Epidemiological characteristics and driving factors of co-circulation and co-detection of multiple respiratory pathogens: A multi-center surveillance study in China.

OBJECTIVES

Acute respiratory infections (ARIs) are driven by multiple co-circulating pathogens. We investigated pathogen co-detection patterns and interactions at multiple levels to identify factors shaping their dynamics.

STUDY

DESIGN

Population-based surveillance study.

METHODS

From November 2023 to December 2024, a multi-center surveillance of ARIs was conducted in 26 sentinel hospitals across Zhejiang Province, China. 14 respiratory pathogens were tested using PCR-based capillary electrophoresis. Population-level pathogen associations were assessed by Spearman's rank correlation and Granger causality tests. Pathogen interactions at the host level were analyzed using proportional distribution model and multivariable logistic regression.

RESULTS

Of 39,115 enrolled ARIs cases, 38,606 were tested for 14 respiratory pathogens. The overall pathogen positivity was 54.84% (21,173/38,606), with co-detections observed in 12.47% (4815/38,606) of ARIs cases. Streptococcus pneumoniae was the most prevalent pathogen and the primary driver of co-detections. A directed predictive network was identified, with RSV, HRV, and HPIV as key hubs. Viral-bacterial synergy was common in children, while adults and the elderly showed significant viral interference, most notably between IFV-A and IFV-B (OR = 0.06). Strong influenza interference was observed in the cold season (IFV-A-IFV-B, OR = 0.10), whereas the warm season was dominated by broader pathogen synergy, alongside notable negative associations such as IFV-A-SARS-CoV-2 (OR = 0.17).

CONCLUSIONS

This study reveals that age- and season-dependent pathogen interactions may shape the dynamic patterns of multiple respiratory pathogens, thereby highlighting the importance of considering such interactions in public health strategies.