Respiratory Viral Infections In Infants Research Articles

Опыт проведения пассивной иммунизации против респираторно-синцитиальной вирусной инфекции — двенадцатый сезон

Respiratory syncytial virus (RSV) is the most common pathogenic agent responsible for respiratory viral infections in infants and young children. Therefore, the importance of research in the field has been driven by the need for effective preventive tools against RSV infection for children, especially those at high risk of severe RSV disease. Despite the on-going efforts to develop RSV vaccines, the passive immunization of children with a drug called palivizumab is the only reliable option for prophylactic use against RSV. The article presents data on the passive immunization carried out in Moscow in the 2021–2022 season, including the following: the patient routing, indications for immunization, and the organization of the immunization process. It also provides authors’ own data on the number of immunized preterm children born with low and extremely low birth weight which were collected during 11 immunization seasons. The article also reviews the structure of morbidity in this group of children. The authors emphasize a high prevalence of the comorbidity of respiratory and cardiovascular diseases. KEYWORDS: respiratory syncytial virus, preterm infants, very low body weight, very low birth weight (VLBW), extremely low birth weight (ELBW), bronchopulmonary dysplasia, immunoprophylaxis, palivizumab. FOR CITATION: Mironova A.K. The experience of passive immunization against respiratory syncytial viral infection: the twelfth season. Russian Medical Inquiry. 2022;6(11):659–666 (in Russ.). DOI: 10.32364/2587-6821-2022-6-11-659-666.

Monocytes Contribute to IFN-β Production via the MyD88-Dependent Pathway and Cytotoxic T-Cell Responses against Mucosal Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) is the leading cause of respiratory viral infection in infants and children. However, little is known about the contribution of monocytes to antiviral responses against RSV infection. We identified the IFN-β production of monocytes using IFN-β/YFP reporter mice. The kinetic analysis of IFN-β-producing cells in in vivo RSV-infected lung cells indicated that monocytes are recruited to the inflamed lung during the early phase of infection. These cells produced IFN-β via the myeloid differentiation factor 88-mediated pathway, rather than the TLR7- or mitochondrial antiviral signaling protein-mediated pathway. In addition, monocyte-ablated mice exhibited decreased numbers of IFN-γ-producing and RSV Ag-specific CD8+ T cells. Collectively, these data indicate that monocytes play pivotal roles in cytotoxic T-cell responses and act as type I IFN producers during RSV infection.

Vitamin A deficiency impairs the immune response to intranasal vaccination and RSV infection in neonatal calves

Respiratory syncytial virus (RSV) infection is a leading cause of severe acute lower respiratory tract infection in infants and children worldwide. Vitamin A deficiency (VAD) is one of the most prevalent nutrition-related health problems in the world and is a significant risk factor in the development of severe respiratory infections in infants and young children. Bovine RSV (BRSV) is a primary cause of lower respiratory tract disease in young cattle. The calf model of BRSV infection is useful to understand the immune response to human RSV infection. We have previously developed an amphiphilic polyanhydride nanoparticle (NP)-based vaccine (i.e., nanovaccine) encapsulating the fusion and attachment proteins from BRSV (BRSV-NP). Calves receiving a single, intranasal dose of the BRSV-NP vaccine are partially protected from BRSV challenge. Here, we evaluated the impact of VAD on the immune response to the BRSV-NP vaccine and subsequent challenge with BRSV. Our results show that VAD calves are unable to respond to the mucosal BRSV-NP vaccine, are afforded no protection from BRSV challenge and have significant abnormalities in the inflammatory response in the infected lung. We further show that acute BRSV infection negatively impacts serum and liver retinol, rendering even well-nourished individuals susceptible to VAD. Our results support the use of the calf model for elucidating the impact of nutritional status on mucosal immunity and respiratory viral infection in infants and underline the importance of VA in regulating immunity in the respiratory mucosa.

