Effect of Inactivation Methods on SARS-CoV-2 Virion Protein and Structure

The risk posed by Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) dictates that live-virus research is conducted in a biosafety level 3 (BSL3) facility. Working with SARS-CoV-2 at lower biosafety levels can expedite research yet requires the virus to be fully inactivated. In this study, we validated and compared two protocols for inactivating SARS-CoV-2: heat treatment and ultraviolet irradiation. The two methods were optimized to render the virus completely incapable of infection while limiting the destructive effects of inactivation. We observed that 15 min of incubation at 65 degrees C completely inactivates high titer viral stocks. Complete inactivation was also achieved with minimal amounts of UV power (70,000 mu J/cm(2)), which is 100-fold less power than comparable studies. Once validated, the two methods were then compared for viral RNA quantification, virion purification, and antibody detection assays. We observed that UV irradiation resulted in a 2-log reduction of detectable genomes compared to heat inactivation. Protein yield following virion enrichment was equivalent for all inactivation conditions, but the quality of resulting viral proteins and virions were differentially impacted depending on inactivation method and time. Here, we outline the strengths and weaknesses of each method so that investigators might choose the one which best meets their research goals.

Automated summary

Research has shown that heat treatment for 15 minutes at 65 degrees Celsius or UV irradiation at 70,000 mu J/cm(2) can completely inactivate SARS-CoV-2, offering efficient options for research purposes. It has also been observed that UV irradiation results in a 2-log reduction of detectable viral genomes compared to heat inactivation, indicating differences in effectiveness between the two methods.