How many strains of hand, foot, and mouth disease can one person contract over their lifetime?

Multiple Strains of Hand, Foot, and Mouth Disease Can Affect Individuals

A person can contract multiple different strains of hand, foot, and mouth disease (HFMD) throughout their lifetime, as the disease is caused by various enteroviruses with different serotypes that do not confer cross-immunity.

Causative Agents of HFMD

HFMD is caused by multiple enterovirus strains, with the most common being:

• Coxsackievirus A16 (CV-A16) - traditionally one of the most common causes 1
• Enterovirus A71 (EV-A71) - associated with more severe disease and higher rate of complications 2
• Coxsackievirus A6 (CV-A6) - emerging as a dominant strain in recent years 3
• Coxsackievirus A10 (CV-A10) - increasingly common in recent outbreaks 3

Recent epidemiological studies have shown a shift in the molecular epidemiology of HFMD-causing pathogens, with CV-A6 and CV-A10 causing more infections than previously observed 3.

Why Multiple Infections Are Possible

Several factors allow for multiple HFMD infections throughout a person's lifetime:

1. Serotype-specific immunity: Infection with one enterovirus strain generally provides immunity only against that specific strain, not against other enterovirus serotypes 4

2. Viral evolution and recombination: Extensive recombination events have been identified among enterovirus strains, which may contribute to faster evolution and extinction of dominant enterovirus serotypes 3

3. Changing epidemiology: The molecular epidemiology of HFMD causative agents changes over time, with different strains becoming dominant in different periods 5

4. Geographic variation: Different enterovirus strains may be more common in certain geographic areas 5

Clinical Implications

The ability to contract multiple strains of HFMD has important clinical implications:

• Individuals can experience HFMD multiple times throughout their life, particularly during childhood
• Subsequent infections may present with different clinical manifestations depending on the causative strain
• EV-A71 infections tend to be more severe and have a higher rate of complications than those caused by other viruses such as CV-A16 2
• Severe complications can include brainstem encephalitis, meningoencephalitis, acute flaccid paralysis, and pulmonary edema 3

Prevention Challenges

The diversity of HFMD-causing agents creates challenges for prevention:

• Vaccines targeting a single strain (such as the EV-A71 vaccine approved in China) provide protection only against that specific strain 4
• The simultaneous circulation of multiple pathogens and evolution of the molecular epidemiology make interventions based solely on a single agent inadequate 4
• Multi-component vaccines may be needed for comprehensive protection 5

Key Takeaways

• HFMD is caused by multiple enterovirus strains, primarily CV-A16, EV-A71, CV-A6, and CV-A10
• Infection with one strain does not confer immunity against other strains
• The epidemiology of HFMD-causing viruses is changing, with emerging strains becoming more prevalent
• A person can potentially contract HFMD multiple times throughout their lifetime, with each infection caused by a different enterovirus strain
• Prevention efforts are complicated by the diversity of causative agents and their evolution over time