Final answer:
Unlicensed assistive personnel entering the patient's room without a mask requires immediate action to prevent the spread of meningococcal meningitis, which is highly contagious.
Step-by-step explanation:
A patient has been admitted with meningococcal meningitis. The observation by the nurse that requires action is that unlicensed assistive personnel enter the patient's room without a mask. Meningococcal meningitis is a highly contagious form of bacterial meningitis caused by Neisseria meningitidis. It can be spread from person to person through close contact, and it is crucial to follow strict infection control protocols to prevent its spread within a healthcare facility. Wearing a mask is one of the key precautions for healthcare workers and others who enter the room of a patient with meningococcal meningitis to reduce the risk of contracting and spreading the infection.