The use of palivizumab monoclonal antibody to control an outbreak of respiratory syncytial virus infection in a special care baby unit

Respiratory syncytial virus nosocomial outbreak in neonatal intensive care: A review of the incidence, management, and outcomes

BACKGROUND

The main objective was to determine the incidence, management, and outcomes of respiratory syncytial virus nosocomial infection (RSVNI) outbreaks in neonatal intensive care units.

METHODS

A comprehensive search of RSVNI in 9 databases was conducted from January 1, 2000 to May 1, 2021, of which the Cochrane Library comprised the Cochrane central register of controlled trials and the Cochrane database of systematic reviews. Two hundred and twenty-eight articles were retrieved and 17 were retained. A descriptive analysis was performed, and frequencies are reported as mean, median, and range where pertinent.

RESULTS

One hundred and seventeen infants were analyzed and comprised preterms (88.1%) and those with pre-existing co-morbidities. The estimated proportional incidence of RSVNI was 23.8% (177/744) infants. Outbreaks were principally managed by conventional protective measures, neonatal intensive care unit closure, and visitor restriction. Palivizumab was used to control RSVNI in 10 studies. RSVNI-related mortality was 8.5% (15/177) and 8.0% (7/87) among infants where infection control was solely employed.

CONCLUSION

RSVNI is associated with significant morbidity and mortality. The use of palivizumab should be a multidisciplinary decision, based on rapidly spreading infection. Prospective studies are essential to determine the cost-benefit of palivizumab versus standard prevention control for an RSVNI outbreak.

An outbreak of RSV infections in a neonatology clinic during the RSV-season

BACKGROUND

Respiratory syncytial virus (RSV) is the predominant cause of lower respiratory tract infections (LRTI) in infancy. Preterm infants with bronchopulmonary dysplasia (BPD) are at the highest risk of severe RSV-LRTI. This is a retrospective study that analyses a nosocomial outbreak of RSV infections in the Neonatology clinic of the University Hospital of Obstetrics and Gynecology, Sofia, 2019.

METHODS

Two groups of infants without contact between them were diagnosed with RSV-infection: 14 infants were treated in the Department for healthy newborns - Group 1, and 7 preterm infants were treated in the Neonatal Intensive Care Unit (NICU) - Group 2. The detection of RSV was performed using Real-Time PCR in nasal/throat swabs.

RESULTS

Respiratory symptoms occurred 2-5 days after discharge in 14 of 148 healthy term infants born February 5 to 18, 2019; 12 babies were re-hospitalized with LRTI and recovered in a few days. RSV-PCR was positive in 6 infants, while in the others, RSV etiology was suggested, due to similar symptoms and contact between them. The first NICU patient with RSV-LRTI was one of the 26 gestational weeks (GW) twins, who had severe BPD. The other twin was always discharged home without LRTI-symptoms. In the period February 19 to March 15, 2019, 26 premature babies born at 26-34 GW, were tested for RSV (33 nasal/throat swabs). They received a first or subsequent palivizumab injection. We identified 11 positive samples in 7 of the babies. Despite the clinical recovery, the second RSV-PCR remained positive in 4 babies. Six of the 7 NICU patients had symptoms of LRTI, and two of them needed mechanical ventilation. Six babies were discharged home after stabilization, one was transferred to the Pediatric department for further treatment of BPD and later discharged too.

CONCLUSIONS

This was the most serious outbreak of RSV infections in neonates since the RSV-PCR diagnostic in Bulgaria was introduced. The course of RSV-LRTI was severe in extremely preterm patients with underlying BPD. So, routine in-hospital RSV-prophylaxis with palivizumab should be considered for infants at the highest risk.

Multiple Respiratory Syncytial Virus Introductions Into a Neonatal Intensive Care Unit

BACKGROUND

Outbreaks of respiratory syncytial virus (RSV) in neonatal intensive care units (NICUs) are of concern because of the risk of severe disease in young infants. We describe an outbreak of RSV in a NICU and use whole genome sequencing (WGS) to better understand the relatedness of viruses among patients.

METHODS

An investigation was conducted to identify patients and describe their clinical course. Infection control measures were implemented to prevent further spread. Respiratory specimens from outbreak-related patients and the community were tested using WGS. Phylogenetic trees were constructed to understand relatedness of the viruses.

RESULTS

Seven patients developed respiratory symptoms within an 11-day span in December 2017 and were diagnosed with RSV; 6 patients (86%) were preterm and 1 had chronic lung disease. Three patients required additional respiratory support after symptom onset, and none died. Six of 7 patients were part of the same cluster based on > 99.99% nucleotide agreement with each other and 3 unique single-nucleotide polymorphisms were identified in viruses sequenced from those patients. The seventh patient was admitted from the community with respiratory symptoms and had a genetically distinct virus that was not related to the other 6. Implementation of enhanced infection control measures likely limited the spread.

CONCLUSIONS

Using WGS, we found 2 distinct introductions of RSV into a NICU, highlighting the risk of healthcare-associated infections during RSV season. Early recognition and infection control measures likely limited spread, emphasizing the importance of considering RSV in the differential diagnosis of respiratory infections in healthcare settings.

Overcrowding in a neonatal intermediate care unit: impact on the incidence of multidrug-resistant gram-negative organisms

BACKGROUND

Overcrowding, reduced nurse to patient ratio, limited distance between incubators and absence of microbiological surveillance have been shown to promote spread of multidrug-resistant gram-negative organisms (MDRGN) in patients with birthweight < 1500 g. Patients > 1500 g treated on an intermediate care unit are unrepresented in recent literature. We therefore intended to present data obtained from a short-term overcrowded neonatal intermediate care unit (NIMCU) at a level III (international categorization) perinatal center at University Hospital Frankfurt, Germany.

