Studies on Influenza Virus Transmission between Ferrets: the Public Health Risks Revisited

Fouchier, Ron A. M.

On the topic of intentional or accidental releases of viruses from laboratories involved in influenza virus transmission studies, it is important to note that during a decade of transmission studies on pandemic and epidemic strains derived from the 1918, 1957, 1968, and 2009 pandemics and on various wild-type and laboratoryadapted zoonotic viruses of subtypes H1, H2, H5, H7, and H9 (summarized in reference 16), no LAIs have been recorded. There have also been no recorded intentional or accidental releases during more than a century of research with human and animal influenza viruses, including highly pathogenic avian influenza viruses, even at times when biocontainment measures were largely nonexistent. Some have argued that the 1977 Russian influenza epidemic was the result of a laboratory accident (2) , but in 1977, influenza research was done under conditions of limited biocontainment, and attenuated and wild type strains were tested in humans. We do not know what happened in 1977, but we cannot conclude that the virus escaped a BSL3(Ï©) laboratory.