Which COVID studies pose a biohazard? Lack of clarity hampers research

When researchers at Boston University (BU) in Massachusetts inserted a gene from the Omicron variant of SARS-CoV-2 into a strain of the virus from the beginning of the pandemic, they were trying to understand why Omicron causes mild disease.

But the experiments, described in a 14 October preprint1, have ignited a red-hot controversy over what constitutes truly risky SARS-CoV-2 research — especially now that much of the world’s population has some immune protection from the virus and COVID-19 treatments are available.