METHODS

During a 25 day overcrowding (OV) and 28 day post-overcrowding period (POST-OV) on NIMCU, epidemiological data obtained from continuously hold microbiological surveillance were investigated and compared to the last 12 months of ward-regular bed occupancy preceding OV (PRAE-OV).

RESULTS

During OV, the number of patients simultaneously treated at the NIMCU increased from 18 to 22, resulting in a reduced bed-to-bed space. Nurse: patient ratio was 4:22 during OV compared to 3:18 during PRAE-OV. Cumulative incidence of MDRGN was 4.7% in OV and 2.4% POST-OV compared to 4.8% to PRAE-OV, respectively, without any significant variations. During OV and POST-OV, septic episodes due to MDRGN were not observed. In one case, potential nosocomial transmission of Enterobacter cloacae resistant to Piperacillin and 3rd/4th generation cephalosporins was observed.

CONCLUSIONS

Prevention of nosocomial spread of MDRGN in an overcrowded NIMCU is based on staff's diligent training and adequate staffing. Concise microbiological surveillance should be guaranteed to escort through overcrowding periods. In our setting, impact of bed-to-bed distance on MDRGN transmission seemed to be less strong.

Use of palivizumab with other infection control measures to control respiratory syncytial virus outbreaks in neonatal care units

OBJECTIVE

No guidelines exist on the use of palivizumab during outbreaks of Respiratory Syncytial Virus (RSV) in Neonatal Intensive Care Units (NICUs). We aimed to describe an outbreak of RSV in NICU settings and the role of palivizumab in controlling the outbreak.

METHODS

The index case was a 30-day-old premature infant. During the outbreak, 13 cases of RSV were confirmed by RT-PCR. All infants in the NICU received palivizumab after RSV diagnosis.

RESULTS

Of the 13 cases, seven were male; and the median (interquartile) of birth weight was 1585 (IQR: 1480-1705) g. All cases were premature under 34-weeks-gestation. Age at onset of disease varies between 10 and 160 days. Only four cases occurred after administering palivizumab and applying other infection control measures.

CONCLUSION

During nosocomial outbreaks of RSV, administration of palivizumab to all infants in NICU appears to be rational and may help contain outbreaks.

Risk of nosocomial respiratory syncytial virus infection and effectiveness of control measures to prevent transmission events: a systematic review

Respiratory syncytial virus (RSV) causes a significant public health burden, and outbreaks among vulnerable patients in hospital settings are of particular concern. We reviewed published and unpublished literature from hospital settings to assess: (i) nosocomial RSV transmission risk (attack rate) during outbreaks, (ii) effectiveness of infection control measures. We searched the following databases: MEDLINE, EMBASE, CINAHL, Cochrane Library, together with key websites, journals and grey literature, to end of 2012. Risk of bias was assessed using the Cochrane risk of bias tool or Newcastle–Ottawa scale. A narrative synthesis was conducted. Forty studies were included (19 addressing research question one, 21 addressing question two). RSV transmission risk varied by hospital setting; 6–56% (median: 28·5%) in neonatal/paediatric settings (n = 14), 6–12% (median: 7%) in adult haematology and transplant units (n = 3), and 30–32% in other adult settings (n = 2). For question two, most studies (n = 13) employed multi‐component interventions (e.g. cohort nursing, personal protective equipment (PPE), isolation), and these were largely reported to be effective in reducing nosocomial transmission. Four studies examined staff PPE; eye protection appeared more effective than gowns and masks. One study reported on RSV prophylaxis for patients (RSV‐Ig/palivizumab); there was no statistical evidence of effectiveness although the sample size was small. Overall, risk of bias for included studies tended to be high. We conclude that RSV transmission risk varies widely during hospital outbreaks. Although multi‐component control strategies appear broadly successful, further research is required to disaggregate the effectiveness of individual components including the potential role of palivizumab prophylaxis.

Outcome of the Respiratory Syncytial Virus related acute lower respiratory tract infection among hospitalized newborns: a prospective multicenter study

AIM

To determine the incidence and outcomes of respiratory syncytial virus (RSV)-related acute lower respiratory tract infection (ALRI) including morbidity, nosocomial infection and mortality among newborn infants who were admitted to the neonatal intensive care units (NICUs).

METHODS

A multicenter, prospective study was conducted in newborns who were hospitalized with community acquired or nosocomial RSV infection in 44 NICUs throughout Turkey. Newborns with ALRI were screened for RSV infection by Respi-Strip®-test. Main outcome measures were the incidence of RSV-associated admissions in the NICUs and morbidity, mortality and epidemics results related to these admissions.

FINDINGS

The incidence of RSV infection was 1.24% (n: 250) and RSV infection constituted 19.6% of all ALRI hospitalizations, 226 newborns (90.4%) had community-acquired whereas 24 (9.6%) patients had nosocomial RSV infection in the NICUs. Of the 250 newborns, 171 (68.4%) were full-term infants, 183 (73.2%) had a BW >2500 g. RSV-related mortality rate was 1.2%. Four NICUs reported seven outbreaks on different months, which could be eliminated by palivizumab prophylaxis in one NICU.

CONCLUSION

RSV-associated ALRI both in preterm and term infants accounts an important percent of hospitalizations in the season, and may threat other high-risk patients in the NICU.

Nosocomial respiratory syncytial virus infections in the palivizumab-prophylaxis era with implications regarding high-risk infants

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.

