Impact of immune status on respiratory virus prevalence and co-detection patterns: a retrospective analysis (2019–2024)

This study aimed to describe yearly laboratory-based detection patterns of respiratory viruses, excluding SARS-CoV-2, among PCR-confirmed positive cases identified through multiplex respiratory polymerase chain reaction (PCR) testing over a six-year period.It focused on the distribution of viruses across different age groups and also differences between immunocompromised and immunocompetent patients. This retrospective study included 5,282 PCR-confirmed positive patients identified through respiratory multiplex PCR testing between January 2019 and December 2024. Patient ages ranged from pediatric to adult, with a mean age of 29.4 years; 46.1% were female and 53.9% were male. Nasopharyngeal swab samples were analyzed using real-time multiplex PCR targeting multiple respiratory viruses, including Influenza A/B, human adenovirus, human bocavirus, seasonal coronaviruses, enterovirus, human parechovirus, human rhinovirus, RSV, and human parainfluenza virus types 1–4. Single and multiple viral pathogens were identified within PCR-positive samples. Among PCR-confirmed positive patients, 74.6% were immunocompetent whereas 25.4% were immunocompromised. Notably, immunocompromised individuals were significantly older with a higher proportion of males (p < 0.05). A total of 6136 respiratory pathogens were detected. Co-detections occurred in 13.0% of the samples. Human rhinovirus was the most frequently identified pathogen (32.5%), followed by influenza A (13.6%) and RSV (12.5%). Over the study period, variations in laboratory detection numbers were observed. Co-detections were most commonly seen with human rhinovirus, RSV, and human adenovirus. While human rhinovirus and RSV were frequently detected across all age groups, influenza A was more common in adults, whereas human adenovirus and human bocavirus were more frequent in children. Among PCR-confirmed positive patients, the distribution of respiratory viral pathogens showed significant variations across different age groups and immune status categories. These findings represent laboratory-based detection trends within a healthcare setting rather than population-level incidence.