Model term Beta coefficient    (95% CI) Incidence rate ratio (95% CI) sin(time * 2 * π) 0.74 (0.41 to 1.10) - cos(time * 2 * π) -0.22 (-0.48 to 0.17) - Time (years) 0.34 (0.16 to 0.52) 1.40 (1.17 to 1.68) Intervention† -0.69 (-1.35 to 0.12) 0.54 (0.26 to 1.13) †From May 2012 exposed, otherwise unexposed. CI: confidence interval

Table 1: Incidence rate ratios derived from a Poisson regression model of monthly counts of L. pneumophila cases reported from the Auckland Region.