There are a variety of factors that can contribute to someone's risk of contracting a disease. In general, those with weaker immune systems or who are otherwise immunocompromised are more at risk. This includes the elderly, young children, and those with chronic illnesses. People who live in close quarters, such as in nursing homes or prisons, are also at an increased risk, as diseases can spread more easily in these environments. Additionally, people who travel to areas where diseases are prevalent may be more likely to contract them.