Respiratory Syncytial Virus Transmission Research Articles

The impact of infection control upon hospital-acquired influenza and respiratory syncytial virus

Respiratory syncytial virus (RSV) and influenza are important pediatric community-acquired (CA) and hospital-acquired (HA) pathogens. The occurrence of pandemic (H1N1) 2009 influenza resulted in additional efforts to intensify infection control (IC) strategies. We detail the impact of IC strategies between 2003 and 2010 on influenza and RSV. We assessed the rates of CA infections per 100 admissions and HA infections per 1000 patient-days for both RSV and influenza at Children's Memorial Hospital during the winter seasons (September through May) 2003-2010. The season of 2009, however, was extended through June due to ongoing admissions as a result of pandemic (H1N1) 2009 influenza. IC strategies implemented in response to pandemic (H1N1) 2009 influenza are described. The transmission ratio (HA cases/CA cases) was determined and correlated with IC efforts. Substantial season- to-season variability exists for CA RSV and CA influenza rates. The rates of HA RSV and HA influenza and the transmission ratios for these viruses remained unchanged in 2009-10 in comparison to the prior year (at 0.02 and 0.01, respectively) despite implementation of multiple IC strategies. In contrast, since 2005 an inverse association was noted between hand hygiene compliance and the transmission ratio of both RSV and influenza, with Spearman correlation coefficients of -0.84 (p = 0.051) and -0.89 (p = 0.008), respectively. We observed that improvements in hand hygiene compliance correlated with less transmission of RSV and influenza in the hospital. The important role of hand hygiene in preventing transmission of RSV and influenza to hospitalized children should be emphasized.

Impact of respiratory syncytial virus: the nurse's perspective.

Respiratory syncytial virus (RSV) is a highly contagious virus, and is the major cause of lower respiratory tract infections in infants and toddlers worldwide.RSV infection poses serious health risks to young children during the first 2 years of life. Several infant populations have been classified as high risk, and additional risk factors are known to increase the likelihood of severe RSV infection. Treatment for active RSV infection is limited to the symptoms of infection rather than the underlying cause; therefore, it is critical to reduce the transmission of RSV. As nurses, we highlight the importance of educating healthcare professionals, both in the hospital and community settings, aswell as parents and other caregivers about the risks and outcomes associated with RSV infection, and necessarymeasures to decrease the risk of infection. We also highlight the importance of the successful identification of those children who are at high risk of RSV infection. RSV prophylaxis (RSVP) with palivizumab has been shown to improve clinical outcome in infants who are considered high risk compared with those who have not received RSVP. The failure of healthcare staff and primary caregivers to protect children against an RSV infection can have lasting detrimental effects on the health and lives of affected children and their families.

Impact of Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is a highly contagious virus, and is the major cause of lower respiratory tract infections in infants and toddlers worldwide.RSV infection poses serious health risks to young children during the first 2 years of life. Several infant populations have been classified as high risk, and additional risk factors are known to increase the likelihood of severe RSV infection. Treatment for active RSV infection is limited to the symptoms of infection rather than the underlying cause; therefore, it is critical to reduce the transmission of RSV. As nurses, we highlight the importance of educating healthcare professionals, both in the hospital and community settings, aswell as parents and other caregivers about the risks and outcomes associated with RSV infection, and necessarymeasures to decrease the risk of infection. We also highlight the importance of the successful identification of those children who are at high risk of RSV infection. RSV prophylaxis (RSVP) with palivizumab has been shown to improve clinical outcome in infants who are considered high risk compared with those who have not received RSVP. The failure of healthcare staff and primary caregivers to protect children against an RSV infection can have lasting detrimental effects on the health and lives of affected children and their families.

Rapid testing for respiratory syncytial virus in a paediatric emergency department: benefits for infection control and bed management

Respiratory syncytial virus (RSV) is responsible for annual winter outbreaks of respiratory tract infection among children in temperate climates, placing severe pressure on hospital beds. Cohorting of affected infants has been demonstrated to be an effective strategy in reducing nosocomial transmission of RSV, and may keep cubicles free for other patients who require them. Testing of symptomatic children for RSV is standard practice, but unfortunately traditional laboratory testing is not rapid enough to aid decision-making processes. Rapid point-of-care testing (POCT) in the emergency department has been suggested as an alternative. We performed a prospective study to quantify the amount of cubicle time saved by using POCT results to allow a targeted cohorting strategy. Over the four-month study period, the POCT allowed 183 children to be admitted directly to a designated cohort area, thus saving 568.5 cubicle-days for other patients. This is equivalent to five cubicles being left free for each day of the study period. This is the first time the benefits of using POCT have been quantified in this way. POCT for RSV is a safe, cost-effective and efficient way to improve bed management.

