Age of Patients Affected by Hand, Foot, and Mouth Disease (HFMD)
HFMD predominantly affects young children under 5 years of age, with the highest incidence occurring in children under 3 years old. 1, 2
Primary Age Distribution
- Children under 5 years constitute the majority of HFMD cases, representing the most susceptible age group for infection 2, 3
- The peak incidence occurs in children aged 0-3 years, with a linear decline in case numbers as age increases 4
- The median age of affected children is approximately 25 months (range 4 months to 11 years), with 87% of cases occurring in children under 5 years 5
- In one recent study, the average age of affected children was 3.10 years, confirming younger children as the most vulnerable population 6
Age-Related Clinical Patterns
- Children under 10 years are the typical age range for HFMD, though the disease is most common and severe in the youngest subset 3
- The disease affects infants and young children most commonly, with lower herd immunity in this age group contributing to higher susceptibility 5
- Male children show slight preponderance (male-to-female ratio of approximately 1.3:1) across all pediatric age groups 5
Why This Age Group?
- Low herd immunity in younger children makes them particularly susceptible to enterovirus infections that cause HFMD 5
- The highly contagious nature of enteroviruses, combined with typical hygiene practices in young children (hand-to-mouth contact, sharing toys), facilitates transmission in this age group 2
- Daycare and preschool settings create ideal environments for viral spread among susceptible young children 1, 7
Important Clinical Considerations
- While rare, HFMD can occur in older children and even adults, though this represents a minority of cases 4, 3
- The disease incidence decreases progressively with increasing age beyond 3 years 4
- Approximately 27% of cases have a positive family history, indicating household transmission can affect siblings of various ages 4