What is a polyvalent vaccine?

A polyvalent vaccine is designed to provide immunity against multiple diseases through a single administration. This approach is particularly advantageous in veterinary medicine and research settings where it is important to protect animals from several infectious agents simultaneously, thereby reducing the number of injections needed and streamlining the vaccination process. This can enhance compliance with vaccination schedules and reduce stress on the animals due to fewer procedures.

In contrast, a vaccine targeting a single disease refers to a monovalent vaccine, not a polyvalent one. The statement about vaccines formed from weakened pathogens describes live attenuated vaccines, which can be polyvalent but do not define them. Lastly, vaccines requiring multiple administrations are those that are typically given in a series for comprehensive immunity but are not inherently polyvalent by nature. The hallmark of a polyvalent vaccine is its capacity to address multiple pathogens in one formulation, making option C the correct choice.