Page:Interim Staff Report on Investigation into Risky MPXV Experiment at the National Institute of Allergy and Infectious Diseases.pdf/15

 Republic of Congo for many decades. He’s found that clade 1 virus can kill a mouse at levels 1000 times lower than those needed with clade 2. To ﬁnd out why, Moss and his colleagues swapped dozens of clade 2 genes, one at a time, into clade 1 virus, hoping to see it become less deadly, but with no luck so far. Now, they are planning to try the opposite, endowing clade 2 virus with genes from its deadlier relative. [Bold added for emphasis].

As Members of the committee of jurisdiction responsible for the NIH and federal biomedical research, Republican Committee Leaders wrote to HHS to understand better the scope and potential risk of the proposed gene transfer experiment. As described above in the Science article, the experiment could result in a chimeric virus with the increased transmissibility of clade II viruses while retaining the high levels of lethality found in the clade I virus.

If the experiment transferred genes from clade IIb MPXV—which caused the 2022–2023 mpox epidemic—into clade I virus, the resulting chimeric virus could have a reproductive number (R0) of 1.10 to 2.40 coupled with a case fatality rate of 10 – 15 percent in the unvaccinated. The Science article did not specify which clade II virus the Moss team intended to use. However, the then ongoing 2022 – 2023 mpox outbreak would have given researchers an incentive to switch from studying clade IIa to clade IIb, both to assist in the response and for the chance to perform high-proﬁle research in what had historically been a low priority pathogen for research funding. Moreover, modifying ongoing research to study a pathogen causing an ongoing outbreak is a common practice and was done extensively in response to the emergence of SARS-CoV-2 and resulting COVID-19 pandemic.