UV-C irradiation-based inactivation of SARS-CoV-2 in contaminated porous and non-porous surfaces
Ana Luísa Tomás, Anna Reichel, Patrícia M. Silva, Pedro G. Silva, João L. Pinto, Inês Calado, Joana Campos, Ilídio Silva, Vasco Machado, Roberto Laranjeira, Paulo Abreu, P. M. Mendes, N. Ben Sédrine, Nuno C. Santos
Abstract
The SARS-CoV-2 pandemic emphasized effective cleaning and disinfection of common spaces as an essential tool to mitigate viral transmission. To address this problem, decontamination technologies based on UV-C light are being used. Our aim was to generate coherent and translational datasets of effective UV-C-based SARS-CoV-2 inactivation protocols for the application on surfaces with different compositions. Virus infectivity after UV-C exposure of several porous (bed linen, various types of upholstery, synthetic leather, clothing) and non-porous (types of plastic, stainless steel, glass, ceramics, wood, vinyl) materials was assessed through plaque assay using a SARS-CoV-2 clinical isolate. Studies were conducted under controlled environmental conditions with a 254-nm UV-C lamp and irradiance values quantified using a 254 nm-calibrated sensor. From each material type (porous/non-porous), a product was selected as a reference to assess the decrease of infectious virus particles as a function of UV-C dose, before testing the remaining surfaces with selected critical doses. Our data show that UV-C irradiation is effectively inactivating SARS-CoV-2 on both material types. However, an efficient reduction in the number of infectious viral particles was achieved much faster and at lower doses on non-porous surfaces. The treatment effectiveness on porous surfaces was demonstrated to be highly variable and composition-dependent. Our findings will support the optimization of UV-C-based technologies, enabling the adoption of effective customizable protocols that will help to ensure higher antiviral efficiencies.