Screening for respiratory syncytial virus and assignment to a cohort at admission to reduce nosocomial transmission

Pragmatic Recommendations for Infection Prevention and Control Practices for Healthcare Facilities in Low- and Middle-Income Countries during the COVID-19 Pandemic

Infection prevention and control (IPC) strategies are key in preventing nosocomial transmission of COVID-19. Several commonly used IPC practices are resource-intensive and may be challenging to implement in resource-constrained settings. An international group of healthcare professionals from or with experience in low- and middle-income countries (LMICs) searched the literature for relevant evidence. We report on a set of pragmatic recommendations for hospital-based IPC practices in resource-constrained settings of LMICs. For cases of confirmed or suspected COVID-19, we suggest that patients be placed in a single isolation room, whenever possible. When single isolation rooms are unavailable or limited, we recommend cohorting patients with COVID-19 on dedicated wards or in dedicated hospitals. We also recommend that cases of suspected COVID-19 be cohorted separately from those with confirmed disease, whenever possible, to minimize the risk of patient-to-patient transmission in settings where confirmatory testing may be limited. We suggest that healthcare workers be designated to care exclusively for patients with COVID-19, whenever possible, as another approach to minimize nosocomial spread. This approach may also be beneficial in conserving limited supplies of reusable personal protective equipment (PPE). We recommend that visitors be restricted for patients with COVID-19. In settings where family members or visitors are necessary for caregiving, we recommend that the appropriate PPE be used by visitors. We also recommend that education regarding hand hygiene and donning/doffing procedures for PPE be provided. Last, we suggest that all visitors be screened for symptoms before visitation and that visitor logs be maintained.

Nosocomial Respiratory Viral Infection in the Neonatal Intensive Care Unit

Infections caused by respiratory viruses in neonates during their stay in the neonatal intensive care unit (NICU) are more frequent than generally suspected. Respiratory syncytial virus (RSV), a highly contagious pathogen, is the most common etiologic agent, and it carries a high risk of nosocomial spread. During the RSV season, overcrowding of the NICU, shortage of staff, and unrestricted visitors are factors predisposing outbreaks. Since signs and symptoms of RSV infections are no specific, a high index of suspicion is essential to prevent or limit epidemics. The etiologic agent should be confirmed and polymerase chain reaction (PCR) is the gold-standard test. Shedding of the virus by infected preterm infants is prolonged and RSV lasts for several hours on countertops and other surfaces. The first case should be isolated and strict cohorting must be instituted. Compliance with hand washing must be warranted. Wearing gowns and gloves may help. The severity of nosocomial RSV infections tends to be higher than that of those community acquired. There is no uniform recommendation to start palivizumab during hospital stay of premature and high-risk infants. The use of this monoclonal antibody to stop or limit the spread of outbreaks is controversial. It is recommended by some professional organizations and not by others but its use during large outbreaks in infants at risk who share the room with infected neonates is not uncommon. KEY POINTS: · During peak community epidemic, NICU outbreaks of RSV infections are not uncommon.. · High index of suspicion is essential as initial signs are nonspecific in preterm neonates.. · Isolation and cohorting, strict hand washing, gowns, gloves, and eventually palivizumab are main tools for management..

Room Sharing in Hospitalized Children With Bronchiolitis and the Occurrence of Hospital-Acquired Infections: A Prospective Cohort Study

OBJECTIVES

To determine the prevalence and severity of hospital-acquired infections (HAIs) in children hospitalized for bronchiolitis when patients share a room, irrespective of the causative virus.

METHODS

A prospective cohort study during 4 winter seasons (2012-2016) was conducted in a Dutch general pediatric ward including otherwise healthy children <2 years of age hospitalized for bronchiolitis. Patients shared a 1-to-4-bed hospital room irrespective of virological diagnosis. The main outcome measures were HAIs assessed through multiplex polymerase chain reaction and disease severity.

RESULTS

HAIs occurred in 28 of 218 included patients (12.8%), most frequently with rhinovirus (17 of 28; 60.7%). In 3 (10.7%) of 28 HAIs, the same virus was identified in roommates. Only 1 patient became cross-infected with respiratory syncytial virus, although this patient never shared a room with a patient infected with respiratory syncytial virus. HAI was not associated with more severe disease. The median length of hospitalization was 3.5 days (interquartile range [IQR] 1-6) compared with 3 days (IQR 2-6; P = .86); the number of PICU admissions was 0% versus 5.3% (P = .21); the median days of oxygen supplementation was 2.5 (IQR 1-4) versus 2 (IQR 1-4; P = .58); the median days of tube feeding was 2 (IQR 0-5) versus 2 (interquartile range: 0-5; P = .77); and the readmission rate was 0% versus 5.8% (P = .19) in patients with and without HAI, respectively.

CONCLUSIONS

HAIs among patients with bronchiolitis are common but not associated with more severe disease. Room sharing with appropriate hygiene does not play a relevant role in the transmission of viruses between patients with bronchiolitis, regardless of the viruses involved. On the basis of these findings, we suggest that room sharing of patients with bronchiolitis is safe.

Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies

In the USA and other western nations, respiratory syncytial virus is one of the most commonly encountered respiratory viruses among patients who have been diagnosed with a hematologic malignancy or who have undergone a stem cell transplant. Multiple studies have been performed to evaluate the complications associated with respiratory syncytial virus infections. Other studies have evaluated therapeutic agents and strategies in which these agents can be used. There have also been numerous reports of outbreaks in bone marrow transplant units and oncology wards, where infection control measures have been invaluable in controlling the spread of disease. However, despite these novel approaches, respiratory syncytial virus continues to be potentially fatal in immunocompromised populations. In this review, we discuss the incidence of respiratory syncytial viral infections, risk factors associated with progression from upper respiratory tract infection to lower respiratory tract infection, other complications and outcomes (including mortality), management strategies, and prevention strategies in patients with a hematologic malignancy and in hematopoietic cell transplant recipients.

Rapid and simple molecular tests for the detection of respiratory syncytial virus: a review

INTRODUCTION

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infections. The clinical manifestations of RSV are indistinguishable from other etiologies of acute respiratory infection. Therefore, accurate and timely laboratory testing is needed to impact clinical management. There are now multiple rapid, low-complexity, commercially available assays for RSV. These tests present significant performance advantages compared to older antigen detection tests. Accurate and rapid diagnosis of RSV has the potential for enabling timely cessation of unnecessary antibiotics and implementation of good infection control practices. Furthermore, a recently approved RSV diagnostic assay can reduce the test turnaround time to 13 min or less. Areas covered: The authors aim to review the importance of rapid and accurate testing for RSV and will describe the available molecular RSV diagnostic assays approved for use at the point-of-care. Expert commentary: Further independent evaluations are needed to confirm that the accuracy of the low-complexity assays is indeed similar to reverse transcriptase polymerase chain reaction across the age spectrum, and in immunosuppressed hosts. In the future, the challenge will be to achieve a balance between increasingly sophisticated multiplex diagnostic platforms and tests that are sufficiently simple to be used at the point-of-care.

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.

Diagnostic Accuracy of Rapid Antigen Detection Tests for Respiratory Syncytial Virus Infection: Systematic Review and Meta-analysis

Respiratory syncytial virus (RSV) rapid antigen detection tests (RADT) are extensively used in clinical laboratories. We performed a systematic review and meta-analysis to evaluate the accuracy of RADTs for diagnosis of RSV infection and to determine factors associated with accuracy estimates. We searched EMBASE and PubMed for diagnostic-accuracy studies of commercialized RSV RADTs. Studies reporting sensitivity and specificity data compared to a reference standard (reverse transcriptase PCR [RT-PCR], immunofluorescence, or viral culture) were considered. Two reviewers independently extracted data on study characteristics, diagnostic-accuracy estimates, and study quality. Accuracy estimates were pooled using bivariate random-effects regression models. Heterogeneity was investigated with prespecified subgroup analyses. Seventy-one articles met inclusion criteria. Overall, RSV RADT pooled sensitivity and specificity were 80% (95% confidence interval [CI], 76% to 83%) and 97% (95% CI, 96% to 98%), respectively. Positive- and negative-likelihood ratios were 25.5 (95% CI, 18.3 to 35.5) and 0.21 (95% CI, 0.18 to 0.24), respectively. Sensitivity was higher in children (81% [95% CI, 78%, 84%]) than in adults (29% [95% CI, 11% to 48%]). Because of this disparity, further subgroup analyses were restricted to pediatric data (63 studies). Test sensitivity was poorest using RT-PCR as a reference standard and highest using immunofluorescence (74% versus 88%; P < 0.001). Industry-sponsored studies reported significantly higher sensitivity (87% versus 78%; P = 0.01). Our results suggest that the poor sensitivity of RSV RADTs in adults may preclude their use in this population. Furthermore, industry-sponsored studies and those that did not use RT-PCR as a reference standard likely overestimated test sensitivity.

Bronchiolitis: Recommendations for diagnosis, monitoring and management of children one to 24 months of age

Bronchiolitis is the most common reason for admission to hospital in the first year of life. There is tremendous variation in the clinical management of this condition across Canada and around the world, including significant use of unnecessary tests and ineffective therapies. This statement pertains to generally healthy children ≤2 years of age with bronchiolitis. The diagnosis of bronchiolitis is based primarily on the history of illness and physical examination findings. Laboratory investigations are generally unhelpful. Bronchiolitis is a self-limiting disease, usually managed with supportive care at home. Groups at high risk for severe disease are described and guidelines for admission to hospital are presented. Evidence for the efficacy of various therapies is discussed and recommendations are made for management. Monitoring requirements and discharge readiness from hospital are also discussed.

Co-infections in children hospitalised for bronchiolitis: role of roomsharing

BACKGROUND

Bronchiolitis is a major cause for hospitalisation in young children during the winter season, with respiratory syncytial virus (RSV) as the main causative virus. Apart from standard hygiene measures, cohorting of RSV-infected patients separately from RSV-negative patients is frequently applied to prevent cross-infection, although evidence to support this practice is lacking. The objective is to evaluate the risk of room sharing between RSV-positive and RSV-negative patients.

METHODS

We performed a prospective observational cohort study in children < 2 years hospitalised with acute bronchiolitis. During the first day of admission, patients shared one room, pending results of virological diagnosis (PCR). When diagnostic results were available, RSV-positive and RSV-negative patients were separated. Standard hygienic measures (gowns, gloves, masks, hand washing) were used in all patients.

RESULTS

We included 48 patients (83% RSV-positive). Co-infection was found in nine patients at admission, and two during hospitalisation (23%). The two patients with acquired co-infection had been nursed in a single room during the entire admission. None of 37 patients sharing a room with other bronchiolitis patients (20 with patients with a different virus) were co-infected during admission. Disease severity in co-infection was not worse than in mono-infection.

