Utility of the Xpert Xpress CoV.2/Flu/RSV Plus Kit: A Glance at RSV Infection in Adults and Coinfection Rate

Background: Viral infection is responsible for the majority of respiratory tract infections (RTI). This retrospective study evaluates the advantages of using the multiplex Xpert Xpress CoV-2/Flu/RSV plus kit in laboratory diagnosis of RTI caused by the most related viruses. Materials and Methods: Data were obtained from medical records between November 2021 and May 2023 for any sample tested using either the Xpert Xpress Flu/RSV kit, Xpert Xpress Flu kit, Xpert Xpress SARS-CoV-2 kit, and Xpert Xpress CoV-2/Flu/RSV plus kit. Results: Influenza virus A was detected in 8.5% (55/649) of the samples using the Flu PCR kit and in 4.9% (123/2538) using CoV-2/Flu/RSV plus kit, while influenza virus B detection rates were 3.7% (24/649) using the Flu PCR kit and 1.7% (43/2538) using the CoV-2/Flu/RSV plus kit. However, the detection rates using the two kits were comparable when evaluated for the same time period of the year. SARS-CoV-2 infections were detected in 16.9% (1545/9153) and 10.5% (266/2538) of the cases using the SARS-CoV-2 kit and CoV-2/Flu/RSV plus kits, respectively. Respiratory syncytial virus (RSV) was identified in 17.7% (66/372) of children using Flu/RSV kit; this number dropped significantly when age-targeted testing of RSV was performed due to involvements of adults. With the CoV-2/Flu/RSV plus kit, about 34% (35/103) of RSV infections detected were in patients aged >20 years; these cases would have previously been overlooked because adults are not routinely tested for RSV using the Flu/RSV kit. All coinfection cases (n = 16) were only detected with the CoV-2/Flu/RSV plus kit. Conclusion: The use of Xpert Xpress CoV-2/Flu/RSV plus kit not only results in shorter turnaround times through accurate detection of all four viruses, but also provides information on RSV infection in adults and coinfection rates.