Model Estimates of Sensitivity for Influenza A Testing as Reported to the RVDSS, by Influenza Season.

Note: Estimates of sensitivity by influenza season were obtained by estimating separate β5,y parameters, one for each season. Noting that the null value for sensitivity is 100%, as 100% sensitivity implies that there should no association between the number of influenza negative and influenza positive tests, the season specific estimates appear to be reasonably consistent. Season specific differences in the estimated sensitivity may be due to irregular reporting and the tendency of data irregularities to bias the model parameters β5,y towards the null, or sensitivity towards 1. A value of 100% for sensitivity implies that there is no association between the number of influenza negative and influenza positive tests. The 2000/01 and 2002/03 season estimates (both H1N1/B seasons) were uninformative. This lack of statistical significance and wide confidence intervals were attributed to the relatively small number of influenza A positive specimens in these two H1N1 seasons. A shift in influenza A confirmations towards younger ages was noted during the H1N1 seasons. Testing a larger proportion of children may result in an improvement in the overall test sensitivity.ns: Not statistically significant. The null value for sensitivity is 100%. With 100% sensitivity no association between the number of influenza negative and influenza positive tests would be expected.n/a: Not available. Estimate was out of range and not statistically significant.