It's only one claim in a large body of independent evidence pointing to bat coronavirus research at WIV being the source of the pandemic. Additionally, the collaboration between US-based coronavirus researchers and the Wuhan group dates back to 2013. The fact that the virus appeared pre-adapted to replicate rapidly in humans also is not aligned with previous zoonotic origins, where an adaptation process could be tracked over time as the genetic sequence evolved. Furthermore, the Ecohealth Alliance grant proposals to DARPA etc. for work to be done at WIV involved direct modification of the spike protein sequence, which in Sars-CoV2 has a codon usage pattern optimal for human cells. The question of whether WIV had the original bat coronavirus sequence that was modified into Sars-CoV2 is opaque due to WIV's deletion of their online database of sequences and further refusal to cooperate with investigations.
Overall, the most plausible scenario is that WIV researchers collected the original bat coronavirus sequence from cave(s) in southern China, then applied various research procedures such as serial passage through humanized mice lines and cell cultures, along with specific CRISPR-type modification of the spike protein, to generate a virus with optimal properties for replication in humans, which accidentally spread to human researchers and the people around them (including a superspreader event in the wet market). From there it spread globally by train and then airplane, causing millions of deaths and trillions in economic damage.
Why does it matter what the origin was? This kind of reckless and irresponsible research must be strictly curtailed to prevent it from happening again. There are dozens of mammalian viruses in nature that are harmless to people but which could be modified by these processes into novel pandemic threats to which human populations have little innate immunity.
Overall, the most plausible scenario is that WIV researchers collected the original bat coronavirus sequence from cave(s) in southern China, then applied various research procedures such as serial passage through humanized mice lines and cell cultures, along with specific CRISPR-type modification of the spike protein, to generate a virus with optimal properties for replication in humans, which accidentally spread to human researchers and the people around them (including a superspreader event in the wet market). From there it spread globally by train and then airplane, causing millions of deaths and trillions in economic damage.
Why does it matter what the origin was? This kind of reckless and irresponsible research must be strictly curtailed to prevent it from happening again. There are dozens of mammalian viruses in nature that are harmless to people but which could be modified by these processes into novel pandemic threats to which human populations have little innate immunity.