Ignacio González Bravo
Research director at the Laboratory of Infectious Diseases and Vectors: Ecology, Genetics, Evolution and Control (MIVEGEC) of the French National Center for Scientific Research (CNRS).
It is not new for the FBI to defend the laboratory origin hypothesis for SARS-CoV-2. It is new for DOE to do so. As a scientist, I believe that this communication is fundamentally unscientific, in that it contains neither new data nor new information to support the new interpretation. It is more parsimonious to interpret it as part of a communication war strategy between the US and China, rather than as part of an effort to understand the origin of the virus.
Both alternatives are possible: i) natural origin and jumping species(es), and ii) targeted modification in a laboratory and loss of containment. The question is to elucidate how likely each is.
With respect to the first, viral diversity in nature and epidemiological patterns at the onset of the epidemic suggest natural origin. As a criticism of this interpretation, these closely related viruses have not been detected near Wuhan, but in Laos, and the occurrence of cases in the Wuhan market does not necessarily exclude a possible escape from the laboratory.
Regarding the second interpretation, certain functionalities in SARS-CoV-2, which differentiate it from other viruses very similar to it, suggest a discontinuity in its evolutionary history. Criticising this interpretation, the origin of the omicron lineage implies the accumulation of more than twenty mutations with respect to its ancestor, over a long period of time during which variants of this lineage were never detected, and there was no need to invoke directed evolution in the laboratory to justify its emergence. The explanation offered is the circulation of viruses of this lineage among immunosuppressed populations, which allowed the accumulation of intermediate mutants that would not have thrived in other human populations.