The CDC research showed that people 65 and older have the lowest risk of contracting the flu, while children have the highest chance. For children aged 0 to 17 years, the median incidence values (or attack rates) were 9.3%; for those aged 18 to 64, they were 8.8%; and for those aged 65 and over, they were 3.9%. It indicates that adults 65 and later have a higher risk of developing a symptomatic flu virus infection than children under 18.