While biosafety at the CSIRO laboratory in Australia is reported to be sufficient to preclude accidental release of infected test animals, concern exists that genetically modified pathogens could be accidentally released. Without available countermeasures, such a release could pose a threat to endemic species and possibly to humans. This concern is likely to grow as biodefense research expands and evolves globally.

Jackson and Ramshaw drew widespread criticism from both the media and the scientific community for their research, however, work on how viruses expressing IL-4 can shut down the immune response continues. In 2003 another media frenzy started when Dr. Mark Buller and colleagues at St. Louis University announced that they had expanded on the original mousepox work by creating a mousepox virus that expresses IL-4 at even higher levels than the Jackson transgenic virus. By inserting the gene that encodes IL-4 in a different part of the genome and using a strong promoter, Buller was able to express enough IL-4 to shut down the immune response and kill 100% of immunized mice even when they were being treated with the antiviral drug cidofovir. In addition, Buller announced that he had made similar modifications to a cowpox virus and plans to test it on animals at the US Army Medical Research Institute of Infectious Disease facility in Fort Detrick were already underway. Ian Ramshaw has also continued to work on manipulating host immune response with mousepox and rabbitpox viruses.