CONCLUSION

One in five patients with bronchiolitis was co-infected, but co-infection acquired during admission was rare and was not associated with more severe disease. Room sharing between RSV-positive and RSV-negative patients (on the first day of admission) did not influence the risk of co-infection, suggesting that cohorting of RSV-infected patients separate from non-RSV-infected patients may not be indicated.

Comparison of the Biofire FilmArray RP, Genmark eSensor RVP, Luminex xTAG RVPv1, and Luminex xTAG RVP fast multiplex assays for detection of respiratory viruses

There are several U.S. FDA-cleared molecular respiratory virus panels available today, each with advantages and disadvantages. This study compares four multiplex panels, the BioFire Diagnostics FilmArray RP (respiratory panel), the GenMark Dx eSensor RVP (respiratory viral panel), the Luminex xTAG RVPv1, and the Luminex xTAG RVP fast. Three hundred specimens (200 retrospective and 100 consecutive) were tested using all four platforms to determine performance characteristics. The overall sensitivity and specificity, respectively, and 95% confidence interval (CI; in parentheses) for each panel were as follows: FilmArray RP, 84.5% (79.2, 88.6) and 100% (96.2, 100); eSensor RVP, 98.3% (95.5, 99.5) and 99.2% (95.4, 100); xTAG RVPv1, 92.7% (88.5, 95.4) and 99.8% (96.0, 100); and xTAG RVP fast, 84.4% (78.5, 88.9) and 99.9% (96.1, 100). The sensitivity of each assay fluctuated by viral target, with the greatest discrepancies noted for adenovirus and influenza virus B detection. Hands-on time and time to result were recorded and ease of use was assessed to generate a complete profile of each assay.

Respiratory syncytial virus disease: prevention and treatment

Respiratory syncytial virus (RSV) is one of the most clinically important viruses infecting young children, the elderly, and the immunocompromised. Over the past decade, the most significant advance in the prevention of RSV disease has been the development of high-titered antibody products. Infection control is the only other strategy to prevent RSV disease. A humanized monoclonal antibody directed against the fusion (F) protein palivizumab, (Synagis®, MedImmune, Inc., Gaithersburg, MD), is given routinely on a monthly basis to premature infants and young children less than 24 months of age with underlying medical problems including prematurity, chronic lung disease, or cardiac disease to prevent RSV disease and hospitalization. Other products utilizing polyclonal or monoclonal antibodies or antibody fragments against the F protein have been developed and some already tested in patient populations. The only licensed antiviral treatment available today is ribavirin, a guanosine analogue generally administered as a small particle aerosol to immunocompromised patients with lower respiratory tract disease due to RSV. This drug has also been utilized in oral and intravenous forms, again mainly in immunocompromised patients. Promising new antiviral agents under development by multiple pharmaceutical and biotechnology companies include small molecule fusion inhibitors, attachment inhibitors, inhibitors of RNA synthesis, and small interfering RNA particles (siRNA).

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a global threat. Antiviral drugs and vaccinations may be insufficient to prevent their spread.

OBJECTIVES

To review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

SEARCH STRATEGY

We searched The Cochrane Library, the Cochrane Central Register of Controlled Trials (CENTRAL 2010, Issue 3), which includes the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to October 2010), OLDMEDLINE (1950 to 1965), EMBASE (1990 to October 2010), CINAHL (1982 to October 2010), LILACS (2008 to October 2010), Indian MEDLARS (2008 to October 2010) and IMSEAR (2008 to October 2010).

SELECTION CRITERIA

In this update, two review authors independently applied the inclusion criteria to all identified and retrieved articles and extracted data. We scanned 3775 titles, excluded 3560 and retrieved full papers of 215 studies, to include 66 papers of 67 studies. We included physical interventions (screening at entry ports, isolation, quarantine, social distancing, barriers, personal protection, hand hygiene) to prevent respiratory virus transmission. We included randomised controlled trials (RCTs), cohorts, case-controls, before-after and time series studies.

DATA COLLECTION AND ANALYSIS

We used a standardised form to assess trial eligibility. We assessed RCTs by randomisation method, allocation generation, concealment, blinding and follow up. We assessed non-RCTs for potential confounders and classified them as low, medium and high risk of bias.

MAIN RESULTS

We included 67 studies including randomised controlled trials and observational studies with a mixed risk of bias. A total number of participants is not included as the total would be made up of a heterogenous set of observations (participant people, observations on participants and countries (object of some studies)). The risk of bias for five RCTs and most cluster-RCTs was high. Observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis. The highest quality cluster-RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Benefit from reduced transmission from children to household members is broadly supported also in other study designs where the potential for confounding is greater. Nine case-control studies suggested implementing transmission barriers, isolation and hygienic measures are effective at containing respiratory virus epidemics. Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. N95 respirators were non-inferior to simple surgical masks but more expensive, uncomfortable and irritating to skin. Adding virucidals or antiseptics to normal handwashing to decrease respiratory disease transmission remains uncertain. Global measures, such as screening at entry ports, led to a non-significant marginal delay in spread. There was limited evidence that social distancing was effective, especially if related to the risk of exposure.

AUTHORS' CONCLUSIONS

Simple and low-cost interventions would be useful for reducing transmission of epidemic respiratory viruses. Routine long-term implementation of some measures assessed might be difficult without the threat of an epidemic.