Plasmacytoid Dendritic Cells Contribute to the Production of IFN-β via TLR7-MyD88-Dependent Pathway and CTL Priming during Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) is the leading cause of respiratory viral infection in infants and children, yet little is known about the antiviral response of plasmacytoid dendritic cells (pDCs) to RSV infection. We tracked the cellular source of interferon-β using interferon-β/yellow fluorescent protein (YFP) reporter mice and identified the signaling pathway activated by RSV that induces type I interferon production in pDCs and DCs. Results from in vitro analyses of RSV-stimulated bone marrow cells revealed that RSV induces interferon-β production in both pDCs and DCs. Kinetic analyses of interferon-β-producing cells in RSV-infected lung cells in vivo indicated that pDCs are rapidly recruited to sites of inflammation during infection. These cells produced interferon-β via the TLR7-MyD88-mediated pathway and IFNα1R-mediated pathway rather than the MAVS-mediated pathway. Moreover, pDC-ablated mice exhibited decreased interferon-γ production and the antigen specificity of CD8+ T cells. Collectively, these data indicate that pDCs play pivotal roles in cytotoxic T lymphocyte (CTL) responses and are one of producers of type I interferon during RSV infection.

Early respiratory viral infections in infants with cystic fibrosis

BackgroundViral infections contribute to morbidity in cystic fibrosis (CF), but the impact of respiratory viruses on the development of airway disease is poorly understood. MethodsInfants with CF identified by newborn screening were enrolled prior to 4 months of age to participate in a prospective observational study at 4 centers. Clinical data were collected at clinic visits and weekly phone calls. Multiplex PCR assays were performed on nasopharyngeal swabs to detect respiratory viruses during routine visits and when symptomatic. Participants underwent bronchoscopy with bronchoalveolar lavage (BAL) and a subset underwent pulmonary function testing. We present findings through 8.5 months of life. ResultsSeventy infants were enrolled, mean age 3.1 ± 0.8 months. Rhinovirus was the most prevalent virus (66%), followed by parainfluenza (19%), and coronavirus (16%). Participants had a median of 1.5 viral positive swabs (range 0–10). Past viral infection was associated with elevated neutrophil concentrations and bacterial isolates in BAL fluid, including recovery of classic CF bacterial pathogens. When antibiotics were prescribed for respiratory-related indications, viruses were identified in 52% of those instances. ConclusionsEarly viral infections were associated with greater neutrophilic inflammation and bacterial pathogens. Early viral infections appear to contribute to initiation of lower airway inflammation in infants with CF. Antibiotics were commonly prescribed in the setting of a viral infection. Future investigations examining longitudinal relationships between viral infections, airway microbiome, and antibiotic use will allow us to elucidate the interplay between these factors in young children with CF.

Primary and Repeated Respiratory Viral Infections Among Infants in Rural Nepal.

BackgroundRespiratory viruses cause significant morbidity and death in infants; 99% of such deaths occur in resource-limited settings. Risk factors for initial and repeated respiratory viral infections in young infants in resource-limited settings have not been well described.MethodsFrom 2011 to 2014, a birth cohort of infants in rural Nepal was enrolled and followed with weekly household-based active surveillance for respiratory symptoms until 6 months of age. Respiratory illness was defined as having any of the following: fever, cough, wheeze, difficulty breathing, and/or a draining ear. We tested nasal swabs of infants with respiratory illness for multiple respiratory viruses by using a reverse transcription polymerase chain reaction assay. The risk of primary and repeated infections with the same virus was evaluated using Poisson regression.ResultsOf 3528 infants, 1726 (49%) had a primary infection, and 419 (12%) had a repeated infection. The incidences of respiratory viral infection in infants were 1816 per 1000 person-years for primary infections and 1204 per 1000 person-years for repeated infection with the same virus. Exposure to other children and male sex were each associated with an increased risk for primary infection (risk ratios, 1.13 [95% confidence interval (CI), 1.06–1.20] and 1.14 [95% CI, 1.02–1.27], respectively), whereas higher maternal education was associated with a decreased risk for both primary and repeated infections (risk ratio, 0.96 [95% CI, 0.95–0.98]). The incidence of subsequent infection did not change when previous infection with the same or another respiratory virus occurred. Illness duration and severity were not significantly different in the infants between the first and second episodes for any respiratory virus tested.ConclusionsIn infants in rural Nepal, repeated respiratory virus infections were frequent, and we found no decrease in illness severity with repeated infections and no evidence of replacement with another virus. Vaccine strategies and public health interventions that provide durable protection in the first 6 months of life could decrease the burden of repeated infections by multiple respiratory viruses, particularly in low-resource countries.

Viral Respiratory Infections in the Neonatal Intensive Care Unit-A Review.

