Respiratory viral co-infections in patients with COVID-19 and associated outcomes: A systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to critically assess the published literature related to community-acquired viral co-infections and COVID-19 and to evaluate the prevalence, most identified co-pathogens, and relevant risk factors. Furthermore, we aimed to examine the clinical features and outcomes of co-infected compared to mono-infected COVID-19 patients. We systematically searched PubMed, Web of Science, Embase, Scopus, and The Cochrane Library for studies published from 1 November 2019 to 13 August 2021. We included patients of all ages and any COVID-19 severity who were screened for respiratory viral co-infection within 48 h of COVID-19 diagnosis. The main outcome was the proportion of patients with a respiratory viral co-infection. The systematic review was registered to PROSPERO (CRD42021272235). Out of 6053 initially retrieved studies, 59 studies with a total of 16,643 SARS-CoV-2 positive patients were included. The global pooled prevalence was 5.01% (95% CI 3.34%–7.27%; I² = 95%) based on a random-effects model, with Influenza Viruses (1.54%) and Enteroviruses (1.32%) being the most prevalent pathogens. Subgroup analyses showed that co-infection was significantly higher in paediatric (9.39%) than adult (3.51%) patients (p-value = 0.02). Furthermore, co-infected patients were more likely to be dyspnoeic and the odds of fatality (OR = 1.66) were increased. Although a relatively low proportion of COVID-19 patients have a respiratory viral co-infection, our findings show that multiplex viral panel testing may be advisable in patients with compatible symptoms. Indeed, respiratory virus co-infections may be associated with adverse clinical outcomes and therefore have therapeutic and prognostic implications.