Comments on Fouchier’s Calculation of Risk and Elapsed Time for Escape of a Laboratory-Acquired Infection from His Laboratory

Klotz, Lynn C.

To try to understand the meaning of Fouchier's simplistic equation y Ï­ 1/P 1 , I substitute into equation 1 the values calculated by Fouchier (P 1 Ï­ 1 Ï« 10 -6 , y Ï­ 1 Ï« 10 6 years, n Ï­ 1, for his single lab) to find E Ï­ 0.63. As I suspected, the value is high. While I do not know of anything significant that we might learn from this observation that Fouchier's calculation implicitly implies a high value for E, it at least answers the question put forth in the second paragraph of this letter about the meaning of his calculation of elapsed time to an escape. Recall that the highest value of the probability E is 1.0, which implies absolute certainty of an escape, which would take infinite elapsed time, y.