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. 2020 Sep 29;58(10):886–891. doi: 10.1007/s12275-020-0335-6

Development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) thermal inactivation method with preservation of diagnostic sensitivity

Young-Il Kim 1,2,#, Mark Anthony B Casel 1,2,#, Se-Mi Kim 1, Seong-Gyu Kim 1, Su-Jin Park 1,2, Eun-Ha Kim 1,2, Hye Won Jeong 1, Haryoung Poo 3, Young Ki Choi 1,2,✉
PMCID: PMC7522010  PMID: 32989642

Abstract

Various treatments and agents had been reported to inactivate RNA viruses. Of these, thermal inactivation is generally considered an effective and cheap method of sample preparation for downstream assays. The purpose of this study is to establish a safe inactivation method for SARS-CoV-2 without compromising the amount of amplifiable viral genome necessary for clinical diagnoses. In this study, we demonstrate the infectivity and genomic stability of SARSCoV- 2 by thermal inactivation at both 56°C and 65°C. The results substantiate that viable SARS-CoV-2 is readily inactivated when incubated at 56°C for 30 min or at 65°C for 10 min. qRT-PCR of specimens heat-inactivated at 56°C for 30 min or 65°C for 15 min revealed similar genomic RNA stability compared with non-heat inactivated specimens. Further, we demonstrate that 30 min of thermal inactivation at 56°C could inactivate viable viruses from clinical COVID-19 specimens without attenuating the qRT-PCR diagnostic sensitivity. Heat treatment of clinical specimens from COVID-19 patients at 56°C for 30 min or 65°C for 15 min could be a useful method for the inactivation of a highly contagious agent, SARS-CoV-2. Use of this method would reduce the potential for secondary infections in BSL2 conditions during diagnostic procedures. Importantly, infectious virus can be inactivated in clinical specimens without compromising the sensitivity of the diagnostic RT-PCR assay.

Keywords: SARS-CoV-2, heat inactivation, COVID-19, genomic stability, RT-PCR

Acknowledgments

This work was supported by the Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program (KGM9942011) and conducted during the research year of Chungbuk National University in 2018 for Young Ki Choi.

Footnotes

Conflict of Interest

The authors have declared that no conflict of interest exists.

These authors contributed equally to this work.

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