The primary risks during the World Cup include the spread of highly contagious diseases such as measles, respiratory viruses, and arboviruses like dengue. Measles poses a significant threat due to its airborne transmissibility and the declining vaccination rates in the U.S. Heat-related illnesses are also a concern, particularly in humid host cities like Houston. Foodborne illnesses and norovirus outbreaks could arise from improper food handling at large gatherings. International visitors traveling between multiple venues increase the potential for disease transmission. Public health systems in host cities are scaling up efforts to mitigate these risks, but the challenges remain substantial given the scale of the event.