[brunie's mom]

I found this bit of an article about Puppy Immunity. Also Dr. Dodd recommends first vaccines for a puppy at 9-10 weeks not before....and that is what is being taught at all of the Veterinary Schools in the U.S.

Window of susceptibility

The age at which puppies and kittens can effectively be immunized is proportional to the amount of antibody protection the young animals received from their mother. High levels of maternal antibodies present in a puppy's or kitten's bloodstream will block the effectiveness of a vaccine. When the maternal antibodies drop to a low enough level in the puppy or kitten, immunity (protection from disease) can be produced through vaccination.

The antibodies from the mother generally circulate in the newborn's blood for a number of weeks. There is a period of time from several days to several weeks in which the maternal antibodies are too low to provide protection against the disease, but too high to allow a vaccine to work. This period is called the window of susceptibility. This is the time when despite being vaccinated, a puppy or kitten can still contract the disease.

The length and timing of the window of susceptibility is different in every litter, and even between individuals in a litter. A study of a cross section of different puppies showed that the age at which they were able to respond to a vaccine and develop protection (become immunized) covered a wide period of time. At six weeks of age, 25% of the puppies could be immunized. At 9 weeks, 40% of the puppies were able to respond to the vaccine and were protected. The number increased to 60% by 16 weeks, and by 18 weeks, 95% of the puppies could be immunized.

As you can see, it is really impossible for us to determine, when in the presence of passive immunity, an individual puppy or kitten should be vaccinated. There are just too many variables. Even if we did blood tests on them, each animal in the litter would probably have a different titer. Some will have absorbed more antibodies, the antibodies may have broken down more quickly in others, or some may have used a portion of their antibodies if they encountered harmful bacteria or viruses. Additionally, a young animal may have a protective titer (level of antibodies) for one disease, but not enough for another.

Progress is being made. Some of the newer vaccines can stimulate active immunity in the young animal even when maternal antibodies are present. These are called 'high titer, low passage vaccines.' These modified live vaccines contain a higher number of virus particles (high titer) which are less attenuated (low passage) than the 'average' vaccine. High titer, low passage vaccines can generally elicit an immune system response in young animals who have a maternal antibody level that would prevent them from responding to an 'average' vaccine. A common way to describe this is "the vaccine 'breaks through' the maternal antibody." This vaccine technology is used most often with parvovirus. As vaccines improve, we will hopefully be better able to protect puppies and kittens throughout their early life.


References and Further Reading


Al-Sarraf, R. Update on feline vaccine-associated fibrosarcomas. Veterinary Medicine. 1998;729-35.

American Association of Feline Practitioners/Academy of Feline Medicine. Recommendations for Feline Leukemia Virus Testing. The Compendium on Continuing Education for the Practicing Veterinarian. 1997;1105-7.

Bell, FW. Recommendations for FeLV- and FIV-positive cats with cancer. In August, JR (ed.) Consultations in Feline Internal Medicine. W.B. Saunders Co. Philadelphia, PA; 1997;572-8.

Bergman, PJ; Couto, CG; Hendrick, MJ; Macy, DW; Richards, JR; Starr, RM (contributors). Vaccine-associated feline sarcoma symposium. Sponsored by the Vaccine-Associated Feline Sarcoma Task Force and the Arm & Hammer Division of Church & Swight Co., Inc. July 25, 1998.

Brakeman, L (ed.) Researchers suspect genetic cause for vaccine site sarcomas. dvm 1998; July 1, 41-45.

Cole, R. Rethinking canine vaccinations. Veterinary Forum; 1998; Jan;52-7.

Greene, CE. Immunoprophylaxis and immunotherapy. In Greene, CE (ed.) Infectious Diseases of the Dog and Cat. W.B. Saunders Co. Philadelphia, PA; 1998;717-750.

Jarrett, O. Development of vaccines against feline leukemia virus. In Kirk, RW; Bonagura, JD (eds.) Current Veterinary Therapy XI. W.B. Saunders Co. Philadelphia, PA; 1992;457-60.

Pfizer Animal Health. Duration of immunity in companion animals after natural infection and vaccination. Pfizer Animal Health; June 30, 1998.

Roitt, I; Brostoff, J; Male, D. Immunology. CV Mosby Company. St. Louis, MO; 1985.

Rosen, DK. Feline infectious diseases and rational vaccine protocols for immunization. Presented at the Wisconsin Veterinary Medical Association Convention. October 10, 1998.

Schultz, RD. Current and future canine and feline vaccination programs. Veterinary Medicine. 1998;233-253.

Tizard, I; Yawei, N. Use of serologic testing to assess immune status of companion animals. Journal of the American Veterinary Medical Association. 1998;213;54-60.

Veterinary Learning Systems. Recombinant vaccine technology. Supplement to The Compendium on Continuing Education for the Practicing Veterinarian. 1997;19(2).

Veterinary Learning Systems. Vaccine technology in the 21st century. Supplement to The Compendium on Continuing Education for the Practicing Veterinarian. 1998;20(8c).

Gina