Of the viruses which continue to threaten human health, those classified at hazard group 4 represent the most difficult to work due to the requirement of high biological containment and the lack of approved therapies. As witnessed by the recent Ebola virus disease outbreak in West Africa, their propensity to cause widespread mortality and morbidity in human populations are apparent. This talk will cover intervention strategies that have been developed and tested by the PHE research group at Porton Down for two such viruses: Ebola virus and Crimean-Congo Haemorrhagic Fever virus.