Epidemics refer to the rapid spread of infectious diseases within a specific population or geographic area. They can occur when a new strain of a virus, such as COVID-19, emerges, leading to widespread illness and requiring public health interventions to control the outbreak. The impact of epidemics can be profound, affecting not only health but also economies and social structures. Historical examples include the Spanish Flu of 1918 and the HIV/AIDS crisis, both of which reshaped public health policies and awareness around disease prevention and management.