Is hand, foot, and mouth disease (HFMD) contagious?

Hand, Foot, and Mouth Disease Transmission

Hand, foot, and mouth disease (HFMD) is highly contagious and spreads through direct contact with saliva, respiratory secretions, fluid from blisters, stool of infected persons, as well as through respiratory droplets and contaminated surfaces. 1

Causative Agents and Contagiousness

HFMD is caused by several enteroviruses, primarily:

• Coxsackievirus A16 (CV-A16)
• Enterovirus 71 (EV-A71)
• Coxsackievirus A6 (CV-A6)
• Coxsackievirus A10 (CV-A10) 1

The disease is highly contagious and can spread rapidly, particularly in:

• Childcare centers
• Kindergartens
• Schools
• Households with multiple children
• Areas with close community contact 1

Transmission Routes

HFMD spreads through multiple routes:

1. Direct contact transmission:

   • Person-to-person contact with saliva
   • Contact with respiratory secretions
   • Contact with fluid from blisters
   • Contact with stool of infected persons
   • Direct contact with an infected person's skin lesions 1

2. Indirect contact transmission:

   • Touching contaminated surfaces or objects (fomites)
   • Contact with toys, doorknobs, or other items exposed to the virus 1

3. Respiratory droplet transmission:

   • Close-range exposure to respiratory secretions from coughs or sneezes 1

Incubation Period and Contagiousness Timeline

The incubation period for HFMD is typically 3 to 10 days before symptoms appear 2. During this time and throughout the symptomatic period, infected individuals can transmit the virus to others. The disease is most contagious during the first week of illness, but the virus can remain in stool for weeks after symptoms resolve.

Clinical Manifestations

HFMD typically presents with:

• Fever
• Sore throat
• Maculopapular or vesicular eruptions on the palms and soles
• Oral ulcers 2, 3

In most cases, HFMD is self-limiting with symptoms lasting less than one week 3. However, some cases can progress to severe complications.

Prevention Measures

To prevent transmission of HFMD:

1. Hand hygiene:

   • Frequent handwashing with soap and water
   • Use alcohol-based hand sanitizers when soap and water aren't available
   • Especially important after diaper changes, using the toilet, and before eating 1

2. Environmental cleaning:

   • Disinfect frequently touched surfaces
   • Clean shared toys regularly
   • Avoid sharing utensils, cups, towels, and personal items 1

3. Respiratory etiquette:

   • Cover coughs and sneezes
   • Properly dispose of tissues 1

4. Isolation precautions:

   • Keep infected individuals home from school, daycare, or work until fever is gone and mouth sores have healed
   • Avoid close contact with infected persons 1

Special Considerations

• HFMD can affect adults as well as children, though it's more common in children 4
• Infected nails may serve as a reservoir for fungi with potential for spread to other body areas 5
• Fungal diseases are contagious and may spread to other family members if not treated 5
• Recent outbreaks have shown that HFMD can be transmitted within families, including from children to adults 4

Common Pitfalls and Caveats

• HFMD is often mistakenly considered a mild childhood disease, but recent outbreaks have shown more severe presentations and complications 2
• The disease can be confused with other rash illnesses, leading to delayed isolation measures
• Individuals may remain contagious even after symptoms resolve, particularly through fecal shedding
• Currently, there is no specific antiviral treatment or vaccine available for HFMD in clinical practice 6
• Formalin-inactivated EV-A71 vaccines have been developed in some Asian countries but do not protect against other common causative agents 7