Figure 2

Epidemic curve and sequential Bayesian estimation of the distribution of R for the A/H7N9 influenza outbreak in Shanghai, China. A) Daily number of laboratory-confirmed A/H7N9 influenza cases by date of symptoms onset. Vertical dashed lines indicate the timing of the preemptive live bird market closures in Shanghai (6 April). B) Evolution of R estimates as data accumulate over time, assuming a prolonged serial interval of six days (latent period, k^-1 = 3 days and infectious period, γ-¹ = 3 days). Median R (solid red line) and 95% credible intervals (dashed red lines) are shown. The horizontal dotted line indicates the threshold at R = 1, above which large epidemics are expected to occur. R, reproduction number.