Implementation of influenza point-of-care testing and patient cohorting during a high-incidence season: a retrospective analysis of impact on infection prevention and control and clinical outcomes

Abstract

During high-incidence influenza seasons, a robust infection prevention and control policy is imperative to reduce nosocomial transmission of influenza. To assess the impact of influenza point-of-care testing (POCT) in an emergency department (ED) and patient cohorting on an influenza ward on infection prevention and control and clinical outcomes. Influenza POCT was operational in the study ED from 21st January 2018 and patient cohorting was operational on an influenza ward from 25th January 2018. A retrospective 'before-after' analysis was performed with pre-intervention defined as 1st November 2017 to 20th January 2018 and post-intervention defined as 21st January 2018 to 30th April 2018. The primary outcome was the rate of hospital-acquired influenza. Secondary outcomes included antiviral prescription and length of stay. The length of time that inpatients remained influenza-positive was estimated by polymerase chain reaction (PCR). There were 654 inpatients with confirmed influenza during the 2017/18 influenza season: 223 pre- and 431 post-intervention. Post-intervention, there were fewer cases of hospital-acquired influenza per day (0.66 vs 0.95, P<0.0001), median length of stay was shorter (5.5 vs 7.5 days, P=0.005) and antiviral prescription was more frequent (80% vs 64.1%, P<0.0001). Cohorting released 779 single rooms for use elsewhere in the trust. The fixed probability of being PCR-negative by the next day (P) was 0.14 [95% confidence interval (CI) 0.12-0.16] for immunocompetent patients. This implies that half of immunocompetent patients are PCR-negative by five days post-diagnosis (95% CI 5-6). Influenza POCT in an ED and patient cohorting on an influenza ward were associated with reduced nosocomial transmission of influenza and improved patient flow. A policy of retesting immunocompetent patients five days post-diagnosis could allow half of these patients to come out of respiratory isolation earlier.