Epidemiologists are scientists who study how diseases spread and affect populations. They investigate patterns, causes, and effects of health issues in different groups of people. By analyzing data, they help identify risk factors and develop strategies to prevent outbreaks, making communities healthier. These experts often work with public health officials, hospitals, and research institutions to track diseases like the flu or COVID-19. Their findings guide policies and health programs, ensuring that resources are used effectively to protect public health and improve overall well-being.