Community Health Nursing Practice Exam

What type of immunity is demonstrated when individuals exposed to a disease do not develop it due to prior vaccination?

1. Herd immunity.

2. Passive immunity.

3. Cross-immunity.

4. Active immunity.

The correct answer is: Cross-immunity.

The situation described is a classic example of active immunity. This type of immunity occurs when an individual's immune system is exposed to a pathogen, either through infection or vaccination, and subsequently produces a response by generating specific antibodies against that pathogen. When someone receives a vaccine, they are essentially being introduced to a harmless component of the virus or bacteria, which prompts the immune system to create a memory of it. Consequently, if the individual later encounters the actual disease, their immune system is prepared to fight it off effectively, often preventing the disease from developing. In this scenario, the focus is on the individual's immune response that develops as a result of their prior vaccination. This distinguishes active immunity from other forms, such as passive immunity, where antibodies are transferred from one person to another (e.g., from mother to baby). While herd immunity involves a population-level effect of widespread vaccination, maintaining community protection against an outbreak, it doesn’t specifically apply to the individual response highlighted in the question. Cross-immunity refers to immunity to one pathogen that provides partial protection against a related pathogen, which is not the main focus here.