Vaccinia virus DIs: Classification recommendation of the ZKBS

Compared to its parent strain DIE, the vaccinia virus DIs is significantly attenuated by multiple passaging. Therefore, the DIs strain showed no pathogenicity in animal models in chickens, rabbits, mice, and guinea pigs, and only low pathogenicity in cynomolgus monkeys. The significantly reduced pathogenicity, particularly compared to the parent strain DIE and wild-type strains, has led the ZKBS to recommend classifying the DIs vaccinia virus in risk group 1 for genetic engineering work. We have provided a link to the ZKBS's detailed statement here. In addition to a detailed description of the genetic modification of the DIs strain compared to the parent strain, the statement also contains important information for further risk assessment for work with the DIs vaccinia virus. The viral functions responsible for attenuation are currently not fully understood. Therefore, when producing recombinant DIs by inserting nucleic acid fragments, it is necessary to examine the effect this has on pathogenicity. A similar problem exists with the production of recombinant vaccinia viruses of the MVA (Modified Vaccinia Virus Ankara) strain, on which the ZKBS has already issued a statement (statement of November 2018, Ref. No. 6790-10-74) . The risk assessment of recombinant DIs should therefore be carried out analogously to genetic engineering work with MVA, according to the aforementioned statement.