Final answer:
Isolation is the prevention method that involves ways to prevent the spread of an existing infection.
Step-by-step explanation:
The prevention method that involves ways to prevent the spread of an existing infection is isolation. Isolation is the practice of separating individuals with contagious diseases from others to prevent the spread of the infection. This can be done by isolating the infected person in a separate room and ensuring strict protocols are followed to prevent surface and equipment contamination. Hand hygiene, vaccination, and antibiotics are methods used to prevent the initial infection, not the spread of existing ones.