an increasing trendp = 0.013
We identified seasonal joinpoint trends in Shigella outbreak frequency, revealing an increasing trend until October, with an APC of 3.03% (95% CI: 0.76 to 7.60, p = 0.013), and a decreasing trend thereafter, with an APC of −25.79% (95% CI: −37.31 to −9.21, p < 0.05) ( Supplementary Figure S4 ).