American Journal of Infection Control 42 (2014) 991-5
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American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Nosocomial respiratory syncytial virus infections in the palivizumab-prophylaxis era with implications regarding high-risk infants Liat Ashkenazi-Hoffnung MD a, b, *, Miri Dotan BSc a, b, Gilat Livni MD b, c, Jacob Amir MD a, b, Efraim Bilavsky MD a, b a b c
Department of Pediatrics C, Schneider Children’s Medical Center, Petach Tikva, Tel Aviv, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Department of Pediatrics A, Schneider Children’s Medical Center, Petach Tikva, Tel Aviv, Israel
Key Words: Bronchiolitis Infection control Health careeassociated infections Infants Palivizumab
Background: Although respiratory syncytial virus (RSV) infection continues to be a leading cause of infant hospitalization with a high transmission rate, recent data on nosocomial RSV infection are scarce. This study investigated the clinical and epidemiologic characteristics of nosocomial RSV infection in the palivizumab-prophylaxis era. Methods: The database of a tertiary pediatric medical center was searched for all hospitalized patients with RSV-positive respiratory disease in 2008-2010. Data were compared between patients with community-associated and nosocomial disease, and the qualiﬁcation of the latter group for palivizumab was evaluated. Results: Of the 873 children identiﬁed, 30 (3.4%) had a nosocomial infection. This group accounted for 0.06% of all admissions during the study period. The nosocomial infection group had higher rates of preterm birth and severe underlying disease than the community-associated RSV group and a longer mean hospital stay. The nosocomial infection group also had higher rates of intensive care unit admission and mechanical ventilation. Although 73% had underlying conditions, most (80%) did not qualify for RSV immunoprophylaxis, including 7 children (23%) with immune deﬁciency. Conclusion: Nosocomial RSV infection is a signiﬁcant cause of morbidity among hospitalized infants, especially those with comorbidities and lengthy hospital stay, and is associated with a complicated clinical course. In addition to strict infection-control measures, extending palivizumab prophylaxis to additional selected high-risk populations should be considered. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Respiratory syncytial virus (RSV) is the single most important virus causing acute respiratory tract infections in infants and young children.1 Shortly after its identiﬁcation,2,3 outbreaks of nosocomial RSV infection were recognized.4,5 Since then, there have been several reports involving neonatal intensive care units6-8 and pediatric intensive care units (PICUs),9,10 where nosocomial RSV infection may be particularly severe, with high mortality rates. Nevertheless, the exact prevalence remains unclear because reported rates vary widely.11-19
Palivizumab, a humanized mouse monoclonal antibody, is used in the prevention of RSV infections. Its administration in selected high-risk infants has reduced hospital admissions caused by the disease.20 However, nosocomial RSV infections were not studied under the current RSV prophylaxis recommendations. The aim of the present study was to investigate the clinical and epidemiologic characteristics of nosocomial RSV infections in the palivizumabprophylaxis era, including potential changes in preexisting risk factors, symptomatology, illness severity, and outcome.
* Address correspondence to Liat Ashkenazi-Hoffnung, MD, Department of Pediatrics C, Schneider Children’s Medical Center, 14 Kaplan St, Petach Tikva 49202, Israel. E-mail address: [email protected]
(L. Ashkenazi-Hoffnung). This research was part of the MD-thesis of Miri Dotan, Sackler Medical School, Tel Aviv University. Conﬂicts of interest and Source of funding: None.
METHODS The database of a tertiary pediatric medical center was searched for all patients hospitalized between January 1, 2008, and December 31, 2010, with laboratory-conﬁrmed RSV infection. The medical records of the individual patients were reviewed, and a
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L. Ashkenazi-Hoffnung et al. / American Journal of Infection Control 42 (2014) 991-5
standardized data set was extracted as follows: date of birth, gestational age at birth, sex, birth weight, admission and discharge dates, readmission date, dates of RSV testing, presence of recurrent wheezing, presence of severe underlying disease requiring medical therapy (eg, chronic lung disease [CLD], congenital heart disease [CHD], primary or secondary immune deﬁciency), temperature, chest radiograph ﬁndings, laboratory results, steroid and betaagonist use, oxygen requirement, PICU admission, mechanical ventilation, and bacterial cultures obtained. We also recorded the use of palivizumab prior to hospitalization and the qualiﬁcation of infants with nosocomial RSV infection for palivizumab prophylaxis according to the latest recommendations of the American Academy of Pediatrics (AAP).21 Given the usual 3-5 day incubation period for RSV infection,22 as previously deﬁned in studies in the literature,10,11,14,17,23 the disease was assumed to have originated in hospital when RSV-positive respiratory symptoms appeared 5 days after hospitalization in a patient who was known to be RSV negative on admission or who had not undergone sampling on admission because no respiratory symptoms or signs were present. A nosocomial infection was also diagnosed in patients readmitted within 5 days of previous hospital discharge because of respiratory symptoms and an RSV-positive respiratory specimen. Similarly, during the ﬁrst hospitalization of these patients, RSV testing was negative or was not done because there were no respiratory complaints. Each case was reviewed by a pediatric infectious disease specialist. All other hospitalizations were deﬁned as community-associated RSV infection. Testing for RSV infection at our center was performed with a commercial enzyme-linked immunoassay membrane test for the rapid and qualitative detection of RSV antigen directly from nasopharyngeal specimens (RSV Respi-Strip; Coris BioConcept, Gembloux, Belgium; in comparison with cell culture and reverse transcriptase polymerase chain reaction, the sensitivity of this test is 91% and the speciﬁcity is 98%).24
Infection control policy The RSV infection control policy in the general pediatric wards in our center is based on contact precautions. All hospitalized patients found to have clinical bronchiolitis, microbiologically conﬁrmed or not, are placed in separate rooms at the onset of symptoms and undergo RSV testing. Those with positive results are further segregated. During the RSV season, all the patients with a respiratory complaint, even a mild one (eg, upper respiratory tract infection), are tested for RSV. All health care workers wear protective clothing consisting of a disposable apron, gloves, and face masks during exposure to the body ﬂuids of an infected patient (eg, suctioning). Hands are washed before and after any contact with the patient. The environment is cleaned daily with a chlorine-releasing agent, and the room is disinfected after discharge.
Statistical analysis Two-tailed t test or the nonparametric Mann-Whitney U test was used, as appropriate, to compare continuous variables between patients with nosocomial and community-associated RSV infection. Pearson c2 test was used to compare categorical variables, with continuity correction. A P value .05 was deﬁned a priori as statistically signiﬁcant. The study protocol was approved by the institutional review board and ethics committee.
Table 1 Clinical characteristics of children with RSV infection
Clinical feature Sex (male:female) Age at admission, mean SD (months) Age distribution, n (%) Newborn (