Respiratory syncytial virus outbreak in a tertiary hospital Neonatal Intensive Care Unit

Abstract

[Introduction] Investigation and control of a respiratory syncytial virus (RSV) outbreak that affected the Neonatal Intensive Care Unit (NICU) of a university hospital from October to December 2012.

[Patients and methods] Cohort study of children admitted to the NICU. The infection attack rate was calculated. A descriptive analysis of the cases and a multivariate analysis was performed using the variables that were shown to be risk factors for RSV infection.

Preventive measures taken were: contact isolation; hand hygiene training and observation; exclusivity of a health team of nurses and physicians for positive cases, restrictions on visitor numbers; surveillance RSV testing, and palivizumab prophylaxis. [Results] The outbreak had three epidemic waves and 20 positive cases out of a total of 48 children admitted. The overall attack rate was 42%. Half of positive cases were children, with a median age of 36 days (p25 = 22, p75 = 58). The independent risk factors for RSV infection were birth weight below 1000 grams (OR = 23.5; P=.002) and to have another nosocomial infection the week before the diagnosis of RSV infection (OR = 19.98; P=.016). [Conclusions] It was an outbreak with a high number of cases, due to the delay in notification, prolonged RSV carrier status, and low adherence to hand hygiene practice, which favoured the cross-transmission of infection. The most effective preventive measures were direct observation of hand hygiene and supervision of isolation measures.

[Patients and methods] Cohort study of children admitted to the NICU. The infection attack rate was calculated. A descriptive analysis of the cases and a multivariate analysis was performed using the variables that were shown to be risk factors for RSV infection.

Preventive measures taken were: contact isolation; hand hygiene training and observation; exclusivity of a health team of nurses and physicians for positive cases, restrictions on visitor numbers; surveillance RSV testing, and palivizumab prophylaxis. [Results] The outbreak had three epidemic waves and 20 positive cases out of a total of 48 children admitted. The overall attack rate was 42%. Half of positive cases were children, with a median age of 36 days (p25 = 22, p75 = 58). The independent risk factors for RSV infection were birth weight below 1000 grams (OR = 23.5; P=.002) and to have another nosocomial infection the week before the diagnosis of RSV infection (OR = 19.98; P=.016).

[Conclusions] It was an outbreak with a high number of cases, due to the delay in notification, prolonged RSV carrier status, and low adherence to hand hygiene practice, which favoured the cross-transmission of infection. The most effective preventive measures were direct observation of hand hygiene and supervision of isolation measures.

[Introducción] Investigación y control de un brote por virus respiratorio sincitial (VRS) que afectó a la Unidad de Neonatología (UN) de un hospital universitario de octubre a diciembre del 2012.

[Pacientes y métodos] Estudio de cohortes de los niños ingresados en la UN. Se calculó la tasa de ataque de infección y se realizaron un análisis descriptivo de los casos y un análisis multivariante de aquellas variables que mostraron ser factores de riesgo de infección por VRS.

Las medidas preventivas llevadas a cabo fueron: aislamiento de contacto de casos; formación y observación de higiene de manos; exclusividad del personal sanitario para casos, restricción de visitas; estudio de portadores de VRS y profilaxis con palivizumab.

[Resultados] El brote tuvo 3 ondas epidémicas y un total de 20 casos, de 48 niños ingresados. La tasa de ataque global fue del 42%. De los casos, la mitad fueron niños, con una edad mediana de 36 días (p25 = 22, p75 = 58). El peso al nacimiento inferior a 1.000 g (OR = 23,5; p = 0,002) y tener otra infección nosocomial en la semana previa al diagnóstico de infección por VRS (OR = 19,98; p = 0,016), fueron factores de riesgo independientes de infección por VRS.

[Conclusiones] Se trató de un brote epidémico con un elevado número de casos, relacionado con el retraso en la notificación, el tiempo prolongado del estado de portador del VRS y los fallos en el cumplimiento de la higiene de manos, que favoreció la transmisión cruzada de la infección. Las medidas preventivas más eficaces fueron la observación directa de higiene de manos y supervisión de las medidas de aislamiento.