Updated On September 23rd, 2025
Pet's info: Cat | American Shorthair | Male | neutered | 2 years and 9 months old
Why are medicines given to dogs by weight but vaccines are one size for all?
2 Answers
Published on May 22nd, 2017
This is because the amount of antigen contained in a single vaccine dose is the amount needed to stimulate an immune response - this has nothing to do with an animal's body weight, because a Chihuahua has the same immune system as a Saint Bernard. The appropriate dose is the same for all members of a given species, which is why the dose does not vary based on size :)
1Pet Parents found this answer helpful
Published on September 27th, 2017
Hi there! This is because the vaccine dose is based on the amount of antigen needed to stimulate an immune response, which has nothing to do with the size of the animal. Vaccines are very different from drugs, in this respect! :)
1Pet Parents found this answer helpful
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