Respiratory syncytial virus prevention and therapy: past, present, and future

Respiratory syncytial virus (RSV) is the most common respiratory pathogen in infants and young children worldwide. More than 50 years after its discovery, and despite relentless attempts to identify pharmacological therapies to improve the clinical course and outcomes of this disease, the most effective therapy remains supportive care. Although the quest for a safe and effective vaccine remains unsuccessful, pediatricians practicing during the past decade have been able to protect at least the more vulnerable patients with safe and effective passive prophylaxis. This review summarizes the history, microbiology, epidemiology, pathophysiology, and clinical manifestations of this infection in order to provide the reader with the background information necessary to fully appreciate the many challenges presented by the clinical management of young children with bronchiolitis. The last part of this article attempts an evidence-based review of the pharmacologic strategies currently available and those being evaluated, intentionally omitting highly experimental approaches not yet tested in clinical trials and, therefore, not likely to become available in the foreseeable future.

Health care-acquired viral respiratory diseases

Health care-associated viral respiratory infections, common among hospitalized children, also occur among adults and institutionalized persons and result in increased patient morbidity, mortality, and health care costs. Approximately 20% of patients with healthcare-associated pneumonia have viral respiratory infections, with 70% of these infections caused by adenovirus, influenza virus, parainfluenza virus, and respiratory syncytial virus (RSV). These infections typically reflect the level of viral activity within the community. This article focuses on the epidemiology, transmission, and control of health care-associated RSV and influenza virus.

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.

Successful prevention of respiratory syncytial virus nosocomial transmission following an enhanced seasonal infection control program

Respiratory syncytial virus (RSV) infections can be serious in severely immunocompromised patients. Use of a targeted infection control program (TICP) has been shown to reduce RSV nosocomial transmission. We evaluated the impact of an enhanced seasonal infection control program (ESICP) vs standard TICP in a hematology-oncology ward. TICP was applied from 1999 to 2001 and ESICP applied from 2001 to 2003. ESICP consisted of strict isolation for all patients admitted on the ward during the RSV season. We prospectively evaluated the incidence, related morbidity and mortality of nosocomial RSV in both field interventions. A total of 40 hospitalized RSV infections were documented. The cumulative incidence of nosocomial RSV during TICP and ESICP was respectively of 42.8 and 3.9 cases/1000 admissions (relative risk = 0.09). ESICP needed to be implemented on 26 admitted patients on our ward to prevent one RSV nosocomial case. Furthermore, implementation of ESICP prevented four pneumonias and two deaths per RSV season. We conclude that ESICP is significantly more efficient than TICP to reduce the occurrence of nosocomial RSV infections and its related morbidity and mortality in patients with hematological malignancy and recipients of hematopoietic SCT.

Physical interventions to interrupt or reduce the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a world-wide threat. Antiviral drugs and vaccinations may be insufficient to prevent catastrophe.

OBJECTIVES

To systematically review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2); MEDLINE (1966 to May 2009); OLDMEDLINE (1950 to 1965); EMBASE (1990 to May 2009); and CINAHL (1982 to May 2009).

SELECTION CRITERIA

We scanned 2958 titles, excluded 2790 and retrieved the full papers of 168 trials, to include 59 papers of 60 studies. We included any physical interventions (isolation, quarantine, social distancing, barriers, personal protection and hygiene) to prevent transmission of respiratory viruses. We included the following study designs: randomised controlled trials (RCTs), cohorts, case controls, cross-over, before-after, and time series studies.

DATA COLLECTION AND ANALYSIS

We used a standardised form to assess trial eligibility. RCTs were assessed by: randomisation method; allocation generation; concealment; blinding; and follow up. Non-RCTs were assessed for the presence of potential confounders, and classified into low, medium, and high risks of bias.

MAIN RESULTS

The risk of bias for the four RCTs, and most cluster RCTs, was high. The observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis.The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. Six case-control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that N95 respirators were superior to simple surgical masks, but were more expensive, uncomfortable, and caused skin irritation. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. Global measures, such as screening at entry ports, were not properly evaluated. There was limited evidence that social distancing was effective especially if related to the risk of exposure.

AUTHORS' CONCLUSIONS

Many simple and probably low-cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long-term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.

Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review

OBJECTIVE

To review systematically the evidence of effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

DATA SOURCES

Cochrane Library, Medline, OldMedline, Embase, and CINAHL, without restrictions on language or publication. Data selection Studies of any intervention to prevent the transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection, and hygiene). A search of study designs included randomised trials, cohort, case-control, crossover, before and after, and time series studies. After scanning of the titles, abstracts and full text articles as a first filter, a standardised form was used to assess the eligibility of the remainder. Risk of bias of randomised studies was assessed for generation of the allocation sequence, allocation concealment, blinding, and follow-up. Non-randomised studies were assessed for the presence of potential confounders and classified as being at low, medium, or high risk of bias.

DATA SYNTHESIS

58 papers of 59 studies were included. The quality of the studies was poor for all four randomised controlled trials and most cluster randomised controlled trials; the observational studies were of mixed quality. Meta-analysis of six case-control studies suggested that physical measures are highly effective in preventing the spread of severe acute respiratory syndrome: handwashing more than 10 times daily (odds ratio 0.45, 95% confidence interval 0.36 to 0.57; number needed to treat=4, 95% confidence interval 3.65 to 5.52), wearing masks (0.32, 0.25 to 0.40; NNT=6, 4.54 to 8.03), wearing N95 masks (0.09, 0.03 to 0.30; NNT=3, 2.37 to 4.06), wearing gloves (0.43, 0.29 to 0.65; NNT=5, 4.15 to 15.41), wearing gowns (0.23, 0.14 to 0.37; NNT=5, 3.37 to 7.12), and handwashing, masks, gloves, and gowns combined (0.09, 0.02 to 0.35; NNT=3, 2.66 to 4.97). The combination was also effective in interrupting the spread of influenza within households. The highest quality cluster randomised trials suggested that spread of respiratory viruses can be prevented by hygienic measures in younger children and within households. Evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks was limited, but they caused skin irritation. The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remains uncertain. Global measures, such as screening at entry ports, were not properly evaluated. Evidence was limited for social distancing being effective, especially if related to risk of exposure-that is, the higher the risk the longer the distancing period.

