Synthetic horsepox immunization shows promise in tests to counter smallpox

Mice immunized by a synthetic horsepox virus show promise in the development of an alternative smallpox vaccine, outside the boundaries of existing–often troublesome–vaccinia virus use.

In a study published in the Open Access journal PLOS ONE, researchers from the University of Alberta, Canada, synthesized horsepox virus from DNA fragments and tested HPXV on live mice. Given that HPXV is believed to have been eradicated, the researchers generated their own through chemically-synthesized DNA fragments based on its published genome. Cell culture allowed them to consequently activate the virus.

The results were a lab creation that was at once less virulent than modern vaccinia but also comes with its own risks of misuse. While it does not cause an immediate biosafety or biosecurity risk, researchers paired their worries in that regard with the good news this effort represents: engineered viruses could potentially improve vaccines.

In the case of the vaccinia virus, the problem is that, while it protects against smallpox, it often comes with serious side effects in bearers. HPXV induced less severe reactions than vaccinia in mice, despite producing similar levels of protective antibodies.

Researchers not only published their findings in PLOS, they also submitted them to the World Health Organization Advisory Committee of Variola Virus Research. All efforts therein were conducted with the assistance of the University of Alberta’s biosafety program.