Long-term epidemiological patterns of pediatric infectious diseases in an urban district of Shanghai, 2015-2023

Understanding temporal and epidemiological patterns of pediatric infectious diseases is essential for developing targeted prevention strategies. This study investigated long-term incidence trends and epidemiological characteristics of notifiable infectious diseases among children in Xuhui District, Shanghai, from 2015 to 2023.

Surveillance data for children aged 0-17 years were obtained from the National Notifiable Disease Reporting System (NNDRS). Joinpoint regression was applied to identify temporal trends and significant inflection points. Age-specific distributions were analyzed and seasonal patterns were visualized using radar charts.

From 2015 to 2023, a total of 27,940 pediatric cases involving 23 notifiable infectious diseases were reported, corresponding to an average annual incidence of 2,421.68 per 100,000 children. Joinpoint regression identified a significant inflection point in 2021. Overall incidence declined during 2015-2021 (APC = -11.71%, 95% CI: -30.10 to -1.50, P = 0.029) and increased sharply thereafter (APC = 141.05%, 95% CI: 34.40-244.50, P < 0.001). When COVID-19 cases were excluded, no significant long-term trend was observed (APC = -4.2%, 95% CI: -23.60 -20.80, P = 0.71), indicating that the apparent post-2021 increase was driven primarily by COVID-19 notifications rather than a generalized resurgence of other pediatric infections. Disease-specific trajectories varied: influenza showed a pronounced post-pandemic surge, despite the absence of a significant long-term monotonic trend, whereas varicella, mumps, and scarlet fever continued to decline; in contrast, other infectious diarrhea showed a sustained upward trend (APC = 8.00%, 95% CI: 2.60-13.70, P = 0.003). Over time, the age distribution shifted toward school-aged children, with a significantly increasing proportion of cases occurring among those aged ≥4 years (χ ² _trend = 1475.594, P < 0.01).

Pediatric infectious disease epidemiology in Xuhui District underwent substantial changes across the pre-pandemic and post-pandemic periods. The sharp rise after 2021 was largely attributable to COVID-19, rather than a uniform rebound of all infectious diseases. Distinct temporal patterns across respiratory, enteric, and other infections underscore the importance of pathogen-specific transmission characteristics and age-related exposure in shaping long-term trends. These findings highlight the need for targeted, age-appropriate prevention strategies and sustained surveillance in the post-pandemic era.