CONCLUSION

Routine long term implementation of some of the measures to interrupt or reduce the spread of respiratory viruses might be difficult. However, many simple and low cost interventions reduce the transmission of epidemic respiratory viruses. More resources should be invested into studying which physical interventions are the most effective, flexible, and cost effective means of minimising the impact of acute respiratory tract infections.

Cochrane Review: Interventions for the interruption or reduction of the spread of respiratory viruses

Background

Viral epidemics or pandemics such as of influenza or severe acute respiratory syndrome (SARS) pose a significant threat. Antiviral drugs and vaccination may not be adequate to prevent catastrophe in such an event.

Objectives

To systematically review the evidence of effectiveness of interventions to interrupt or reduce the spread of respiratory viruses (excluding vaccines and antiviral drugs, which have been previously reviewed).

Search strategy

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, issue 4); MEDLINE (1966 to November 2006); OLDMEDLINE (1950 to 1965); EMBASE (1990 to November 2006); and CINAHL (1982 to November 2006).

Selection criteria

We scanned 2300 titles, excluded 2162 and retrieved the full papers of 138 trials, including 49 papers of 51 studies. The quality of three randomised controlled trials (RCTs) was poor; as were most cluster RCTs. The observational studies were of mixed quality. We were only able to meta‐analyse case‐control data. We searched for any interventions to prevent viral transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection and hygiene). Study design included RCTs, cohort studies, case‐control studies, cross‐over studies, before‐after, and time series studies.

Data collection and analysis

We scanned the titles, abstracts and full text articles using a standardised form to assess eligibility. RCTs were assessed according to randomisation method, allocation generation, concealment, blinding, and follow up. Non‐RCTs were assessed for the presence of potential confounders and classified as low, medium, and high risk of bias.

Main results

The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. The six case‐control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. The lack of proper evaluation of global measures such as screening at entry ports and social distancing prevent firm conclusions about these measures.

Authors' conclusions

Many simple and probably low‐cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long‐term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.

Plain language summary

Interventions to interrupt or reduce the spread of respiratory viruses

Although respiratory viruses usually only cause minor disease, they can cause epidemics. Approximately 10% to 15% of people worldwide contract influenza annually, with attack rates as high as 50% during major epidemics. Global pandemic viral infections have been devastating because of their wide spread. In 2003 the severe acute respiratory syndrome (SARS) epidemic affected ˜8,000 people, killed 780, and caused an enormous social and economic crisis. A new avian influenza pandemic caused by the H5N1 strain might be more catastrophic. Single measures (particularly the use of vaccines or antiviral drugs) may be insufficient to interrupt the spread.

We found 51 studies including randomised controlled trials (RCTs) and observational studies with a mixed risk of bias.

Respiratory virus spread might be prevented by hygienic measures around younger children. These might also reduce transmission from children to other household members. Implementing barriers to transmission, isolation, and hygienic measures may be effective at containing respiratory virus epidemics. There was limited evidence that (more uncomfortable and expensive) N95 masks were superior to simple ones. Adding virucidals or antiseptics to normal handwashing is of uncertain benefit. There is insufficient evaluation of global measures such as screening at entry ports and social distancing.

Diagnostic performance of a rapid antigen test for RSV in comparison with a 19-valent multiplex RT-PCR ELISA in children with acute respiratory tract infections

A rapid and reliable diagnosis of respiratory syncytial virus (RSV) infection in childhood is very important for clinical management. In this study we compared a rapid antigen test (enzyme immunoassay, EIA) for the detection of RSV with a reverse transcriptase polymerase chain reaction (RT-PCR) [19-valent multiplex RT-PCR enzyme-linked immunosorbent assay (ELISA)] to assess the diagnostic performance. Furthermore the diagnostic value of the EIA in terms of age and season relation was analyzed. A total of 400 nasopharyngeal or tracheal secretions from pediatric patients with clinical signs of lower respiratory tract infection were included. The specimen had to be taken in a standardized manner within 72 h after admission. Specimens were tested in parallel with the EIA and the multiplex RT-PCR ELISA. The RT-PCR technique was used as the target assay. The EIA reached a sensitivity of 58% and a specificity of 90% for all samples tested. For patients < [corrected] 1 year the post-test probability for a positive EIA was 91% during the RSV season; a negative test result decreased disease probability from 53 to 25%. For older patients a positive test raised disease probability from 23 to 45% during the RSV season. Negative test results did not markedly change disease probability.

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.

Interventions for the interruption or reduction of the spread of respiratory viruses

BACKGROUND

Viral epidemics or pandemics such as of influenza or severe acute respiratory syndrome (SARS) pose a significant threat. Antiviral drugs and vaccination may not be adequate to prevent catastrophe in such an event.

OBJECTIVES

To systematically review the evidence of effectiveness of interventions to interrupt or reduce the spread of respiratory viruses (excluding vaccines and antiviral drugs, which have been previously reviewed).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4); MEDLINE (1966 to November 2006); OLDMEDLINE (1950 to 1965); EMBASE (1990 to November 2006); and CINAHL (1982 to November 2006).

