Final answer:
Vaccines for pets are categorized as core or non-core, and modern subunit vaccines are designed by selecting antigenic components of pathogens to effectively induce immunity with reduced risk of side effects.
Step-by-step explanation:
Vaccines for dogs and cats have been divided into core and non-core vaccines to facilitate vaccine selection. Core vaccines are those recommended for all pets, while non-core vaccines are given depending on the animal's exposure risk. Among the modern approaches in vaccine development is the use of subunit vaccines, which are made from selecting a specific component of an organism that is antigenic, such as a viral capsid protein or a polysaccharide.
These immunogenic components create an immune response in the body against the disease-causing organism. Subunit vaccines are advantageous because they can be produced through genetic engineering and biotechnology, leading to vaccines that are safe, effective, and cost-efficient. Live attenuated vaccines, inactivated vaccines, subunit vaccines, toxoid vaccines, and conjugate vaccines are different types of vaccines, each working by exposing the immune system to components or whole pathogens in a way that triggers an immune response without causing the disease.