Inactivated whole agent vaccines are characterized by which of the following?

Inactivated whole agent vaccines are characterized by being composed of killed microbes. This means that the vaccine contains the entire pathogen that has been killed or inactivated so that it cannot cause disease. These vaccines trigger an immune response without the risk of causing the disease itself, making them safe for administration.

The killed microbes in these vaccines stimulate the body's immune system to recognize and fight off the actual live pathogens if the individual is exposed in the future. This type of vaccine does not require live pathogens, which differentiates it from other vaccine types that might contain live attenuated forms of the virus or bacterium.

Other characteristics, such as the need for refrigeration, can vary depending on the specific formulation and ingredients of the vaccine and are not a defining trait of all inactivated whole agent vaccines. Therefore, the key feature of inactivated whole agent vaccines is their composition of killed microbes, allowing for a safe immune response.