Incidence rates using the MLE approach.

<p>The number of replications was 1000 for all the analyses and confidence limits (95% CL) were obtained by the percentile method. The inclusion window was chosen as follow. a) Period 1, 2 and 3: for times in the interval , for each age from 15 to 16, for each age from 17 to 22, for each age from 23 to 35, and for ages greater than 35. b) Period 4: for times in the interval , for each age from 15 to 16, for each age from 17 to 22, for each age from 23 to 35, and for ages greater than 35.