Who touched that? Interconnection of high-touch surfaces drives pathogen spread in public spaces

BACKGROUND: Surface contamination via hands plays an important role in pathogen spread in public spaces. This study aimed to identify frequently touched surfaces and evaluate the spread of a surrogate virus in a hotel lobby. METHODS: In a working hotel lobby, observation was performed (30 hours) to identify the surfaces and objects touched. An entry doorknob and first floor elevator button were seeded with a bacteriophage (Phi-X174) tracer; 4 hours later 25 surfaces were swabbed to determine tracer distribution and contamination levels. RESULTS: A total of 324 individuals performed 627 touches over 13 different fomites in the hotel lobby. The elevator button and front desk counter were the most frequently touched (32 and 22% of all touches respectively), with 55% of individuals touching the elevator button and 79% touching either the elevator button, the front desk counter, or both. More than half (56%) touched 2 or more surfaces; there were 314 interactions between surfaces. Touches from the elevator button to other surfaces (92 interactions) and from other surfaces to the elevator button (41) made up 42% of all interactions and connected the elevator button to 9 other fomites including doors, countertops, seating, a credit card reader and a hand sanitizer pump. From two seeded sites, the tracer spread to 13 surfaces over 4 hours. The most contaminated surfaces were tables, counter tops and door handles. Other contaminated objects were the luggage cart handle, sanitizer pump, and computer equipment. CONCLUSIONS: Surfaces in the hotel lobby were frequently touched and highly interconnected, resulting in extensive spread of surface contamination in as little as 4 hours. This study demonstrates the importance of hands in distributing contamination between shared surfaces and highlights the need for hand and surface hygiene interventions to disrupt the journey of the germ in public settings. KEY MESSAGES: • Frequently touched surfaces in public spaces are interconnected. • Interconnection of people via touched surfaces drives the spread of pathogens in a public setting.