Tonix announced the new synthetic vaccinia virus quietly, burying the news in a press release for a poster that the firm presented at the American Society for Microbiology’s annual biodefense science and policy conference. The poster focused on the progress the company was making in testing Evans’s synthetic horsepox virus for use as a vaccine against smallpox, which Tonix calls TNX-801. Current smallpox vaccines are based on live vaccinia virus that is grown using cell culture technology. Tonix’s poster also references another smallpox vaccine candidate the company is testing, one based on a synthetic version of the vaccinia virus that Tonix is calling TNX-1200. While the vaccinia and horsepox viruses are not themselves serious threats to human health, there are several reasons why this new development in synthetic biology is problematic.
Tonix has apparently ignored the concerns that many biosecurity experts, including myself, have raised. Given the close genetic similarity among orthopoxviruses like the horsepox, variola, and vaccinia viruses, the laboratory techniques that can be used to create one can also be used to produce others–most worryingly, the smallpox-causing variola virus. Indeed, Evans has said as much himself, once pointing out that his research “was a stark demonstration that this could also be done with variola virus.” Evans’s lab used the same technique to produce the synthetic vaccinia virus for Tonix as it did to synthesize the horsepox virus.
Unlike in other cases of controversial dual-use research, the risks posed by the synthesis of orthopoxviruses are not offset by any significant benefits. In 2018, I wrote that the benefits of using Evans and Tonix’s horsepox virus as a smallpox vaccine rested on a weak scientific foundation, and an even weaker business case. The case for synthesizing vaccinia is more dubious.