Prevention and treatment of respiratory syncytial virus infection in infants: an update

Respiratory syncytial virus (RSV) is a serious pathogen causing significant mortality and morbidity, especially in premature infants and infants with chronic lung disease or significant congenital heart disease. Therapy for RSV infection is essentially supportive, although several new compounds are under investigation. Therefore, immunoprophylaxis to prevent severe RSV disease in high-risk infants assumes great significance. Palivizumab, a humanized monoclonal antibody to RSV, significantly reduces hospitalization in the first 6 months in premature infants born at less than 35 weeks, infants less than 24 months of age with chronic lung disease and requiring treatment in the last 6 months, and in children 24 months or younger with hemodynamically significant heart disease. A new ultrapotent anti-RSV antibody (MEDI-524) appears to be more effective in animals than palivizumab and is undergoing clinical evaluation. There has been considerable progress in the development of vaccines; namely subunit, live attenuated, genetically recombinant virus and polypeptide vaccines. Plasmid DNA vaccines coding for parts of the F and G surface glycoproteins and vaccinia vector vaccines are also being evaluated. Maternal immunization has the potential to prevent RSV disease in early infancy. RSV prophylaxis has seen tremendous progress in the last decade.

Palivizumab prophylaxis during nosocomial outbreaks of respiratory syncytial virus in a neonatal intensive care unit: predicting effectiveness with an artificial neural network model

STUDY OBJECTIVE

To identify subgroups of premature infants who may benefit from palivizumab prophylaxis during nosocomial outbreaks of respiratory syncytial virus (RSV) infection.

DESIGN

Retrospective analysis using an artificial intelligence model.

SETTING

Level IIIB, 35-bed, neonatal intensive care unit (NICU) at a tertiary care hospital in the United Arab Emirates.

PATIENTS

One hundred seventy six premature infants, born at a gestational age of 22-34 weeks, and hospitalized during four RSV outbreaks that occurred between April 2005 and July 2007.

MEASUREMENTS AND MAIN RESULTS

We collected demographic and clinical data for each patient by using a standardized form. Input data consisted of seven categoric and continuous variables each. We trained, tested, and validated artificial neural networks for three outcomes of interest: mortality, days of supplemental oxygen, and length of NICU stay after the index case was identified. We compared variable impacts and performed reassignments with live predictions to evaluate the effect of palivizumab. Of the 176 infants, 31 (17.6%) received palivizumab during the outbreaks. All neural network configurations converged within 4 seconds in less than 400 training cycles. Infants who received palivizumab required supplemental oxygen for a shorter duration compared with controls (105.2 ± 7.2 days vs 113.2 ± 10.4 days, p=0.003). This benefit was statistically significant in male infants whose birth weight was less than 0.7 kg and who had hemodynamically significant congenital heart disease. Length of NICU stay after identification of the index case and mortality were independent of palivizumab use.

CONCLUSION

Palivizumab may be an effective intervention during nosocomial outbreaks of RSV in a subgroup of extremely low-birth-weight male infants with hemodynamically significant congenital heart disease.

Respiratory syncytial virus outbreak in neonatal intensive care unit: Impact of infection control measures plus palivizumab use

BACKGROUND

The occurrence of a respiratory syncytial virus (RSV) outbreak in a Neonatal Intensive Care Unit (NICU) is related to unfavorable outcomes, as this infection can lead to respiratory distress and death in premature in infants. Report the successful control of an outbreak that occurred in April 2010 in a NICU.

METHODS

After the index case, of 18 premature infants placed in the same room 10 infants were infected. Of those 10, 6 developed mild to moderate respiratory symptoms, 4 persisted asymptomatic and no death occurred. Contact and respiratory precautions were rapidly initiated, the infants were cohorted in 3 different rooms and palivizumab was administered to all contacts.

RESULTS

The outbreak was controlled and no new cases were subsequently indentified.

CONCLUSION

Standard infection control measures plus palivizumab prophylaxis were efficient in rapid control of the outbreak.

Use of palivizumab and infection control measures to control an outbreak of respiratory syncytial virus in a neonatal intensive care unit confirmed by real-time polymerase chain reaction

Respiratory syncytial virus (RSV) is a potentially life-threatening infection in premature infants. We report an outbreak involving four infants in the neonatal intensive care unit (NICU) of our hospital that occurred in February 2010. RSV A infection was confirmed by real-time polymerase chain reaction. Palivizumab was administered to all infants in the NICU. There were no additional symptomatic cases and repeat RSV surveillance confirmed that there was no further cross-transmission within the unit. The outbreak highlighted the infection control challenge of very high bed occupancy in the unit and the usefulness of molecular methods in facilitating detection and management.

Detection and control of a nosocomial respiratory syncytial virus outbreak in a stem cell transplantation unit: the role of palivizumab

