For most children, vaccination against HFMD is most appropriate before the age of 5 years, because the immune function of children is often not well developed before the age of 5 years, and they are easily infected with intestinal viruses, such as coxsackievirus or EV71 virus, which can cause HFMD, which can lead to herpes on the hands, feet, mouth and buttocks. In particular, children with enterovirus EV71 can develop severe HFMD and even myocarditis and encephalitis, and it is best to vaccinate children against enterovirus EV71 at this time.