Evaluation of heating and chemical protocols for inactivating SARS-CoV-2

Abstract

Clinical samples collected in COVID-19 patients are commonly manipulated in BSL-2 laboratories for diagnostic purpose. We used the French norm NF-EN-14476+A2 derived from the European standard EN-14885. To avoid the risk of exposure of laboratory workers, we showed that Triton-X100 must be added to guanidinium thiocyanate-lysis buffers to obtain a 6-log reduction of infectious virus. Although heating protocol consisting of 92°C-15min was more effective rather than 56°C-30min and 60°C-60min to achieve 6-log reduction, it is not amenable for molecular detection on respiratory specimens because of important decrease of detectable RNA copies in the treated sample vs untreated sample. The 56°C-30min and 60°C-60min should be used for inactivation of serum / plasma samples for serology because of the 5log10 reduction of infectivity and low viral loads in blood specimens.