Transmission of respiratory syncytial virus at the paediatric intensive-care unit: a prospective study using real-time PCR

AbstractTransmission of respiratory syncytial virus (RSV) from children with lower respiratory tract infection (LRTI) at a paediatric intensive-care unit (PICU) was examined using a highly sensitive real-time PCR. Twenty-four children with RSV LRTI were admitted during the study period (total days of potential transmission: 239). Fortyeight RSV-negative patients were followed up for RSV acquisition every 5 days (total days of exposure: 683). No single RSV transmission was documented with this highly sensitive diagnostic method. Therefore, routine infection control measures of LRTI patients seem to be adequate to prevent RSV transmission at the PICU.

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.

Protecting healthcare workers from pandemic influenza: N95 or surgical masks?

The successful management of an influenza pandemic will be reliant on the expertise of healthcare workers at high risk for occupationally acquired influenza. Recommended infection control measures for healthcare workers include surgical masks to protect against droplet-spread respiratory transmissible infections and N95 masks to protect against aerosol-spread infections. A literature review was undertaken for evidence of superior protective value of N95 masks or surgical masks for healthcare workers against influenza and extraneous factors influencing conferred protection. Four scientific search engines using 12 search sequences identified 21 mask studies in healthcare settings for the prevention of transmission of respiratory syncytial virus, Bordetella pertussis, and severe acute respiratory syndrome. Each was critically assessed in accordance with Australian National Health Medical Research Council guidelines. An additional 25 laboratory-based publications were also reviewed. All studies reviewed used medium or lower level evidence study design. In the majority of studies, important confounders included the unrecognized impact of concurrent bundling of other infection control measures, mask compliance, contamination from improper doffing of masks, and ocular inoculation. Only three studies directly compared the protective value of surgical masks with N95 masks. The majority of laboratory studies identified both mask types as having a range of filtration efficiency, yet N95 masks afford superior protection against particles of a similar size to influenza. World Health Organization guidelines recommend surgical masks for all patient care with the exception of N95 masks for aerosol generating procedures. Because of the paucity of high-quality studies in the healthcare setting, the advocacy of mask types is not entirely evidence-based. Evidence from laboratory studies of potential airborne spread of influenza from shedding patients indicate that guidelines related to the current 1-meter respiratory zone may need to be extended to a larger respiratory zone and include protection from ocular inoculation.

Duration of shedding of respiratory syncytial virus in a community study of Kenyan children

BackgroundOur understanding of the transmission dynamics of respiratory syncytial virus (RSV) infection will be better informed with improved data on the patterns of shedding in cases not limited only to hospital admissions.MethodsIn a household study, children testing RSV positive by direct immunofluorescent antibody test (DFA) were enrolled. Nasal washings were scheduled right away, then every three days until day 14, every 7 days until day 28 and every 2 weeks until a maximum of 16 weeks, or until the first DFA negative RSV specimen. The relationship between host factors, illness severity and viral shedding was investigated using Cox regression methods.ResultsFrom 151 families a total of 193 children were enrolled with a median age of 21 months (range 1-164 months), 10% infants and 46% male. The rate of recovery from infection was 0.22/person/day (95% CI 0.19-0.25) equivalent to a mean duration of shedding of 4.5 days (95%CI 4.0-5.3), with a median duration of shedding of 4 days (IQR 2-6, range 1-14). Children with a history of RSV infection had a 40% increased rate of recovery i.e. shorter duration of viral shedding (hazard ratio 1.4, 95% CI 1.01-1.86). The rate of cessation of shedding did not differ significantly between males and females, by severity of infection or by age.ConclusionWe provide evidence of a relationship between the duration of shedding and history of infection, which may have a bearing on the relative role of primary versus re-infections in RSV transmission in the community.

Randomness in a mathematical model for the transmission of respiratory syncytial virus ( [formula omitted

In this paper we study the dynamics of the transmission of respiratory syncytial virus ( R S V ) in human populations using random differential equation systems. Since initial conditions and some parameters of a R S V mathematical model are subject to some degree of uncertainty, randomness on the model are introduced. In order to modeling these uncertainties some probability distributions functions are assumed for initial conditions and parameters. Monte Carlo method is applied to investigate the effect of parameters and initial conditions uncertainties on the dynamics behavior of the infected and recovered populations. In addition numerical predictions for the future dynamics of R S V transmission in the population from the Spanish region of Valencia are obtained using confidence intervals and expected mean values for the infected and recovered populations are also obtained.

