Incidence and trends for notifiable infectious diseases in Shenyang, China, 2005-2024

Background Infectious diseases remain a major global public health challenge. Evolving epidemiological patterns and considerable regional variation underscore the need for localized, real-time surveillance and assessment. This study examines the incidence and trends of notifiable infectious diseases (NIDs) in Shenyang from 2005 to 2024 to generate an evidence base for regional and national public health strategy formulation. Methods The data of NIDs in Shenyang from January 1, 2005 to December 31, 2024 were obtained from the National Notifiable Diseases Reporting System (NNDRS). Joinpoint regression analysis was used to determine the changing trend of annual incidence. Results Between 2005 and 2024, Shenyang reported 668,476 cases of 33 notifiable infectious diseases, all classified as Class B (58.8%) or C (41.2%). Respiratory infections were the most common (47.4%), followed by fecal-oral (29.8%) and blood-borne/sexual transmission (21.7%). The overall annual age-standardized incidence rate (ASIR) averaged 481.49 per 100,000 population, increasing significantly from 360.72 to 880.18 per 100,000 over the 20-year period (AAPC: 6.20%; 95%CI: 2.11%,10.04%), representing a 144% overall rise. Males exhibited a higher average annual ASIR (565.30 per 100,000) compared to females (393.35 per 100,000). A pronounced upward trend was observed in Class C diseases (AAPC: 12.75%; 95%CI: 7.47%,18.19%), whereas Class B diseases remained stable. Respiratory-transmitted diseases showed the strongest growth (AAPC: 12.75%; 95%CI: 7.47%,18.19%), followed by those transmitted via the fecal-oral route (AAPC: 4.79%; 95%CI: 0.42%,9.65%), while blood-borne/sexually transmitted diseases declined slightly (AAPC: -2.52%; 95%CI: -4.11%,-0.30%). Vaccine-preventable diseases (VPDs) declined markedly (AAPC: -6.98%; 95%CI: -8.62%,-5.30%), in contrast to a substantial increase in non-VPDs (AAPC: 13.66%; 95%CI: 10.04%,17.68%). Conclusions The overall incidence of NIDs in Shenyang was lower than the national average, however, the respiratory infections pose a relatively high disease burden and warrant focused control. It is noteworthy that the incidence of VPDs has declined significantly over the past two decades, demonstrating the marked success of immunization strategies.