Fig. 2

The patterns of ODI-related COVID-19 disease severe rate and case fatality rate examined by Join-Point regression models. A‒D indicate the overall severe rate and that stratified by sex, age and regions, respectively. E–H indicate the overall case fatality rate and that stratified by sex, age and regions, respectively. For each panel, red and blue points indicate severe rates and case fatality rates at each day of ODI, which were fitted by the red or blue curve. The arrows indicate the turning points of fitted curves. The Annual Percent Change (APC) value of each fitted curve was provided for each panel. *APC is significantly from zero at alpha = 0.05 level