SELECTION CRITERIA

We scanned 2300 titles, excluded 2162 and retrieved the full papers of 138 trials, including 49 papers of 51 studies. The quality of three randomised controlled trials (RCTs) was poor; as were most cluster RCTs. The observational studies were of mixed quality. We were only able to meta-analyse case-control data. We searched for any interventions to prevent viral transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection and hygiene). Study design included RCTs, cohort studies, case-control studies, cross-over studies, before-after, and time series studies.

DATA COLLECTION AND ANALYSIS

We scanned the titles, abstracts and full text articles using a standardised form to assess eligibility. RCTs were assessed according to randomisation method, allocation generation, concealment, blinding, and follow up. Non-RCTs were assessed for the presence of potential confounders and classified as low, medium, and high risk of bias.

MAIN RESULTS

The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures around younger children. Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. The six case-control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. The lack of proper evaluation of global measures such as screening at entry ports and social distancing prevent firm conclusions about these measures.

AUTHORS' CONCLUSIONS

Many simple and probably low-cost interventions would be useful for reducing the transmission of epidemic respiratory viruses. Routine long-term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.

Diagnosis and management of bronchiolitis

Bronchiolitis is a disorder most commonly caused in infants by viral lower respiratory tract infection. It is the most common lower respiratory infection in this age group. It is characterized by acute inflammation, edema, and necrosis of epithelial cells lining small airways, increased mucus production, and bronchospasm. The American Academy of Pediatrics convened a committee composed of primary care physicians and specialists in the fields of pulmonology, infectious disease, emergency medicine, epidemiology, and medical informatics. The committee partnered with the Agency for Healthcare Research and Quality and the RTI International-University of North Carolina Evidence-Based Practice Center to develop a comprehensive review of the evidence-based literature related to the diagnosis, management, and prevention of bronchiolitis. The resulting evidence report and other sources of data were used to formulate clinical practice guideline recommendations. This guideline addresses the diagnosis of bronchiolitis as well as various therapeutic interventions including bronchodilators, corticosteroids, antiviral and antibacterial agents, hydration, chest physiotherapy, and oxygen. Recommendations are made for prevention of respiratory syncytial virus infection with palivizumab and the control of nosocomial spread of infection. Decisions were made on the basis of a systematic grading of the quality of evidence and strength of recommendation. The clinical practice guideline underwent comprehensive peer review before it was approved by the American Academy of Pediatrics. This clinical practice guideline is not intended as a sole source of guidance in the management of children with bronchiolitis. Rather, it is intended to assist clinicians in decision-making. It is not intended to replace clinical judgment or establish a protocol for the care of all children with this condition. These recommendations may not provide the only appropriate approach to the management of children with bronchiolitis.

Evaluation of the QuickLab RSV test, a new rapid lateral-flow immunoassay for detection of respiratory syncytial virus antigen

Rapid respiratory syncytial virus (RSV) diagnosis is vital to the prevention of nosocomial RSV infections. We evaluated a new rapid lateral-flow RSV immunoassay, the QuickLab RSV test, that requires use of only one reagent. We compared QuickLab to the Directigen RSV (DIR) assay, which requires six reagents, and direct fluorescent antibody (DFA) testing. DFA results were considered the "gold standard." For 133 nasopharyngeal aspirates tested, DFA results were 77 (57.8%) positive, 47 (35.3%) negative, and 9 (6.8%) indeterminate. The sensitivities, specificities, positive predictive values, and negative predictive values of QuickLab and DIR tests were 93.3% (70 of 75) and 80.8% (59 of 73), 95.6% (43 of 45) and 100.0% (46 of 46), 97.2% (70 of 72) and 100.0% (59 of 59), and 89.6% (43 of 48) and 76.7% (46 of 60), respectively. QuickLab was significantly (P = 0.02) more sensitive than DIR; the difference in specificities was not significant. DFA was more sensitive than DIR (P < 0.001) but not more sensitive than QuickLab (P = 0.45). The results of DIR testing were initially uninterpretable and required retesting with 15% of the specimens compared to 3% of QL results (P < 0.001). We conclude that the QuickLab RSV test has sensitivity similar to that of the DFA assay and better than that of the DIR assay. QuickLab testing is also simpler to perform and interpret than both DFA and DIR testing.

Bronchiolitis: assessment and evidence-based management

Viral bronchiolitis is the commonest cause of hospital admission in young infants. Respiratory syncytial virus is responsible for most cases of bronchiolitis. Secondary bacterial infection is rare and antibiotics are seldom necessary. Most children with bronchiolitis develop only mild illness and can be managed at home. Infants born prematurely, those with pre-existing cardiac or respiratory disease, and infants in the first three months of life are more likely to need hospital admission. On current evidence, nebulised adrenaline, inhaled and systemic corticosteroids, and inhaled bronchodilators do not have a role in the routine management of infants with bronchiolitis.

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.

Controversies in isolation and general infection control practices in pediatrics

Current controversies in pediatric isolation and infection control include correct application of standard precautions, importance of providing adequate staffing levels in intensive care units to prevent transmission of infectious agents, use of rapid diagnostic testing and best precautions to prevent transmission of respiratory syncytial virus, best methods to prevent transmission of multidrug-resistant organisms in acute care settings, and preventing transmission of infections to pregnant healthcare workers. Recommendations are evidence-based.

