The very nature of healthcare settings makes them vulnerable to the spread of infections because they serve patients who are ill and are therefore susceptible hosts. Patients with altered immunity such as people with cancer or HIV/AIDS are at high risk for infection. Surgical patients are at risk because any incision creates a new portal of entry for pathogens. Elderly patients may have weakened immunity simply because of their age. Healthcare workers are themselves at risk of infection because of their close daily contact with patients who may harbor pathogens. Thus, infection control and breaking the chain of infection is a primary component of safe, effective patient care.