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.

The relationship of meteorological conditions to the epidemic activity of respiratory syncytial virus

Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. We recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases, and reviewed similar reports from other areas varying in climate. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature. UVB radiation may inactivate the virus in the environment, or influence susceptibility to RSV by altering host resistance. Activity of RSV in the community is controlled by many factors, including climate and behaviour of the population. Accurate information on when to institute and withdraw prophylactic therapy against RSV will depend on local epidemiological data.

Nosocomial RSV infection control and outbreak management

The incidence of nosocomial respiratory syncytial virus (RSV) infection in different areas of the world is not well known. However, it is clear that RSV infection of hospitalized infants with congenital heart disease or following preterm birth is highly relevant. Nosocomial RSV infection in these high-risk group infants often follows a severe course of disease, even resulting in mortality. Transmission of RSV mainly occurs through direct contact, but not through inhalation. Consequently, prevention of nosocomial RSV infection should aim to prevent direct contact between non-infected infants and RSV-infected people. Evidence of the role of gowns, masks and gloves is discussed. The effect and safety of cohorting RSV-infected infants is reviewed. International guidelines with respect to RSV prevention and outbreak management are analysed.

Emerging drugs for respiratory syncytial virus infection

Although respiratory syncytial virus (RSV) was discovered > 40 years ago, treatment remains largely supportive. There are no safe and effective vaccines or specific treatments other than prophylaxis with passive antibody therapy (palivizumab). However, there are good reasons to think that the scene may soon change. As the pace of development of anti-viral drugs accelerates and optimism over vaccines increases, novel therapies are set to make a major impact in the management of this very common infection. The use and effect of such interventions are not easy to anticipate, but could ultimately include the interruption of RSV's transmission resulting in profound changes to the impact ozf RSV on human health.

Stochastic modeling of the transmission of respiratory syncytial virus ( RSV) in the region of Valencia, Spain

In this paper, we study the dynamics of the transmission of respiratory syncytial virus ( RSV) in the population using stochastic models. The stochastic models are developed introducing stochastic perturbations on the demographic parameter as well as on the transmission rate of the RSV. Numerical simulations of the deterministic and stochastic models are performed in order to understand the effect of fluctuating birth rate and transmission rate of the RSV on the population dynamics. The numerical solutions of stochastic models are calculated using Euler-Maruyama and Milstein schemes, and confidence intervals for stochastic solutions are given using Monte-Carlo method. Analysis of the numerical results reveals that perturbations on the transmission rate are more decisive in the dynamics of RSV than perturbations on demographic parameters. In addition, the stochastic models show the advantage of reproducing more effectively the noisy RSV hospitalization data. It is concluded that these stochastic models are a viable option to provide a realistic modeling of the RSV dynamics on the population.

Strategies for preventing respiratory syncytial virus

Prevention of respiratory syncytial virus (RSV) infection-crucial for decreasing the burden associated with this disease-is discussed. Predictable outbreaks of RSV occur annually throughout the U.S. During these outbreaks, RSV infection spreads readily among children through close contact with infected individuals or contact with contaminated surfaces or objects. RSV is the leading cause of infant hospitalization and is associated with life-changing and life-threatening complications. Prevention is important for reducing the associated morbidity and mortality. The American Academy of Pediatrics (AAP) has outlined ways to prevent RSV transmission. According to the AAP, frequent hand washing is the most important strategy for reducing the burden of RSV disease. Other methods for controlling nosocomial spread of RSV include the use of gloves, frequent glove changes, and isolating or cohorting patients. General prevention measures that can be undertaken by family members include smoking cessation, breastfeeding, and avoiding situations, whenever possible, where exposure to RSV cannot be controlled. Passive immunoprophylaxis with palivizumab, the only agent approved by the FDA, reduces hospitalization in high-risk children. Palivizumab is currently the only agent approved by the FDA for the prevention of RSV infections in high-risk children. Not every child is equally at risk for serious RSV disease, and immunoprophylaxis is indicated only for certain high-risk children. The AAP has issued specific guidelines for RSV immunoprophylaxis with palivizumab. Other therapies are emerging for the prevention of RSV, including a new, enhanced-potency, humanized RSV monoclonal antibody and several different types of vaccines. RSV causes an annual, predictable epidemic. Treatment remains exclusively supportive. Prevention remains the cornerstone of disease management. The AAP has issued guidelines to protect those at high risk.