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

An outbreak of respiratory syncytial virus (RSV) infection affected seven premature infants in a special care baby unit during November and December 1999. Conventional infection control measures (cohorting infected babies, strict reinforcement of the use of gloves and aprons, emphasis on hand disinfection) failed to prevent spread. Palivizumab, a respiratory syncytial virus monoclonal antibody, was given to eight high-risk preterm infants. There were no further cases of RSV in the unit and none of the babies given palivizumab developed RSV. One baby who acquired RSV during the outbreak (and who was not given palivizumab) was subsequently admitted to hospital with another episode of RSV bronchiolitis. The role of palivizumab in the control of hospital outbreaks of RSV infection merits further investigation.

Diagnostic virology

Diagnostic virology has now entered the mainstream of medical practice. Multiple methods are used for the laboratory diagnosis of viral infections, including viral culture, antigen detection, nucleic acid detection, and serology. The role of culture is diminishing as new immunologic and molecular tests are developed that provide more rapid results and are able to detect a larger number of viruses. This review provides specific recommendations for the diagnostic approach to clinically important viral infections.

Nosocomial respiratory syncytial virus infections: the cost-effectiveness and cost-benefit of infection control

OBJECTIVE

To determine the cost-effectiveness and cost-benefit of an infection control program to reduce nosocomial respiratory syncytial virus (RSV) transmission in a large pediatric hospital.

DESIGN

RSV nosocomial infection (NI) was studied for 8 years, before and after intervention with a targeted infection control program. The cost-effectiveness of the intervention was calculated, and cost-benefit was estimated by a case-control comparison.

SETTING

Children's Hospital of Philadelphia, a 304-bed pediatric hospital.

PATIENTS

All inpatients with RSV infection, both community- and hospital-acquired.

INTERVENTION

Consisted of early recognition of patients with respiratory symptoms, confirmation of RSV infection by laboratory testing, establishing cohorts of patients and nursing staff, gown and glove barrier precautions, and monitoring and education of staff.

OUTCOME MEASURES

The incidence density of RSV NI before and after the intervention was calculated as the rate per 1000 patient days-at-risk for infection. Intervention costs included laboratory testing, isolation, and administration of the program. The cost of RSV NI was estimated by comparing hospital charges for 30 cases and matched uninfected controls.

RESULTS

A total of 148 patients acquired NI (88 before and 60 after the intervention). The Mantel-Haenszel stratified relative risk for NI in the period before the infection control program, compared with the postintervention period, was.61 (95% confidence interval:.53-.69). By applying the preintervention stratum-specific rates of infection to the days-at-risk in the postintervention period, an estimated 100 NIs would have been expected, which in comparison to the 60 NIs observed, yielded an estimated program effectiveness of 10 RSV NIs prevented per season. The total cost of the program per season was $15 627 or $1,563/NI prevented. In comparison, the mean cost to the hospital was $9,419/case of RSV NI, resulting in a cost-benefit ratio of 1:6.

CONCLUSIONS

A targeted infection control intervention was cost-effective in reducing the rate of RSV NI. For every dollar spent on the program, approximately $6 was saved.

Nosocomial respiratory syncytial virus infections in children's wards

During community outbreak, nosocomial infections caused by both groups (A and B) of respiratory syncytial virus (RSV) occur as the most common nosocomial infections at pediatric wards. RSV cross-infection is considered to have taken place when a child acquires an infection after being in the ward longer than 7 days, and its frequency at the ward could be calculated in several ways. That frequency ranges worldwide between 30% and 70% in neonatal units, and between 20% and 40% at pediatric wards. The infections are manifested as lower respiratory tract infections (LRTI) in 20-60% and 30-40% of cases, respectively. These infections could be early diagnosed by an RSV rapid detection method. In RSV-positive children who develop LRTI and belong to the category with a high risk of developing severe RSV disease, a specific therapy is recommended. The frequency of RSV nosocomial infections at children's wards could be considerably reduced (to only a few per cent) by providing education to hospital personnel in the etiology and transmission of respiratory viruses and by compliance with pediatric droplet precautions (cohort nursing, and gown and glove wearing/handwashing in any contact with infected children).

Control of an outbreak of respiratory syncytial virus infection in immunocompromised adults

Respiratory syncytial virus (RSV) is increasingly recognized as an important pathogen in immunocompromised adults, particularly those receiving bone marrow transplants, and, given the ease with which it spreads, represents a significant nosocomial problem. We describe an outbreak of RSV infection involving eight patients on a haematology/oncology ward which was controlled by early screening of patients and staff. Positive patients were cohort nursed on a separate ward and basic infection control measures including use of gowns and gloves were enforced. Children under age 12 were denied ward access. All patients with lower respiratory tract infection, and bone marrow transplant recipients with upper respiratory symptoms, were treated with nebulized ribavirin. There were no deaths. We conclude that awareness of the risk of RSV infection in immunocompromised patients coupled with rapid diagnosis and treatment, screening of symptomatic patients and staff, cohort nursing of cases and basic infection control procedures can prevent spread of RSV infection and reduce morbidity.

Reducing the rate of nosocomially transmitted respiratory syncytial virus

BACKGROUND

A large number (17) of nosocomial respiratory syncytial virus cases led to the development of control measures to prevent transmission of respiratory syncytial virus (RSV) within the Johns Hopkins Hospital's Children's Center.

METHODS

The control plan is based on a 2-stage process. In stage 1, the staff are notified that RSV is in the community, and information is distributed through a communication tree. Stage 2 requires that nasopharyngeal aspirates be obtained from all children <3 years of age who have respiratory symptoms. The aspirates are tested directly for RSV antigen and cultured for RSV. The children are placed on pediatric droplet precautions pending those results.

