Final answer:
The age of a person affects their susceptibility to infection due to the decline in immune system functioning as people get older. Young children and older individuals with weakened immune systems are particularly susceptible. Thymic involution and other factors contribute to the age-related decline in immune function.
Step-by-step explanation:
The age of a person affects their susceptibility to infection due to a natural decline in immune system functioning as people get older. This decline, known as immunosenescence, typically begins around age 50 and worsens with increasing age. Older individuals are generally more susceptible to diseases compared to younger individuals.
Young children under the age of 5 also have a higher susceptibility to infections due to their immune systems not yet being fully developed. On the other hand, individuals with weakened immune systems, whether due to aging or an unrelated illness, are more susceptible to certain infections compared to individuals with stronger immune systems.
The age-related decline in immune function is caused by various factors, including thymic involution, which is the shrinking of the thymus gland that occurs throughout a person's life. Understanding how age affects immunity is crucial in treating and managing the health of the aging population.