# The value of primary care networks for molecular surveillance of paediatric respiratory infections

## TL;DR

This study shows how primary care centers in Catalonia effectively track respiratory viruses in children, revealing patterns and co-infections similar to broader community data.

## Contribution

The study demonstrates the value of primary care networks for molecular surveillance of pediatric respiratory infections in a real-world setting.

## Key findings

- Primary care centers showed viral prevalence patterns similar to hospital and community data, including rhinovirus and adenovirus year-round.
- Co-infections were common, with bocavirus showing the highest rate, while influenza and SARS-CoV-2 had lower co-infection rates.
- Genomic analysis identified multiple virus types and variants, including EV-D68, CV-A6, and SARS-CoV-2 variants matching national trends.

## Abstract

This study aimed to provide a comprehensive overview of SARS-CoV-2 and other respiratory viruses co-infections and analyse the value of Primary Care Centres (PCCs) as a sentinel network for molecular surveillance of paediatric respiratory viral infections in Catalonia (Spain).

Between October 2021 and April 2024, upper respiratory tract samples were collected from children under 15 years of age presenting with acute respiratory symptoms at different PCCs across Catalonia. The detection of respiratory viruses was performed using commercial multiplex RT-PCR and transcription-mediated amplification-based assays. The genetic characterisation of select viruses (adenoviruses (AdV), enteroviruses (EV), influenza viruses, SARS-CoV-2) was performed via partial or whole genome sequencing. The results were then compared with hospital-based data and the regional surveillance system (SIVIC).

Among 1,401 positive samples from 1,329 cases, the most prevalent viruses were rhinovirus (RV) (22.77%), SARS-CoV-2 (12.35%), influenza A(H3) viruses (11.06%) and AdV (9.21%). Viral circulation followed typical seasonal patterns, with RV and AdV detected year-round, and influenza and respiratory syncytial virus peaking in winter, showing prevalences similar to those observed in hospital settings and broader community settings. Co-infections were frequent (up to 53.3% for bocavirus), while influenza and SARS-CoV-2 showed the lowest co-infection rates, suggesting possible viral interference. Genomic analysis revealed circulation of different EV (e.g., EV-D68, CV-A6, E-11, etc.) and AdV (B3, C2) types, multiple FLUAV and FLUBV genetic clades and SARS-CoV-2 variants consistent with national waves.

This study highlights the complexity of respiratory virus circulation and co-infections dynamics in paediatric primary care patients. A notable observation was the generally similar viral distribution between PCCs and the community, reinforcing the value of studying this population. The findings also underscore the importance of continued molecular surveillance to inform public health strategies and clinical management of respiratory infections in children.

The online version contains supplementary material available at 10.1007/s10096-025-05353-9.