Comment by David Bloom

Many questions about the origins of SARS-CoV-2 remain unanswered and may never be fully resolved. We cannot currently disprove the lab leak hypothesis. Nevertheless, the lines of evidence needed to validate one hypothesis over another are not epistemically comparable. Validating the zoonotic origin is a scientific question that relies on history, epidemiology, and genomic analysis, that when taken together, support a natural spillover as the probable origin. Validating the lab leak hypothesis requires intelligence evidence that the WIV possessed or carried out work on a SARS-CoV-2 precursor virus prior to the pandemic. Neither the scientific community nor multiple western intelligence agencies have found such evidence.