Using Routine Surveillance Data to Estimate the Epidemic Potential of Emerging Zoonoses: Application to the Emergence of US Swine Origin Influenza A H3N2v Virus

Cauchemez, Simon; Epperson, Scott; Biggerstaff, Matthew; Swerdlow, David; Finelli, Lyn; Ferguson, Neil M.

In many situations, both the case detection rate r and overdispersion parameter k are unknown. Interestingly, 12F always acts as a lower bound estimate of R. An upper bound for R can be obtained if it is possible to specify an upper bound r max for the case detection rate and a lower bound k min for the overdispersion parameter k (see Text S1). We specify k min~0 :16 that corresponds to the SARS scenario with superspreading events. Figure 5 shows how precision decreases as the upper bound r max increases. However, even in the scenario r max~1 0%, our approach can provide useful insights on transmissibility. For example, R is expected to be in intervals 0.20-0.25, 0.40-0.59, 0.50-0.87 for F = 80%, 60%, and 50%, respectively. For F#46%, we can only derive a lower bound on R. For example, if F = 20%, we find that R is $0.8.