Epidemiology and burden of respiratory virus-associated acute respiratory infections: a multi-source integrated population-based surveillance study in Chongqing

Abstract Background Acute respiratory infections (ARIs), particularly severe acute respiratory infections (SARIs), impose a huge disease burden globally. Respiratory viruses are key etiological agents of ARIs. Population-based data on respiratory virus disease burden in China are limited, with most studies focusing on single pathogens and lacking population-level incidence and hospitalization estimates. Methods We integrated data from national hospital-based surveillance, local health system electronic medical records (EMRs), and census records in Chongqing from October 2023 to April 2025. We also conducted a community-based healthcare utilization survey and a pilot survey. We analyzed the seasonality of six respiratory viruses and used Joinpoint software to characterize age-specific epidemiological trends. Furthermore, we identified risk factors for severe acute respiratory infection (SARI). A modified multiplier model was employed to estimate population-based incidence and hospitalization rates of ARI associated with these viruses. Results We included 16,363 respiratory infection patients (12,669 outpatients, 3,694 inpatients). Most viruses resumed pre-COVID-19 seasonal patterns. The detection rate of influenza virus (IFV) peaked in adolescents and adults; respiratory syncytial virus (RSV) and human parainfluenza virus (HPIV) mainly affected infants and the elderly; human adenovirus (HAdv), human rhinovirus (HRV), and human metapneumovirus (HMPV) were most prevalent in preschoolers. RSV infection was significantly associated with a higher risk of SARI compared with other respiratory viruses (RSV vs. IFV: adjusted odds ratio [aOR], 95% confidence interval [CI]: 7.88, 5.4–11.51; RSV vs. HRV: 1.52, 1.13–2.04; RSV vs. HAdv: 3.21, 2.14–4.81; RSV vs. HMPV: 1.76, 1.24–2.50; RSV vs. HPIV: 1.63, 1.14–2.33). Incidence and hospitalization rates (per 100,000 person-years) of HRV (30,183; 2,153), HMPV (22,774; 514), RSV (22,181; 2,065), IFV (13,086; 807), HPIV (7,824; 556), and HAdv (6,991; 1,487) were highest in children under 5 years of age. Hospitalization rates rose again in those aged ≥ 60 years: HRV (170), RSV (80), IFV (70), HMPV (54), HAdv (27), HPIV (23). Conclusions Distinct age distributions and the high SARI risk of specific viruses such as RSV support targeted prevention. Integrating multi-source surveillance with sentinel surveys and standardizing the ARI case definition can yield population-level, real-world estimates of incidence and hospitalization rates for these viruses.