RESULTS

The proportion of nosocomial RSV cases dropped from 16.5% before the use of RSV control measures to 7.2% after the initiation of the control program. A case of RSV identified in the hospital was 2.6 times more likely to be nosocomially acquired before the intervention compared with after the intervention. Approximately 14 cases of RSV are prevented each year, which results in a savings of 56 hospital-days and more than $84,000 in direct hospital-related charges alone.

CONCLUSIONS

The nosocomial spread of RSV can be reduced by a specific and feasible control plan that includes early identification and rapid isolation of potential RSV cases.

-Prevention of respiratory syncytial virus infection-

Respiratory syncytial virus (RSV) is responsible for annual outbreaks of severe respiratory disease among infants. Its prevention has been considered for many years but the first vaccination trials resulted in diseases of increased severity. New vaccines are in progress with promising results, although their efficacy in the presence of maternal antibodies, and their tolerance in very young babies, remain to be demonstrated. Concerning passive immunization, intravenous anti-RSV immunoglobulins have been successfully tested in children at risk of severe bronchiolitis; however this prophylaxis is not applicable to healthy children. The use of local immunization with intranasal monoclonal antibodies is under study. While waiting for a safe and efficient immunization against RSV, prevention of nosocomial infections by cohorting and handwashing is recommended.

Cohorting of infants with respiratory syncytial virus

During two winter periods (1994-1995 and 1995-1996), nasopharyngeal aspirates were obtained from infants and young children with an acute respiratory illness, after initial assessment in an area with six cubicles which serves as an admissions unit. Aspirates were sent for rapid diagnostic testing. Respiratory syncytial virus (RSV) positive patients were cohorted into two six-bedded bays on the paediatric wards. Over the two successive winter periods studied, 347 RSV positive patients were assigned to the cohort. No nosocomial infections were identified during the first winter; in the second, two were identified. Cohorting at admission eased clinical management, with one area used for high-dependency care and cubicles being freed for children with other infectious diseases. Nosocomial infection was minimized.

Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: a Pediatric Investigators Collaborative Network on Infections in Canada Study

OBJECTIVE

To determine nosocomial transmission of respiratory syncytial virus (RSV) in Canadian pediatric hospitals, outcomes associated with nosocomial disease, and infection control practices.

DESIGN

A prospective cohort study in the 1992 to 1994 winter respiratory seasons.

SETTING

Nine Canadian pediatric university-affiliated hospitals.

PARTICIPANTS

Hospitalized children with symptoms of lower respiratory tract infection (at least one of cough, wheezing, dyspnea, tachypnea, and apnea) and RSV antigen identified in a nasopharyngeal aspirate.

RESULTS

Of 1516 children, 91 (6%) had nosocomial RSV (NRSV), defined as symptoms of lower respiratory tract infection and RSV antigen beginning >72 hours after admission. The nosocomial ratio (NRSV/[com-munity-acquired RSV {CARSV})] + NRSV) varied by site from 2.8% to 13%. The median length of stay attributable to RSV for community-acquired illness was 5 days, but 10 days for nosocomial illness. Four children with NRSV (4. 4%) died within 2 weeks of infection, compared with 6 (0.42%) with CARSV (relative risk = 10.4, 95% confidence interval: 3.0, 36.4). All sites isolated RSV-positive patients in single rooms or cohorted them. In a multivariate model, no particular isolation policy was associated with decreased nosocomial ratio, but gowning to enter the room was associated with increased risk of RSV transmission (incidence rate ratio 2.81; confidence interval: 1.65, 4.77).

CONCLUSIONS

RSV transmission risk in Canadian pediatric hospitals is generally low. Although use of barrier methods varies, all sites cohort or isolate RSV-positive patients in single rooms. Children with risk factors for severe disease who acquire infection nosocomially have prolonged stays and excess mortality.

Prevention and treatment recommendations for respiratory syncytial virus infection. Background and clinical experience 40 years after discovery

Though 40 years have passed since its discovery, respiratory syncytial virus (RSV), one of the most ubiquitous viruses known, continues to evade most of our efforts to prevent or treat the clinical disease it causes. Long recognised as the most common cause of lower respiratory tract infections in virtually all children in the first 2 years of life, it has been increasingly recognised as a cause of more serious disease in several 'high risk' populations. These populations include infants with cardiac or pulmonary disease and infants and adults with immunodeficiencies, particularly those undergoing bone marrow transplantation. Early attempts to immunise children with a simple formalin-inactivated vaccine led to severe disease in vaccinated children who subsequently were infected with RSV from the community. Other vaccine constructs have failed for a variety of reasons, although surface glycoprotein subunit vaccines may hold promise. For years, ribavirin, a synthetic nucleoside analogue administered by constant aerosol, has been felt by many to lead to more rapid improvement in clinical disease caused by RSV, but it is still unclear whether its benefits are truly significant. An intravenous immunoglobulin product prepared from donors screened for the presence of high titres of RSV neutralising antibody (known as RSVIG) appears to be well tolerated and relatively effective in protecting high-risk infants against serious RSV disease, although therapeutic use has proven less dramatic. At least one monoclonal antibody undergoing current testing may prove easier to use in similar immunoprophylactic use. Results on the use of corticosteroids as supportive therapy have not been conclusive. In short, RSV will continue to be a challenge for clinicians and researchers well into the next century.