Figure 1: The scatter plot and the fitted regression models of the monthly number of HEV cases and GBS cases (with +1 month lag) in Hong Kong from 2004 to 2018. The triangular dots represent the observed data, and the curves are the fitted regression models, where shading areas represent 95% confidence interval (CI). Downward triangles (blue) are the number of cases reported between 2004 and 2009, and upward triangles (red) are the number of cases reported between 2010 and 2018. The blue/red curve is the fitted regression model using data before/after 2010. The dark green curve is the fitted regression model using data from 2004 to 2018. The dashed curve (blue) indicates that the regression coefficient is not statistically significant.