Inactivation of SARS coronavirus by means of povidone-iodine, physical conditions and chemical reagents

Abstract

The efficacy of several povidone-iodine (PVP-I) products, a number of other chemical agents and various physical conditions were evaluated for their ability to inactivate the severe acute respiratory syndrome coronavirus (SARS-CoV). Treatment of SARS-CoV with PVP-I products for 2 min reduced the virus infectivity from 1.17 x 10(6) TCID(50)/ml to below the detectable level. The efficacy of 70% ethanol was equivalent to that of PVP-I products. Fixation of SARS-CoV-infected Vero E6 cells with a fixative including formalin, glutaraldehyde, methanol and acetone for 5 min or longer eliminated all infectivity. Heating the virus at 56 degrees C for 60 min or longer reduced the infectivity of the virus from 2.6 x 10(7) to undetectable levels. Irradiation with ultraviolet light at 134 microW/cm(2) for 15 min reduced the infectivity from 3.8 x 10(7) to 180 TCID(50)/ml; however, prolonged irradiation (60 min) failed to eliminate the remaining virus, leaving 18.8 TCID(50)/ml.

Fig. 1

Kinetics of SARS-CoV inactivation by heating. Aliquots of SARS-CoV were heated in a 56°C water bath for the indicated times. The heated virus aliquots were serially diluted and inoculated onto monolayers of Vero E6 cells grown in 96-well plates. After incubation for 48 h, the cytopathic effect in the cells was observed and the infectivity was determined by the TCID₅₀ method.

Fig. 2

Kinetics of SARS-CoV inactivation by UV irradiation. Aliquots of SARS-CoV were irradiated with UV light for the indicated times. The irradiated virus aliquots were serially diluted and inoculated onto monolayers of Vero E6 cells grown in 96-well plates. After incubation for 48 h, the cytopathic effect in the cells was observed and the infectivity was determined by the TCID₅₀ method.