Air Force Immunizations Back-up Technician (IBT) Practice Test

Passive immunity is characterized as immediate and temporary because it involves the transfer of antibodies from one individual to another, providing instant protection without the recipient's immune system needing to mount a response. For example, maternal antibodies passed to a newborn during pregnancy or through breastfeeding exemplify this type of immunity, offering the child immediate protection against certain infections but typically lasting only a few months.

In contrast, active immunity requires exposure to a pathogen or vaccine, prompting the immune system to develop its own antibodies and memory cells. This process takes time and generally results in long-lasting protection, distinguishing it from the immediate and short-lived nature of passive immunity. Natural immunity arises from infection or illness, which also does not offer the same immediate duration as passive immunity, while long-term immunity refers to a sustained protective response that actively develops over time. Therefore, passive immunity is the most fitting choice regarding immediate and temporary protection.