Risk factors for hand, foot, and mouth disease and herpangina and the preventive effect of hand-washing.

BACKGROUND: Hygiene and social distancing are recommended control measures for hand, foot, and mouth disease (HFMD) and herpangina. However, empirical data to support this recommendation are limited.

METHODS: During an outbreak of HFMD and herpangina due to infection by the human enterovirus 71, we defined a case as a vesicular papular rash on the hands, feet, buttocks, or oral mucosa and onset from April 30 to June 26, 2008. We selected 176 HFMD and herpangina case-children and a stratified random sample of 201 asymptomatic control-children; frequency matched according to residency status. We administered a questionnaire to the parents about their children's exposures and hygienic behaviors.

RESULTS: Risk factors for HFMD and herpangina included playing with neighborhood children (odds ratio [OR]: 11 [95% confidence interval (CI): 6.2-17]), visiting an outpatient clinic for another reason ≤ 1 week before onset (OR: 20 [95% CI: 5.0-88]), and community exposures to crowded places (OR: 7.3 [95% CI: 4.1-13]). By using a score summarizing responses to 4 hand-washing questions, we found that 50% of the case-children and 2.5% of control-children had a poor score of 1 to 3, whereas 12% of the case-children and 78% of control-children had a good score of ≥ 7 (OR: 0.00069 [95% CI: 0.0022-0.022]) after we adjusted for residency, age, and community exposures by using logistic regression.

CONCLUSIONS: Hand-washing by preschool-aged children and their caregivers had a significant protective effect against community-acquired HFMD and herpangina from the human enterovirus 71 infection.