Hand, foot, and mouth disease (HFMD) is almost never deadly. In the United States, the fatality rate for uncomplicated cases is between 0.06% and 0.11%, making it one of the least dangerous common childhood infections. The vast majority of cases resolve on their own within 7 to 10 days without any lasting effects.
That said, rare severe cases do occur, and certain strains of the virus carry more risk than others. Understanding what makes those cases different can help you recognize warning signs early.
What Makes Rare Cases Fatal
Deaths from HFMD are not caused by the rash, mouth sores, or fever that most people associate with the illness. They result from the virus reaching the brainstem and spinal cord, triggering a cascade of neurological and heart-lung complications. In fatal cases studied at hospitals, children typically had 3 to 5 days of fever before rapidly developing fluid in the lungs (pulmonary edema) that progressed to cardiopulmonary arrest. Despite severe inflammation in the brainstem, the outward neurological signs were often subtle. Instead, the clinical picture was dominated by sudden, rapid breathing difficulty and cardiovascular collapse.
This pattern closely resembles what happens in the most severe forms of polio, which is caused by a related virus. It’s important to stress how uncommon this is. Most children with HFMD never develop any complications at all.
The Virus Strain Matters
HFMD can be caused by several different viruses, but two are responsible for most cases: Coxsackievirus A16 and Enterovirus 71 (EV-A71). Coxsackievirus A16 tends to cause milder illness. EV-A71 is the strain linked to nearly all severe and fatal outcomes.
Between May 2008 and June 2014, China recorded roughly 10.7 million HFMD cases, with 3,046 deaths attributed to neurological and cardiopulmonary complications. The scale of that number reflects both how widespread HFMD is in parts of Asia and how the EV-A71 strain circulates more commonly in that region. In the U.S. and Europe, large outbreaks with significant fatalities are far less common, though they do occasionally occur.
Who Is Most at Risk
Children under 5 are the group most commonly affected by HFMD, and they’re also the ones most vulnerable to severe disease. Infants and toddlers have immature immune systems, which makes it harder for their bodies to contain the virus before it spreads beyond the skin and mouth.
Adults can catch HFMD too, though they often have milder symptoms or no symptoms at all. Pregnant women who contract HFMD should be aware that complications are rare but possible, depending on their medical history and how far along the pregnancy is. There’s limited evidence that the virus can, in uncommon cases, affect the fetus.
Long-Term Effects in Severe Survivors
For the small number of children who develop severe HFMD with significant brain or spinal cord involvement, lasting damage is a real possibility. A long-term follow-up study in China tracked children who survived severe cases between 2009 and 2017. Those with mild central nervous system involvement recovered fully, with no neurological problems afterward. But among children whose infections caused more serious brain complications, 50% experienced lasting neurological effects, including problems with movement and cognitive function.
Children who had typical HFMD without central nervous system involvement had no long-term issues at all. This reinforces that the disease exists on a spectrum: the overwhelming majority of cases are mild, but the rare severe end carries real consequences.
How It Spreads and How Long It’s Contagious
HFMD spreads through saliva, nasal mucus, blister fluid, and stool. People are most contagious during the first week of illness, but the virus can continue shedding for days or even weeks after symptoms disappear. Some people spread it without ever showing symptoms themselves, which is part of why outbreaks in daycares and preschools are so common.
Handwashing is the single most effective prevention measure. Cleaning surfaces, avoiding shared cups and utensils, and keeping sick children home during the first week of symptoms all reduce transmission.
Vaccines Exist but Are Limited
Three inactivated EV-A71 vaccines were approved in mainland China in 2015 and 2016, and two more were approved in Taiwan in 2023. No other countries currently use these vaccines, and no vaccine against any HFMD-related virus has received WHO approval.
The vaccines that do exist are highly effective against the most dangerous strain. Two doses provide an estimated 96% protection against EV-A71 illness within the first year, and 100% efficacy against severe EV-A71 disease and hospitalization in clinical trials. Real-world effectiveness is slightly lower but still strong: about 90% against severe cases and 84% against any EV-A71 infection. These vaccines only target EV-A71, though, so they don’t prevent HFMD caused by other virus strains. For families outside of China and Taiwan, no approved vaccine is currently available.
Signs That HFMD May Be Getting Serious
Most cases of HFMD involve a low-grade fever, small painful sores in the mouth, and a blister-like rash on the hands, feet, and sometimes buttocks. The illness is uncomfortable but self-limiting. Warning signs of a more serious course include high fever lasting more than 3 days, persistent vomiting, unusual sleepiness or irritability, rapid breathing, or difficulty walking. Any of these in a young child with HFMD warrants immediate medical evaluation, as they can signal the virus has moved beyond the skin and mouth.