Introduction When the immune system is weakened—such as by HIV, certain cancers, or immunosuppressive medications—the body becomes more vulnerable to infections that a healthy immune system would typically fight off. These are referred to as opportunistic infections (OIs). For people living with HIV, especially those with a low CD4 count, OIs can lead to serious illness or even death if not prevented or treated early. The good news is that most OIs are preventable through medication, routine screenings, and healthy habits. This article explores the most common OIs, who is at risk, and practical strategies to prevent them. What Are…