Respiratory syncytial virus (RSV) is a common community-acquired virus that causes upper and lower respiratory tract infections in children, hematologic malignancy patients, and hematopoietic stem cell transplant (HSCT) recipients. Nosocomial transmission of RSV in immunocompromised patients can significantly affect morbidity, mortality, and duration of hospitalization. Stringent infection control measurements are needed to control further hospital transmission. Prophylactic palivizumab was found to result in a significant reduction in hospitalization rates in high-risk children. In this article, we report a nosocomial outbreak of RSV in an adult HSCT unit (4 pods) from January 16 to February 4, 2004, including the infection control interventions used and the prophylactic administration of palivizumab in high-risk patients. Active surveillance identified 5 cases, a substantial increase from previous seasons (2 or 3 cases per season). All infected patients were isolated to 1 nursing pod and placed on contact isolation. All patients on the HSCT unit underwent rapid RSV antigen screening using nasal washes; this was repeated 1 week later, and 1 additional RSV case was identified. Patients identified to be at increased risk for RSV infection received prophylactic palivizumab. Routine screenings of the staff and visitors were undertaken. All patient and visitor areas were thoroughly cleaned with bleach. We educated health care workers about RSV transmission, highlighting proper hand hygiene and contact precautions. Four of 6 patients with RSV infection developed RSV pneumonia, and 2 of these patients died. Staff and visitors with upper respiratory symptoms were screened, and all were negative for RSV. Prophylactic palivizumab was administered in 16 patients who tested negative for RSV, but were considered to be at increased risk for RSV infection. None of these patients developed RSV infections. An RSV outbreak was controlled using prompt preventive measures, including cohorting patients, with a dedicated health care staff; contact isolation of patients; strict adherence to hand hygiene; and screening of visitors, family members, and health care staff for upper respiratory infection symptoms. Immunoprophylaxis with palivizumab, administered to high-risk patients, complemented strict infection control intervention. Thus, the role of palivizumab in the control of RSV hospital outbreaks merits further investigation.

[Consensus conference on acute bronchiolitis (v): prevention of acute bronchiolitis. Review of scientific evidence]

A review of the evidence on prevention of acute bronchiolitis is presented. Acute bronchiolitis prevention arises from three basic approaches: preventive treatment to reduce recurrent wheezing following an episode of acute bronchiolitis, preventive treatment to reduce the frequency and severity of RSV bronchiolitis in the population at risk (prematurity, bronchopulmonary dysplasia, congenital heart disease, etc.), and general preventive measures to reduce nosocomial infection with RSV. There is sufficient evidence on the lack of efficacy of inhaled corticosteroids, oral corticosteroids and montelukast. Intravenous RSV immunoglobulin has an unfavorable risk-benefit balance, particularly with the availability of monoclonal antibodies. Palivizumab is effective as preventive treatment of RSV infection in risk populations (high risk preterm infants and hemodynamically significant congenital heart disease), but not in the frequency and severity (ICU admission, need for mechanical ventilation and mortality) of the acute bronchiolitis. The benefits of palivizumab (less admissions) seem to be worth the adverse effects, but we do not know the cost-benefit ratio. The control and prevention measures of nosocomial transmission of RSV infection (isolation, hand washing, use of mask, gloves, cap and shoes) are based on indirect evidence.

Respiratory syncytial virus outbreak defined by rapid screening in a neonatal intensive care unit

Palivizumab is currently licensed for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in infants and children with chronic lung disease, with a history of preterm birth, or with haemodynamically significant congenital heart disease, but its routine use during outbreaks in neonatal intensive care units (NICUs) is not currently recommended. Here we report an outbreak in a NICU detected during a screening trial for RSV infection using a rapid antigen test (Respi-Strip^®). Eleven preterm infants in our NICU tested positive for RSV during January 2009. Subsequent testing of the remaining infants in the NICU revealed two additional asymptomatic cases. In addition to precautions against cross-infection, palivizumab prophylaxis was administered to the remaining 37 premature infants. Two days after treatment, RSV was detected in two additional infants who had become symptomatic. To our knowledge this is the largest RSV outbreak in a NICU to be identified at an early stage by rapid testing and effectively controlled by infection control measures and palivizumab prophylaxis.

Respiratory syncytial virus prophylaxis in a tertiary care neonatal intensive care unit

Nosocomial transmission of respiratory syncytial virus (RSV) is a serious, preventable cause of RSV infection. Passive RSV prophylaxis became available in 1996. We compared the RSV nosocomial infection rate in our neonatal intensive care unit before and after RSV prophylaxis, using nosocomial rotavirus infections as a comparator. There were no significant differences between nosocomial RSV infection rates before and after institution of prophylaxis.

Experience with the use of palivizumab together with infection control measures to prevent respiratory syncytial virus outbreaks in neonatal intensive care units

Respiratory syncytial virus (RSV) frequently causes nosocomial outbreaks in general paediatric wards and occasionally in neonatal intensive care units (NICUs). Conventional infection control measures often fail to prevent the spread of RSV, and it can cause significant morbidity especially in preterm and young infants. We report our experience in preventing an outbreak on a NICU after RSV had been detected in a premature infant. The index case was a 34-day-old premature infant who presented with clinical infection and RSV was detected in a clinical specimen. There were 11 patients in the ward at the time including the index case. The RSV-positive patient was isolated, the ward closed to admissions and infection control measures were implemented. Two patients were transferred to another hospital. Palivizumab 15 mg/kg i.m. was given to all patients and no further cases occurred. All subsequent RSV tests on nasal secretions were negative. Palivizumab combined with conventional infection control measures appeared to prevent the spread of RSV in this NICU. Strategies for the prevention of RSV outbreaks on NICUs all recommend the reinforcement of routine infection control measures. Recommendations concerning the use of palivizumab range from monthly prophylaxis to all infants at risk, to prophylaxis of selected cases only. Currently there are no guidelines for the use of palivizumab in NICUs or for the control of RSV outbreaks.

Nosocomial infection: A risk factor for a complicated course in children with respiratory syncytial virus infection – Results from a prospective multicenter German surveillance study

BACKGROUND

Nosocomially acquired respiratory syncytial virus infections (RSV-NI) may cause serious problems in hospitalized paediatric patients. Hitherto, prospectively collected representative data on RSV-NI from multicenter studies in Germany are limited.

