Eight weeks is the youngest, but many are even waiting past that age. It has nothing to do with weight. It's because a vaccine is ineffective 98% of the time at any age less than 8 weeks. New information on vaccinations has changed what we use to believe. A mother's milk provides antibodies until 8 - 12 weeks of age, but these same antibodies also make any vaccine given worthless. That's why they have been given in a series because some shots will work on some puppies at 8 weeks (about 35%) and then another 50% or so it will work at 12 weeks and then like 99.9% will acquire immunity at 16 weeks so, technically, only one shot is needed at 16 weeks and then a booster at 1 year and 4 months. They're not even recommending routine annual boosters anymore. There's a lot of information on the web and too much to tell in a post. |