Reply to “Studies on Influenza Virus Transmission between Ferrets: the Public Health Risks Revisited”

Lipsitch, Marc; Inglesby, Thomas V.

Any risk assessment, however, must explicitly account for the possibility of human error or malicious removal of the agents from the source lab, circumventing these enhanced safeguards (10) . As observed by Kimman et al., "in the majority of cases of LAIs a direct cause could not be assigned. . ., suggesting that a failure was not noticed in many cases or that containment may have been insufficient" (9) . In relation to the gain-of-function risk assessment, Gavin Huntley-Fenner, a speaker at the National Academy of Sciences Symposium on Gain-of-Function, wrote "we need to plan as though human error is inevitable. Research suggests that even the most experienced and knowledgeable workers sometimes cut corners and that everyone is susceptible to distraction, fatigue and faulty reasoning" (10) . In this regard, it is notable that all three recently publicized CDC laboratory incidents (11, 12) involved removal of infectious material from the BSL3 containment facilities in which they were handled, in the false belief that the material was not infectious (the anthrax agent and Ebola virus) or in the false belief that the material did not contain a highly pathogenic avian influenza (HPAI) contaminant (influenza virus). Under such circumstances, even the highestfunctioning mechanical systems and best-trained personnel in the source lab cannot prevent accidents in the destination lab.