Scientists say coronavirus can stay alive for long period under high heat, posing threat to lab workers

Based on an experiment conducted by a team of French scientist, it was found that the novel coronavirus can survive long exposure to immense temperature. Professor Remi Charrel, along with his colleagues at the Aix-Marseille University located in southern France, discovered that some strains of the virus that causes COVID-19 were still alive to be able to replicate after being placed under the temperature of 60 degrees Celsius for an hour. In order to completely kill the virus, the group of scientists had to bring the temperature to almost 100 degree Celsius. Due to this, it now shows that the safety of lab staff working with the virus can be compromised. To carry out the experiment, the scientists infected an African green monkey kidney cells, which is the usual host material used for viral activity tests, with a strain taken from a positive patient in Berlin, Germany. The cells were stored into tubes under two different contrasting environments, one “clean” and the other “dirty” with animal protein in order to encourage biological contamination in real-life samples. Upon heating up, the viral strains in the clean environment were killed, however, some strains in the dirty environment survived. Although the heating process managed to remove all infectivity but there were still enough living strains that could start another round of infections. This was written in the scientists’ non-peer-reviewed paper released on bioRxic.org on Saturday (11 April).

Lab workers at risk

Globally, there have been demand for tests to be done on the new coronavirus. However, some of the tests have to be carried out in less protected laboratories, exposing the lab technicians directly to the samples. The method of heating up the virus under 60 degree Celsius for an hour is a protocol that has been followed by many testing labs around the world to kill a wide range of deadly viruses, including Ebola. However, for the novel coronavirus, this temperature may be sufficient for samples with low viral loads as it could kill the majority of the strains. But, the researchers noted that it might be dangerous for samples with extremely high amounts of the virus. To curb this, the French scientists discovered that a higher heat can curb the problem. For example, if the samples are heat to 92 degree Celsius for just 15 minutes, it could result to the complete inactivity of the virus. Unfortunately, such high temperature could also badly fragment the virus’ RNA and decrease the sensitivity of the test. As such, the team proposed to use chemicals instead of heat to kill the virus, and strike a balance between the safety of lab staff and detection efficiency. “The results presented in this study should help to choose the best suited protocol for inactivation in order to prevent exposure of laboratory personnel in charge of direct and indirect detection of Sars-CoV-2 for diagnostic purpose,” wrote the authors. Separately, a microbiologist at the Chinese Academy of Sciences in Beijing revealed that Chinese test labs knew about the risk that lab workers face and have taken extra precautions. Some of the measures implemented include making it compulsory for all lab staff to dress in a full hazmat suit when dealing with the virus sample, even after deactivation. Although the French experiment provided good information regarding the virus, but the scientist noted that real life situation could be more complicated than the lab stimulations. “The virus behaves quite differently with a change in environment. Many research projects are still under way to solve these puzzles,” he said. This latest experiment discredits the earlier theory that warm weather could help to kill the novel coronavirus, and that the cases will be reduced when summer approaches.