LETTER
In a Letter to the Editor of mBio, Professor Ron Fouchier published a calculation (1) in which he finds a very low probability, P1, for a laboratory-acquired infection (LAI) for a single lab for a single year. Claiming numerous safety precautions in his biosafety level 3 (BSL3+) laboratory, Fouchier calculates P1 = 1 × 10–7 per person per year, and since there are 10 workers with access to his laboratory, P1 = 1 × 10–6 per lab per year. Compare this to P1 = 2 × 10–3 per lab per year for BSL3 laboratories calculated from CDC statistics for undetected or unreported LAIs (2, 3), here called “community LAIs,” as it is assumed that an undetected or unreported LAI represents an infection that has traveled outside the lab and into the community.
Recently reported escapes of LAIs from high-level biocontainment at CDC laboratories (4) and the long history of LAIs and other escapes from laboratories (5) also argue that Fouchier's value for P1 is too low. Lipsitch and Inglesby (6) have supplied additional arguments as to why the Fouchier value for P1 is likely much too low.
Fouchier uses a simplistic formula, y = 1/P1, to calculate the elapsed time in years for an LAI to escape from his laboratory, y = 1/(1 × 10 …
