When is Hand, Foot, and Mouth Disease (HFM) contagious?

When is Hand, Foot, and Mouth Disease (HFM) Contagious?

Hand, foot, and mouth disease is contagious beginning 1-2 days before symptoms appear and continues until all blisters have dried and crusted over, generally lasting 7-10 days from symptom onset. 1

Contagious Period Timeline

• The infectious period begins during the incubation period, 1-2 days before any visible symptoms develop 1
• Patients remain contagious throughout the symptomatic phase of the illness 1
• Contagiousness continues until all blisters have completely dried and crusted over 1
• The entire contagious period typically lasts 7-10 days from when symptoms first appear 1
• Viral shedding can continue in stool for several weeks after clinical symptoms resolve, potentially extending the contagious period 1, 2

Transmission Mechanisms

• HFMD spreads primarily through direct contact with:
  • Respiratory secretions and saliva 1
  • Fluid from blisters and skin lesions 1
  • Fecal-oral contamination 3
  • Respiratory droplets 3
• The causative agents are primarily enteroviruses, including:
  • Enterovirus A71 (EV-A71) 1, 4
  • Coxsackievirus A16 (CV-A16) 5
  • Coxsackievirus A6 (CV-A6) and A10 (CV-A10) as emerging causes 6

Return to School/Childcare Guidelines

• Children with HFMD should not return to school or childcare until:
  • Fever has resolved without the use of fever-reducing medications 1
  • All blisters have completely dried and crusted over 1
  • At least 7 days have passed since symptom onset 1
• Returning too early can trigger outbreaks in childcare or school settings 1

Prevention of Transmission

• Practice thorough handwashing with soap and water (alcohol-based sanitizers are insufficient against enteroviruses) 1
• Avoid close contact with others during the contagious period 1
• Properly dispose of tissues containing nasal secretions 1
• Disinfect potentially contaminated surfaces and objects, as enteroviruses can remain viable on surfaces for up to 28 days 1, 3

Common Pitfalls to Avoid

• Relying solely on fever resolution as an indicator that the child is no longer contagious 1
• Inadequate hand hygiene practices that don't effectively eliminate enteroviruses 1
• Overlooking environmental cleaning and disinfection of shared surfaces and objects 1
• Allowing children to return to group settings before the full contagious period has ended 1

Special Considerations

• Healthcare workers and childcare providers should follow strict infection control protocols to prevent transmission 1
• Outbreaks commonly occur in spring through fall in North America 3
• Most cases occur in children under 10 years of age, though adults can also be affected 3, 2
• In rare cases, HFMD can lead to neurological or cardiopulmonary complications, particularly with EV-A71 infections 4, 2