Riddle No. 24

[Carl]

The intruder seeks entry with nefarious intent
But the guard will do what it takes in order to prevent

The castle's key functions, the intruder seeks to disrupt
But the guard won't allow the castle to become corrupt

Before any sign of trouble, the guard was injected
Into the castle so that it would remain protected

The intruder's devious efforts to infect will fail
While the guard's mission to protect the castle will prevail

What is the castle ?
What is the intruder ?
What is the guard ?


Answers will be provided next Thursday evening after 21:00.

[Carl]

ANSWERS

The castle is the human body, the intruder is a virus, and the guard is the vaccine for the virus.