Figure 3

Epidemic dynamics of influenza A (H1N1-2009) in a primary school, Madagascar. A. A comparison of the observed daily incidence (dots) against conditional expected values with and without accounting for the depletion of susceptible individuals (solid and dashed lines, respectively). Day 0 represents 6 October 2009 onwards. B. Maximum likelihood estimate (solid line) and the 95% confidence intervals (dotted lines) of the effective reproduction number without accounting for interventions. We assumed that the number of cases on each day was sufficiently characterized by Poisson distribution. The estimates of the effective reproduction number reflect the time-dependent reduction in the transmissibility due to depletion of susceptible individuals only. Horizontal dashed line represents the threshold level of R = 1 above which it implies that the epidemic can continue without public health interventions.