SARS-CoV-2 Survival on Surfaces and the Effect of UV-C Light

Abstract

The aim of this study was to establish the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on inanimate surfaces such as plastic, stainless steel, and glass during UV-C irradiation which is a physical means commonly utilized in sanitization procedures. The viral inactivation rate, virus half-life, and percentage of titer reduction after UV-C irradiation were assessed. Infectivity was maintained on plastic and glass until 120 h and on stainless steel until 72 h. The virus half-life was 5.3, 4.4, and 4.2 h on plastic, stainless steel, and glass, respectively. In all cases, titer decay was >99% after drop drying. UV-C irradiation efficiently reduced virus titer (99.99%), with doses ranging from 10.25 to 23.71 mJ/cm². Plastic and stainless steel needed higher doses to achieve target reduction. The total inactivation of SARS-CoV-2 on glass was obtained with the lower dose applied. SARS-CoV-2 survival can be long lasting on inanimate surfaces. It is worth recommending efficient disinfection protocols as a measure of prevention of viral spread. UV-C can provide rapid, efficient and sustainable sanitization procedures of different materials and surfaces. The dosages and mode of irradiation are important parameters to consider in their implementation as an important means to fight the SARS-CoV-2 pandemic.

Keywords: COVID-19; SARS-CoV-2; UV-C; glass; persistence; plastic; steel; surfaces.

Figure 1

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persistence on (A) plastic, (B) stainless steel and (C) glass. Ten microliters of SARS-CoV-2 viral stock were placed on different materials under controlled conditions (23–25°C and 40%–50% relative humidity). Infectious virus particles were carefully recovered at different time points (0 to 120 h) and processed for Median Tissue Culture Infectious Dose (TCID50) determination. SARS-CoV-2 infectivity kinetics (lines with filled dots) and linear regression analysis (red lines) are shown. Results are expressed as the mean ± standard deviation of 3 independent experiments (n = 3).

Figure 2

Effect of UV-C light (254 nm) on simulated fomites infection. Ten microliters of SARS-CoV-2 viral stock were placed on (A) plastic, (B) stainless steel and (C) glass, and recovered after 30 min (T₀) or exposed to different doses of UV-C (grey bars). After treatments, infectious virus particles were carefully recovered by washings and processed for TCID50 determination. A polystyrene plate covered by aluminum foil served as the control (white bar “shielded”). Results are expressed as the mean ± standard deviation of 3 independent experiments (n = 3).* p < 0.05, UV-C treated material vs. UV-C shielded.