Chemoprophylaxis is defined as

• A. The prevention of disease by the administration of vaccines.
• B. The administration of medicines to treat a person.
• C. Place higher loads on the muscle, tendons, ligaments, and joints.
• D. Visual clues

Answer: (B)

Using medicines to prevent disease in someone who is at risk is what chemoprophylaxis is all about. It focuses on preventing infection before it starts, rather than treating an illness that has already appeared. This is different from vaccines, which use a biological agent to train the immune system (immunoprophylaxis), and from treatment, which aims to cure or manage an active disease. So the idea is proactive protection with drugs, such as taking antimalarials to prevent malaria when traveling to risk areas, or using antibiotics after a known exposure to reduce the chance of infection. The option that mentions medicines describes treatment rather than prevention, which is why it doesn’t fit chemoprophylaxis.