METHODS

The DMS RSV Ped database was designed for the prospective multicenter documentation and analysis of clinically relevant aspects of the management of inpatients with RSV-infection. The study covered six consecutive seasons (1999-2005); the surveillance took place in 14 paediatric hospitals in Germany.

RESULTS

Of the 1568 prospectively documented RSV-infections, 6% (n=90) were NI and 94% (n=1478) were community acquired (CA). A significantly higher proportion in the NI group displayed additional risk factors like prematurity, chronic lung disease, mechanical ventilation (med. history), congenital heart disease, and neuromuscular impairment. Of all NI, 55% occurred in preterms (30.6% of all RSV-infections in preterms with severe chronic lung disease of prematurity were NI). Illness severity as well as the total mortality, but not the attributable mortality was significantly higher in the NI group. In the multivariate analysis, NI was significantly associated with the combined outcome 'complicated course of disease'.

CONCLUSION

This is the first prospective multicenter study from Germany, which confirms the increased risk of a severe clinical course in nosocomially acquired RSV-infection. Of great concern is the high rate of (preventable) NI in preterms, in particular in those with severe chronic lung disease or with mechanical ventilation due to other reasons.

Strategies for prevention of RSV nosocomial infection

OBJECTIVE

To review the literature on respiratory syncytial virus (RSV) as a cause of nosocomial infections (NI) on neonatal intensive care units (NICUs) and pediatric wards, and the effectiveness of various containment strategies.

STUDY DESIGN

We conducted a literature review to define characteristics of RSV NI, and to evaluate the relative effectiveness of various infection containment programs, including the use of palivizumab on the reported incidence of RSV NI on NICUs and pediatric wards.

RESULT

Highly variable rates of RSV NI have not significantly changed since RSV was first identified. The evaluation of the effectiveness of containment strategies has relied on before/after study designs. Focus on rapid patient diagnosis, compliance of acceptable handwashing techniques and cohorting of patients and staff appears to form the backbone of most prevention and containment programs. When these or other measures have failed, the administration of palivizumab has been useful in halting the spread of RSV NI in children.

CONCLUSION

RSV NI continues to be prevalent in the NICU despite adoption of infection control programs. Preventive measures should be employed to lower the risk of RSV NI and, if identified, appropriate containment strategies should be rapidly implemented.

Sensitive commercial NASBA assay for the detection of respiratory syncytial virus in clinical specimen

The aim of the study was to evaluate the usability of three diagnostic procedures for the detection of respiratory syncytial virus in clinical samples. Therefore, the FDA cleared CE marked NOW® RSV ELISA, the NucliSENS® EasyQ RSV A+B NASBA, and a literature based inhouse RT-PCR protocol were compared for their relative sensitivities. Thereby, NASBA turned out to be the most sensitive method with a total number of 80 RSV positive samples out of a cohort of 251 nasopharyngeal washings from patients suffering from clinical symptoms, followed by the inhouse RT-PCR (62/251) and ELISA (52/251). Thus, NASBA may serve as a rapid and highly sensitive alternative for RSV diagnostics.

Respiratory syncytial virus infection in 406 hospitalized premature infants: results from a prospective German multicentre database

Premature birth, chronic lung disease of prematurity (CLD), congenital heart disease and immunodeficiency predispose to a higher morbidity and mortality in respiratory syncytial virus (RSV) infection. This study describes the preterms hospitalised with RSV infection from the prospective German DSM RSV Paed database. The DMS RSV Paed database was designed for the prospective multicentre documentation and analysis of clinically relevant aspects of the management of inpatients with RSV infection. This study covers six consecutive RSV seasons (1999-2005); the surveillance took place in 14 paediatric hospitals in Germany. Of the 1,568 prospectively documented RSV infections, 26% (n=406) were observed in preterms [vs. 1,162 children born at term (74%)] and 3% (n=50) had CLD, of which 49 had received treatment in the last 6 months ('CLDplus'). A significantly higher proportion in the preterm group had congenital heart disease, nosocomial infection, and neuromuscular impairment. There were significantly more children older than 24 months in the preterm group. The attributable mortality was 0.2% (n=2) in children born at term vs. 1.2% (n=5) in the preterm group (p=0.015) [preterm plus CLD 8.0% (n=4 of 50); McIntosh grade 1, 8.6% (n=3 of 35) and McIntosh Grade 4, 15% (n=3 of 20)]. Eight patients were categorized as 'palivizumab failures'. In the multivariate analysis, premature birth, CLD(plus), and nosocomial infection were significantly and independently associated with the combined outcome 'complicated course of disease'. In conclusion, this is the first prospective multicentre study from Germany that confirms the increased risk for severe RSV disease in preterms, in particular in those with CLD treated in the last 6 months before the onset of the infection. From the perspective of our results, the statements of the German Society of Paediatric Infectious Diseases considering the use of passive immunisation (2003) seem reasonable.

Healthcare-associated infections in neonatal units: lessons from contrasting worlds

Neonatal intensive care units are vulnerable to outbreaks and sporadic incidents of healthcare-associated infections (HAIs). The incidence and outcome of these infections are determined by the degree of immaturity of the neonatal immune system, invasive procedures involved, the aetiological agent and its antimicrobial susceptibility pattern and, above all, infection control policies practised by the unit. It is important to raise awareness of infection control practices in resource-limited settings, since overdependence upon antimicrobial agents and co-existing lack of awareness of infection control is encouraging the emergence of multi-drug-resistant nosocomial pathogens. We reviewed 125 articles regarding HAIs from both advanced and resource-limited neonatal units in order to study risk factors, aetiological agents, antimicrobial susceptibility patterns and reported successes in infection control interventions. The articles include surveillance studies, outbreaks and sporadic incidents. Gram-positive cocci, viruses and fungi predominate in reports from the advanced units, while Gram-negative enteric rods, non-fermenters and fungi are commonly reported from resource-limited settings. Antimicrobial susceptibility patterns from surveillance studies determined the empirical therapy used in each neonatal unit. Most outbreaks, irrespective of the technical facilities available, were traced to specific lack of infection control practices. We discuss infection control interventions, with special emphasis on their applicability in resource-limited settings. Cost-effective measures for implementing these interventions, with particular reference to the recognition of the role of the microbiologist, the infection control team and antibiotic policies are presented.