Existence of periodic solutions in a model of respiratory syncytial virus RSV

In this paper we study the existence of a positive periodic solutions for nested models of respiratory syncytial virus RSV, by using a continuation theorem based on coincidence degree theory. Conditions for the existence of periodic solutions in the model are given. Numerical simulations related to the transmission of respiratory syncytial virus in Madrid and Rio Janeiro are included.

Non-standard numerical method for a mathematical model of RSV epidemiological transmission

Respiratory Syncytial Virus (RSV) has long been recognized as the single most important virus causing acute severe respiratory-tract infections with symptoms ranging from rhinitis to bronchitis in children who may require hospitalization. Outbreaks of RSV occur every year and all children become infected within the first two years of life, and that overloads hospital casualty services. The transmission dynamics of RSV are strongly seasonal. Epidemics occur each winter in temperate climates and often coincide with the seasonal rainfall in tropical climates. In this paper we develop a non-standard numerical scheme for a SIRS seasonal epidemiological model for RSV transmission. This non-standard numerical scheme preserves the positivity of the continuous model and is applied to approximate the solution using different sizes of step. Finally this method is compared with some well-known explicit methods and simulations with data from Gambia and Finland are carried out.

Temperature, Humidity, and Ultraviolet B Radiation Predict Community Respiratory Syncytial Virus Activity

To obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection, RSV activity was recorded year-round in 9 cities that differ markedly in geographic location and climate. Local weather conditions were correlated with weekly or monthly RSV cases. Similar reports from other areas varying in climate were also reviewed. Results demonstrated that for all sites combined, weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures more than 24-30 degrees C and at 2-6 degrees C. RSV activity also was greatest at 45-65% relative humidity. RSV activity was inversely related to ultraviolet B (UVB) radiance at 3 sites where this could be analyzed; the fourth site had minimal amounts of annual UVB radiance. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained cold throughout the year, RSV activity again became nearly continuous. These data led us to conclude that community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols; transmission of RSV in cooler climates is inversely related to temperature, possibly as a result of increased stability of the virus in secretions in the colder environment; and UVB radiation may inactivate the virus in the environment or influence susceptibility to RSV by altering host resistance.

Modeling the spread of seasonal epidemiological diseases: Theory and applications

In this paper we study the existence and uniqueness of periodic solutions of seasonal epidemiological disease, by using a continuation theorem based on coincidence degree theory. We obtain criteria for the existence, uniqueness and global asymptotic stability of the periodic solution of the system. Examples related to the transmission of respiratory syncytial virus are included.

Health Care Epidemiology Perspective on the October 2006 Recommendations of the Subcommittee on Diagnosis and Management of Bronchiolitis

The recent evidence-based clinical practice guideline “Diagnosis and Management of Bronchiolitis,”1 developed by the American Academy of Pediatrics Subcommittee on Diagnosis and Management of Bronchiolitis and published in the October 2006 issue of Pediatrics , is a welcome comprehensive and practical tool for assisting clinicians in managing bronchiolitis in young children. In this commentary we present the views of the Pediatric Special Interest Group (PSIG) of the Society for Healthcare Epidemiology of America on several aspects of the guideline related to the management of children who are hospitalized with bronchiolitis. Established in October 2006, the PSIG comprises pediatric infectious-disease physicians and infection-control professionals who have expertise in pediatric health care epidemiology and infection control. The PSIG requests that the American Academy of Pediatrics subcommittee clarify and reconsider its recommendations regarding the target population for the guideline, viral diagnostic testing, and interventions for preventing transmission of respiratory syncytial virus (RSV) and other viral agents that are associated with bronchiolitis, especially in inpatient settings. Although it was stated that the guideline applies to the management of bronchiolitis in healthy children, it is important to note that the absence of an identified underlying condition does not necessarily imply that hospitalized children with bronchiolitis are otherwise healthy. Severe bronchiolitis may be an … Address correspondence to Jo-Ann S. Harris, MD, Division of Infectious Disease, Pediatric Special Interest Group of the Society for Healthcare Epidemiology of America, Department of Pediatrics, MS 4004, 3901 Rainbow Blvd, Kansas City, KS 66160. E-mail: jharris7{at}kumc.edu