Respiratory syncytial virus outbreak on an adult stem cell transplant unit

- Strict infection control measures are required to terminate an RSV outbreak.
- Other viruses of outbreak potential may be detectable among health care workers.
- RSV-B may be less virulent than RSV-A among immunocompromised adults.

BackgroundAn increase in respiratory syncytial virus type B (RSV-B) infections was detected on an adult hematology/oncology and stem cell transplant unit during March 2015. This prompted an outbreak investigation.MethodsNosocomial cases were defined as RSV-B-positive patients who developed respiratory virus symptoms ≥ 7 days after admission to the unit or were readmitted with symptoms ≤ 7 days since last discharge from the unit. Strict outbreak control measures were implemented to stop the outbreak.ResultsDuring the outbreak, 19 cases of RSV-B were detected, 14 among patients and 5 among health care workers (HCWs). Additionally, 2 HCWs tested positive for respiratory syncytial virus type A and 1 tested positive for influenza B among the 27 symptomatic HCWs evaluated. No specific antiviral therapy was given and all cases recovered without progression to lower respiratory tract infection. After no new cases were identified for 2 weeks, the outbreak was declared over.ConclusionsHigh vigilance for respiratory viruses on high-risk inpatient units is required for detection and prevention of potential outbreaks. Multiple respiratory viruses with outbreak potential were identified among HCWs. HCWs with respiratory virus symptoms should not provide direct patient care. Absence of lower respiratory tract infection suggests lower virulence of RSV-B, compared with respiratory syncytial virus type A, among immunocompromised adults.