Nosocomial respiratory syncytial virus infection: Impact of prospective surveillance and targeted infection control

BACKGROUND

Nosocomially acquired respiratory syncytial virus (RSV) infections cause serious problems in hospitalized patients. An increased effort should be made to describe the problems connected with such infections in pediatric hospitals, with the aim of reducing the occurrence of nosocomial RSV infections (NI).

METHODS

A specialized database was introduced for surveillance and a multifaceted barrier concept based on the CDC recommendations was developed for the control of NI in a university children's hospital in Germany.

RESULTS

Between 1999 and 2002 (November 1-April 30), 283 RSV infections (general population) were prospectively documented. Thirty-nine cases (13.8%) were nosocomial infections (NI) with an incidence density (ID) of 0.99/1000 patient days; 48.7% of all NI were found in prematurely born infants. Following the introduction of a surveillance and prevention policy, a 9-fold decrease of the ID (1.67 vs. 0.18/1000 patient-days) was found when comparing the first and the last season. Intensive care treatment was required in 18% of all documented RSV-infections, in 48.7% of all NI cases and in 43.5% of all RSV-infected prematurely born infants. Overall RSV-related mortality was 0.71%.

CONCLUSIONS

Early diagnosis, a strict cohorting and contact isolation policy, and prospective surveillance contribute to the reduction of nosocomial RSV infection.

Health care-associated infections in the neonatal intensive care unit

Neonates represent a unique and highly vulnerable patient population. Advances in medical technology that have occurred over the last few decades have improved the survival and quality of life for neonates, particularly those infants born with extreme prematurity or with congenital defects. Although immunologic immaturity and altered cutaneous barriers play some role in the vulnerability of neonates to nosocomial infections, clearly, therapeutic interventions that have proven to be lifesaving for these fragile infants also appear to be associated with the majority of infectious complications resulting in neonatal morbidity and mortality. Rates of infections in neonatal intensive care units (NICUs) have varied from 6% to 40% of neonatal patients, with the highest rates in those facilities having larger proportions of very low-birth-weight infants (birthweight < or =1000 grams) or neonates requiring surgery. Efforts to protect the vulnerable NICU infants include the following: (1) optimal infection control practices, especially good hand hygiene and good nursery design; (2) prudent use of invasive interventions with particular attention to early removal of invasive devices after they are no longer essential; and (3) judicious use of antimicrobial agents, with an emphasis on targeted (narrow spectrum) rather than broad-spectrum antibiotics and appropriate indications (proven or suspected bacterial infections).

Development, implementation, and evaluation of a community- and hospital-based respiratory syncytial virus prophylaxis program

PURPOSE

To implement and deliver a respiratory syncytial virus prophylaxis (RSVP) program in response to the Canadian Pediatric Society recommendations.

METHODS

A novel program was designed to provide inpatient RSVP for at-risk infants cared for in 1 tertiary care newborn intensive care unit (NICU). This inpatient program was part of a coordinated approach to RSVP, designed and implemented by 3 hospitals. An RSVP program logic model was created and used by a multidisciplinary team to evaluate the in-house program and identify areas of program activity requiring improvement.

RESULTS

Following the 2000 to 2001 RSV season, a compliance and outcomes audit was performed in the tertiary center; 193 infants were enrolled in the RSVP program and 162 infants had received RSVP in the NICU [Mean = 1.64 doses]. Telephone follow-up with the parents of discharged infants identified that 159 infants (98%) had successfully completed their full course of RSVP. Using the RSVP program logic model, 5 areas for program improvement were identified including infant recruitment, patient transfer/discharge processes, product procurement, preparation/distribution/administration of doses, and healthcare team communication.

CONCLUSIONS

Interdisciplinary collaboration is an important factor in the success of the RSVP program and has supported a consistent model of care for the delivery of RSVP. The program logic model provided a useful structure to systematically review the RSVP program in this organization.

RSV outbreak in a paediatric intensive care unit

The Royal Liverpool Children's Hospital-Alder Hey paediatric intensive care unit (PICU) usually has a low rate of nosocomial respiratory syncytial virus (RSV) infection. We report and analyse a major outbreak of nosocomial (acquired) RSV infection on the PICU during a RSV season. All children admitted to the PICU were studied during the six-month winter period 1 October 2002 to 31 March 2002. Nasopharyngeal aspirates were tested using an in vitro enzyme-linked immunoassay (ELISA) membrane test for RSV antigen. PICU-acquired RSV infection was considered to have occurred when a child admitted to the PICU was RSV negative, or from whom no samples were taken as they did not exhibit signs of bronchiolitis, but was RSV positive five or more days after the admission. Fifty-four patients tested RSV positive using the ELISA on the PICU. All the patients were ventilated. Thirty-nine children were RSV positive using the ELISA on admission to the PICU ('imported' cases) and 15 became RSV positive whilst on the PICU ('acquired' cases). The source of the acquired RSV infection accounting for the first peak/outbreak in nosocomial cases were RSV-positive children in isolation cubicles. Acquired cases of RSV infection subsided with reinforcement of traditional methods of barrier precautions. The source of the second peak in nosocomial cases were persistent shedders of RSV. Seventy-three percent (11/15) of the acquired RSV cases had one or more of the following co-morbidities: congenital heart disease, chronic lung disease, airways abnormalities or immunosuppression. Droplet precautions (strict handwashing, use of gloves if handling body fluids, single-use aprons, education) rather than the physical barrier of the cubicle itself played a more important role in curtailing nosocomial spread. Persistent shedders of RSV are an important potential source of nosocomial RSV infection within a PICU. Patients with co-morbidities are at increased risk of nosocomial RSV infection.

