Inactivation of SARS-CoV-2 in Serum Using Physical Methods

Since 2019, many studies on coronavirus disease 2019, which has caused extensive damage as a pandemic, have been ongoing on a global scale. These include serological and biochemical studies using sera from patients and animal models. Testing with these sera must be performed after inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Heat treatment, UV irradiation, and/or gamma-ray irradiation have been used to inactivate viruses in the serum. Determining the inactivation conditions that ensure the inactivation of viruses and minimize the effect on test results after inactivation is important to ensure worker safety and the accuracy of test results. In this study, serum samples containing SARS-CoV-2 were subjected to heat, UV irradiation, and gamma irradiation to determine optimal inactivation conditions. The viral titers were below the detection limit after heating at 56°C for 1 h or 60°C for 15 min, UV-B irradiation with a transilluminator for 30 min, or gamma-ray irradiation with Co at 10 kGy. These results provide useful information for safe serological and biochemical experiments.