What happens if a puppy is vaccinated too early?

If a puppy is vaccinated too early, the mother's antibodies can interfere with a vaccination's ability to mount the puppy's own immune response. Thus, puppies need a series of vaccinations to allow their immune system to break through waning maternal antibody. Puppies should receive their first vaccinations at six to eight weeks of age. Most vaccines are given every 2-4 weeks until actual protection is expected to be achieved. Depending on your puppy’s age, this may require 3-4 vaccinations for the Distemper/Parvo series until your puppy is 16-20 weeks of age. If your dog is over 16 weeks of age and isn’t up-to-date on shots, or if you’re not sure, your veterinarian may recommend a shorter series. The timing and interval between booster vaccinations is critical to ensure your puppy is protected. A vaccination schedule can start as early as 6-8 weeks of age.

If a puppy receives a vaccination for rabies before the maternal rabies antibodies are gone, the vaccination is blocked, and no immunity develops. The same is true for the other components of the vaccines—the temporary immunity received from the mother can interfere with all the vaccinations. If the dog has a disease that suppresses the immune system or takes immuno-suppressive medication, it will not respond. If the dog has a fever, the immune system will be so occupied with the fever that it will respond poorly to the vaccine. Ideally, vaccinations should be given shortly after the maternal antibodies are gone but before the puppy is exposed to infectious organisms. If the maternal antibodies have waned after one vaccination and the puppy is exposed to the disease-causing virus or bacterium before the next vaccination occurs, the puppy will likely develop the disease. The opposite problem can occur if a vaccine is mishandled. The vaccine can become virulent or cause the infection it is intended to prevent.