Use of palivizumab to control an outbreak of syncytial respiratory virus in a neonatal intensive care unit

To evaluate the safety and effectiveness of a humanized respiratory syncytial virus (RSV) monoclonal antibody (palivizumab) to control an outbreak of RSV in a neonatal intensive care unit (NICU), we retrospectively analysed two RSV outbreaks. Between 11 November 1998 and 18 March 1999, two separate RSV outbreaks occurred in a large (26 beds) NICU. All procedures for preventing nosocomial spread of RSV (including the use of palivizumab in the second outbreak) were retrospectively analysed. The cumulative incidence (CI), secondary attack rate (SAR) and risk ratio of infection were determined before and after the use of palivizumab for all patients and for those with gestational age below and above 32 weeks in the NICU during the second outbreak. Standard infection control measures were effective in the first outbreak (three cases). In the second outbreak, after three index cases, five additional infants were newly RSV-infected within one month. Three infants had RSV pneumonia and required mechanical ventilation; one infant died. Standard infection control procedures were initiated from the beginning of this outbreak. Palivizumab was given to all infants in the NICU after the fifth case was identified. CI was 2.4% in the first 15 days and 10.5% in the second, and SAR was 2.9 per thousand in the first 15 days and 14.1 per thousand in the second, both dropping to zero after the administration of palivizumab. The risk ratio of infection was 4.65 times higher in infants under 32 weeks gestational age. After the use of palivizumab, there were no additional identified cases. In addition to careful infection control procedures, the use of palivizumab might have contributed to arresting the outbreak of RSV infection in the NICU, suggesting that it could be an additional resource in the control of severe nosocomial RSV outbreaks.

Microarray profiling of antiviral antibodies for the development of diagnostics, vaccines, and therapeutics

Multiplex analysis of antiviral antibody (Ab) responses provides a potentially powerful strategy for viral diagnosis, prognostication, and development of vaccines and prophylactic Abs. In the coming years, advancements in proteomic technologies will provide even more robust methods to characterize antiviral Ab responses. Biomedical researchers will be faced with the exciting challenge of identifying antiviral Ab specificities that correlate with improved outcomes and efficacious interventions, and translating the findings into more effective diagnostics, prophylactics, and therapeutics.

Nosocomial respiratory syncytial virus infection in neonatal units in the United Kingdom

Nosocomial Respiratory Syncytial Virus infections are frequently reported and tend to be more severe, because of comorbidity, such reports, however, are frequently from a single centre. The incidence and outcomes of nosocomial Respiratory Syncytial Virus infection in UK neonatal units over a five year period were estimated by interrogating the Capse Health Care Knowledge Systems database, which contains anonymised details of 55% of UK hospital admissions. A total of 79,642 admissions commenced on the infants' date of birth and contained an ICD-10 code for low birth weight or immaturity. Thirty-seven of the 79,642 admissions also contained a Respiratory Syncytial Virus code. Two (5.4%) with Respiratory Syncytial Virus and 2,736 (3.4%) without Respiratory Syncytial Virus died. Survivors with Respiratory Syncytial Virus codes experienced significantly increased length of stay. In the extreme immaturity sub-group the length of stay was 117.5 days with Respiratory Syncytial Virus and 51.3 days without Respiratory Syncytial Virus (p = 0.0002). In the low birth weight or other preterm sub-group the length of stay with Respiratory Syncytial Virus was 69.2 and without Respiratory Syncytial Virus 14.7 days (p < 0.0001). The observed low rate for nosocomial Respiratory Syncytial Virus (0.46/1000 admissions) should be regarded as a minimum. The increased length of stay in infants with Respiratory Syncytial Virus infection emphasises that units should have guidelines to prevent and deal with Respiratory Syncytial Virus outbreaks.

RSV molecular characterization and specific antibody response in young children with acute lower respiratory infection

The presence of respiratory syncytial virus (RSV) in nasopharyngeal aspirates (NPA) were studied in 254 hospitalized Argentinean children with acute lower respiratory infection tract (ALRI). The specific humoral immune response and partial sequences of the G protein gene were studied in a subset of 22 children with RSV confirmed infection. The RSV IgM detection and the RSV IgG titration were made by immunofluorescence assay (IFA) in pairs of sera. The partial RSV G gene sequences were obtained by an RT-PCR amplification directly from de NPAs. RSV was present in 44.5% of the children. The RSV IgM was detected in 22.7 and 68.8% of the first and second sera, respectively. The IgG geometric mean titers of the acute and convalescent sera were 8 and 589. The RSV IgG titration was able to define 86.4% of the RSV confirmed cases. The percentage of coincidence between RSV IgM detection in the second sera and diagnosis by RSV IgG titration was 72.7% and no significant differences were observed. The nucleotide sequence of one group A and three group B viruses were identified. The first one was related with circulating viruses in Madrid, Montevideo and Mozambique during 1992, 1989 and 1999, respectively. The three sequences identified as group B viruses were closely related with circulating viruses in 1998 from South Africa and Canada during 1999 and 2000. The data obtained in our study provide the first approach at the molecular level (nucleotide) of the RSV circulating strains in Argentina and the lack of genotype patterns previously determined make necessary a continuous molecular surveillance in order to contribute to the understanding of the behavior of this virus in our community.

