weeks and repeated one year later. It only confers protection, however, for 3-4 months, so repeated vaccinations are called for with dogs with significant exposure risk.

Lyme vaccine should be given to at-risk dogs but the bacterium vaccine can cause immune-complex disease so Merial’s recombinant Lyme vaccine is preferred. Again, blood serum titers should be taken to assess dog's immune status where there is doubt, rather than simply giving booster shots.

Neither Lyme disease vaccinations, that give highly unreliable protection, nor leptospirosis vaccinations should be given close to the time that any other vaccinations are given.

No vaccine can guarantee immunity, since different strains of infective agents may be involved, and animals who are stressed, suffering from poor nutrition, genetic susceptibility and concurrent disease may have impaired immune systems and lowered resistance to disease. But this does not mean that they should never be vaccinated or be routinely re-vaccinated just in case, because vaccinations can cause further immune system impairment and a host of health problems---the so called vaccinosis diseases--- that these new vaccination protocols are aimed at minimizing.


I would like to make you aware that all 27 veterinary schools in North America are in the process of changing their protocols for vaccinating dogs and cats.


The first point to consider is safety.  Vaccines can be harmful and we should be vaccinating because the advantages outweigh the risks.


Dogs and cats immune systems mature fully at 6 months. If a modified live virus vaccine is given after 6 months of age, it produces immunity, which is good for the life of the pet (ie: canine distemper, parvo,feline distemper).

Links & Suggested Reading

Dr.  Jean Dodds

Duration of Immunity

Dr Richard Pitcairn

Importance of Vaccinations