Hand, Foot, and Mouth Disease (HFMD) is a common viral illness, most often affecting young children, that is primarily caused by enteroviruses such as Coxsackievirus A16 and Enterovirus 71. This highly contagious condition spreads easily, not only through direct person-to-person contact but also via contact with contaminated objects, known as fomites. Since the viruses can survive outside the body, understanding how long they remain viable on surfaces is important for controlling outbreaks.
The Virus’s Lifespan Outside the Body
The enteroviruses responsible for HFMD are non-enveloped, a structural feature that gives them robustness and allows them to persist in the environment longer than many other viruses. Studies suggest that these viruses can remain infectious on hard, inanimate objects for a range of time, from two days up to a week. The highest risk of transmission, however, is typically within the first 24 hours after a surface has been contaminated.
Several environmental factors strongly influence how long the virus remains viable on a surface. Temperature is a major factor, with cooler environments generally prolonging the survival time of the virus. Conversely, warmer temperatures tend to reduce the overall lifespan of the pathogen.
Humidity also plays a role in persistence. Moderate to high humidity can support the longevity of the virus by preventing the rapid drying out of the viral particles. Additionally, the initial concentration of the virus deposited on the surface, known as the viral load, directly impacts how long an infectious dose might remain.
High-Risk Surfaces and Materials
The material composition of a surface significantly affects the potential for the HFMD virus to persist. Non-porous materials, which do not absorb moisture, tend to support the virus’s survival for longer durations. These surfaces include hard plastics, metals like stainless steel, laminated countertops, and glazed tiles.
The virus is better retained on these smooth, non-porous surfaces because the viral particles and the moisture from bodily secretions do not dissipate quickly. High-risk items in a home or daycare setting include shared toys, plastic changing tables, doorknobs, light switches, and remote controls.
Conversely, porous surfaces, such as fabrics, carpet, and paper, generally allow the virus to dry out more rapidly, leading to a faster loss of infectivity. While the virus may not survive as long on these materials, they are still a potential source of contamination.
Essential Disinfection Protocols
Effectively inactivating the enteroviruses requires a two-step process: cleaning followed by disinfection with an appropriate agent. Surfaces must be cleaned first to remove organic matter. Organic material like dirt or bodily secretions can shield the virus, rendering disinfectants less effective. Therefore, a detergent and water cleaning step must precede the application of a disinfectant.
Since the viruses that cause HFMD are non-enveloped, they are resistant to many common disinfectants, including alcohol-based hand sanitizers and simple cleaning sprays. The most reliable and accessible agent for environmental disinfection is a freshly prepared solution of household chlorine bleach. A common and effective ratio for general disinfection of non-food contact surfaces is a solution of 8 teaspoons of household bleach mixed into one gallon of water.
Contact Time and Rinsing
For a disinfectant to work, it must remain on the surface for a specific period, known as the contact time. The surface must stay visibly wet with the bleach solution for at least five minutes to ensure the virus is fully inactivated.
After the required contact time, especially for surfaces that children might contact with their mouths, the area should be rinsed with clean water and allowed to air dry. When using commercially prepared, EPA-registered disinfectants, choose a product that lists effectiveness against non-enveloped viruses, such as poliovirus or norovirus, and strictly follow the manufacturer’s directions for dilution and contact time.