Hospital-acquired viral pathogens in the neonatal intensive care unit

Hospital-acquired infections caused by viruses are a cause of considerable morbidity and occasional mortality in critically ill neonates. The intensive care environment allows for efficient spread of viral pathogens, and secondary cases among both patients and healthcare workers are frequently observed. We review the common viral causes of hospital-acquired infections in neonates, including rotavirus, respiratory syncytial virus, and others, discuss epidemiology and clinical syndromes, and summarize recommendations for control in outbreak situations. Chemoprophylaxis, isolation procedures, and care of affected staff are also addressed.

Nosocomial pneumonia in pediatric patients: practical problems and rational solutions

Nosocomial pneumonia is a common hospital-acquired infection in children, and is often fatal. Risk factors for nosocomial pneumonia include admission to an intensive care unit, intubation, burns, surgery, and underlying chronic illness. Viruses, predominantly respiratory syncytial virus (RSV), are the most common cause of pediatric nosocomial respiratory tract infections. Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) are the predominant bacterial pathogens, and are associated with a high mortality rate. Staphylococcus aureus and Staphylococcus epidermidis are the most common Gram-positive bacteria causing nosocomial pneumonia; infections with these organisms have a better outcome than those with Gram-negative organisms. An increasing problem is the emergence of multiresistant Gram-positive and Gram-negative nosocomial pathogens. Distinguishing nosocomial pneumonia from other pulmonary processes may be difficult; diagnosis is based on clinical signs, radiological findings, and microbiological results. Recommended empiric therapy should consider factors such as the time of onset of illness, severity of disease, and specific risk factors for nosocomial pneumonia, including use of mechanical ventilation, underlying disease, or recent use of antibacterials. The resident local hospital flora should be considered when selecting therapy for nosocomial pneumonia. Early initiation of appropriate empiric therapy reduces morbidity and mortality. For empiric treatment of bacterial nosocomial pneumonia, an intravenous antibacterial regimen that includes coverage of Gram-negative bacilli and Gram-positive organisms should be used. A carbapenem or ureidopenicillin derivative (piperacillin) plus a beta-lactamase inhibitor should be used where extended spectrum beta-lactamase-producing Enterobacteriaceae are endemic. Therapy should be modified when a specific pathogen and its antimicrobial susceptibility are identified. Effective prevention of nosocomial pneumonia requires infection control measures that affect the environment, personnel, and patients. Of these, hand hygiene, appropriate infection control policies, and judicious use of antibacterials are essential.

Respiratory syncytial virus infections in children and adults

Respiratory syncytial virus is the leading cause of hospital admission for lower respiratory tract infection in young children and appears to be responsible for a significant burden of disease in adults, particularly the elderly and the immunocompromised. In this review, we describe the epidemiology, diagnosis and clinical manifestations of infection attributed to this virus. We also consider current therapeutic and prophylactic options and appraise strategies for vaccination that are in clinical trials.

Prevention of nosocomial infections in the neonatal intensive care unit

Nosocomial infections are responsible for significant morbidity and late mortality among neonatal intensive care unit patients. The number of neonatal patients at risk for acquiring nosocomial infections is increasing because of the improved survival of very low birthweight infants and their need for invasive monitoring and supportive care. Effective strategies to prevent nosocomial infection must include continuous monitoring and surveillance of infection rates and distribution of pathogens; strategic nursery design and staffing; emphasis on handwashing compliance; minimizing central venous catheter use and contamination, and prudent use of antimicrobial agents. Educational programs and feedback to nursery personnel improve compliance with infection control programs.

Bronchiolitis: update 2001

In this review, reports from last year on the following topics are summarized: (1) reviews of bronchiolitis in infants; respiratory syncytial virus (RSV)-associated illness, including possible viral mechanisms of alteration of airway function and results of an epidemiologic study of bronchiolitis-associated mortality. Studies evaluating (2) the use of serum eosinophilic cationic protein as a marker for development of subsequent persistent wheezing infants; (3) parental bronchial responsiveness as an indicator of genetic susceptibility to acute bronchiolitis; (4) prophylactic use of monoclonal antibody (Palivizumab) to control an outbreak of RSV in a hospital nursery; (5) a controlled clinical trial of ribaviron in acutely ill children; (6) reports of new associations with bronchiolitis obliterans organizing pneumonia (BOOP); (7) case reports of use of methotrexate as an alternate to corticosteroids in treatment of BOOP; (8) a newly described entity, eosinophilic bronchiolitis.

Immunoprophylaxis of respiratory syncytial virus: global experience

Respiratory syncytial virus (RSV) infects nearly all children by age 2 years, and it causes considerable illness and death in certain high-risk pediatric populations. Historically, treatment for RSV has been symptomatic, and developing a safe and effective vaccine has been a challenge. Therefore, research efforts have turned to passive immunization as the best option to control RSV. Palivizumab, a genetically engineered humanized monoclonal antibody, has been shown to reduce RSV-related hospitalizations significantly, with few adverse effects. It was approved for use in high-risk children in the USA in 1998 and in Europe in 1999; it is now approved for use in more than 45 countries. The efficacy and safety of palivizumab continue to be supported by both clinical trial and outcomes data.