Detection of Respiratory Viruses Other Than SARS-CoV-2 in a Large Hospital Laboratory in Rome, Italy, During the Seasons 2016–2017 to 2022–2023

Background and Objective

Respiratory viruses are major contributors to morbidity and mortality worldwide, with their circulation influenced by seasonal patterns and pandemic-related interventions. This study analyzed detection trends of non-SARS-CoV-2 respiratory viruses in a large Italian hospital over a 7-year period, focusing on variations across COVID-19–related periods and patient age groups.

Methods

We retrospectively analyzed multiplex PCR-based laboratory results of 8836 nasopharyngeal samples collected between September 2016 and August 2023. Viral detection rates were stratified by season, COVID-19–related periods (pre-pandemic, pandemic, post-pandemic), and age groups.

Results

Of the 8836 nasopharyngeal samples analyzed, 2795 (31.6%) tested positive for at least one respiratory virus. Rhinovirus/enterovirus (RV/EV) was the most frequently detected virus (37.6%), followed by influenza A virus (IAV, 17.9%) and respiratory syncytial virus (RSV, 17.2%). The 2020–2021 season had the lowest positivity rate (p < 0.001), with marked declines in IAV and RSV detections, likely because of COVID-19 mitigation measures. Conversely, detections of RV/EV and human coronaviruses increased. Postpandemic data suggested a return to prepandemic patterns, though overall positivity rates remained altered. Age-stratified analysis revealed RSV predominance in infants (p < 0.001), emphasizing its clinical relevance in pediatric populations.

Conclusions

Our findings highlight the dynamic nature of respiratory virus epidemiology and the persistent impact of the COVID-19 pandemic on viral circulation. Continuous surveillance and adaptive public health strategies are essential for managing future outbreaks and mitigating the burden of respiratory viral infections.