A fomite is any nonliving object or surface that can carry and transfer infectious agents to a susceptible host through contact.
Transmission dynamics and survival factors
Fomite transmission occurs when microbes deposited on inanimate objects are transferred to individuals who touch those objects and subsequently touch their mucous membranes. Many pathogens, including viruses, bacteria and fungi, can persist on surfaces long enough to infect a new host. The ability of a microbe to survive outside its host depends on its intrinsic resilience and environmental conditions such as temperature, humidity and exposure to ultraviolet light. Nonporous surfaces like stainless steel and plastic often allow viruses such as influenza and coronaviruses to remain viable for hours to days, whereas porous materials may desiccate microbes more quickly. Hand hygiene and frequency of surface contact influence the probability of fomite-mediated transmission. Healthcare settings pose particular risks because contaminated equipment, gloves, bed rails and door handles can facilitate spread among patients and staff. Cleaning and disinfection reduce microbial loads and are essential components of infection control.
Examples and public health relevance
Common fomites include doorknobs, elevator buttons, utensils, toys, computer keyboards and mobile phones. Respiratory viruses such as respiratory syncytial virus, rhinoviruses and noroviruses readily contaminate shared surfaces, contributing to outbreaks in childcare centers and cruise ships. During the COVID-19 pandemic, studies showed that SARS-CoV-2 could persist on plastic and stainless steel for up to several days under laboratory conditions, underscoring the need for regular disinfection. Bacterial pathogens like Staphylococcus aureus, Clostridioides difficile and Escherichia coli can survive on hospital surfaces and medical devices, leading to nosocomial infections if hygiene protocols are inadequate. Fungal spores from dermatophytes may remain on combs or clothing and cause ringworm upon contact. Reducing fomite transmission requires proper cleaning, use of disinfectants effective against target organisms and promotion of hand hygiene to interrupt indirect contact chains.
Fomites remind us that infectious agents can be transmitted indirectly via objects we handle every day. Understanding how long pathogens persist on surfaces and implementing appropriate hygiene practices help reduce the risk of contact-mediated infections.
Related Terms: Transmission, Nosocomial infection, Disinfectant, Vector, Infection control