Danger of Potential-Pandemic-Pathogen Research Enterprises

Klotz, Lynn C.

Furthermore, there is a rather arcane subject in probability, branching theory, which allows prediction of the likelihood of uncontrolled spread of any pathogen based on its observed reproductive number (R o ) value and the variance to mean of the R o . A large variance to mean could occur due to superspreaders, for instance, some people infected with SARS virus. For a wide range of R o values, Lipsitch and coworkers have calculated the probability of uncontrolled spread (see Fig. 4a in their study [9] ). For a single infected individual with an R o of 2, the probability of an uncontrolled outbreak ranges from 10% (spread of R o s) to 80% (uniform R o ). Thus, the pandemic likelihood from a single infected individual is potentially large. I suspect that future risk assessments will confirm that once a highly contagious potentially pandemic pathogen escapes, the probability of an uncontrolled outbreak is significant, leading again to a focus on the probability of a laboratory escape as the important factor.