Results: Logistic regression showed that the risk factors before patients' hospitalization include: malnutrition, not exclusive breastfeeding in the first 6 months, low maternal education, and poor care for sick children. The risk factors after patients' hospitalization include: peak temperature ≥ 39oC, with no signs of mouth ulcers, startling history, increase of leukocytosis, and EV71 as pathogen.