Although infrequent, respiratory viral infections (RVIs) during birth hospitalization have a significant impact on short- and long-term morbidity in term and preterm neonates. RVI have been associated with increased length of hospital stay, severe disease course, unnecessary antimicrobial exposure and nosocomial outbreaks in the neonatal intensive care unit (NICU). Virus transmission has been described to occur via health care professionals, parents and other visitors. Most at risk are infants born prematurely, due to their immature immune system and the fact that they stay in the NICU for a considerable length of time. A prevalence of RVIs in the NICU in symptomatic infants of 6–30% has been described, although RVIs are most probably underdiagnosed, since testing for viral pathogens is not performed routinely in symptomatic patients in many NICUs. Additional challenges are the wide range of clinical presentation of RVIs, their similarity to bacterial infections and the unreliable detection methods prior to the era of molecular biology based technologies. In this review, current knowledge of early-life RVI in the NICU is discussed. Reviewed viral pathogens include human rhinovirus, respiratory syncytial virus and influenza virus, and discussed literature is restricted to reports based on modern molecular biology techniques. The review highlights therapeutic approaches and possible preventive strategies. Furthermore, short- and long-term consequences of RVIs in infants hospitalized in the NICU are discussed.

Respiratory Testing and Hospital Outcomes in Asymptomatic Infants Undergoing Heart Surgery.

Respiratory viral infections in infants undergoing congenital heart surgery lead to prolonged intubation time, hospital (HLOS) and cardiac intensive care unit length of stay (CICU LOS). The objective of this study was to evaluate the prevalence of respiratory viruses using molecular testing in otherwise healthy infants presenting for low complexity heart surgery, and to evaluate the impact of a positive viral screen and study questionnaire on post-surgical HLOS, CICU LOS, intubation time, respiratory complications, and oxygen therapy at home discharge. Sixty-nine infants (1 month to 1 year) undergoing cardiac surgery from November to May of the years 2012 to 2014 were prospectively enrolled, surveyed and tested. We compared the outcomes of positive molecular testing and positive study questionnaire to test negative subjects. We also evaluated the predictive value of study questionnaire in identification of viruses by molecular testing. Of the 69 enrolled infants, 58 had complete information available for analysis. 17 (30%) infants tested positive by molecular testing for respiratory pathogens. 38 (65%) had a “positive” questionnaire. Among the 20 viruses detected, Human Rhinovirus was the most common 12 (60%). Seven (12%) of the 58 patients developed respiratory symptoms following surgery prompting molecular testing. Four of these tested positive for a respiratory virus post-surgically. Neither positive molecular testing nor a positive questionnaire prior to surgery was associated with greater post-operative HLOS, CICU LOS, intubation time, respiratory complications, or use of oxygen at discharge compared to negative testing. The questionnaire poorly predicted positive molecular testing. Routine screening for respiratory viruses in asymptomatic infants may not be an effective strategy to predict infants at risk of post-operative complications.

Respiratory viral infections in infants with possible sepsis

BackgroundKnowledge of infections leading to sepsis is needed to develop comprehensive infection prevention and sepsis, as well as early recognition and treatment strategies.The aim of this study was to investigate the etiology of sepsis and evaluate the proportion of respiratory viral pathogens in infants under two years of age with possible sepsis.MethodsThe prospective study was performed in two years. Multiplex reverse transcriptase polymerase chain reaction (RT‐PCR) was performed to detect viral pathogens. All patients who were included in this study had sepsis symptoms as defined by the Surviving Sepsis Campaign.ResultsWe compared 90 patients with sepsis into three groups as patients (n = 33) who had only viral positivity in nasopharyngeal swab, patients (17) had proven bacterial infection with or without viral infection, and patients (40) without the pathogen detection. Human rhinovirus (16.7%) and influenza (7.8%) were the most commonly seen viruses. A cough was more common in the viral infection group than other groups ( P = 0.02) and median thrombocyte count was lower in the bacterial infection group than the others ( P = 0.01). Patients having bacterial sepsis had the longest duration of hospitalization than the other groups ( P = 0.04). During winter and spring seaons, patients with sepsis had more viral infection; however, in summer and autumn period, patients were mostly in a state that we could not prove infection agents ( P = 0.02).ConclusionsOur results suggest that respiratory tract viruses may play an important role in patients with sepsis and they should be kept in mind, especially during winter and spring seasons. In overall infection, viral respiratory viruses as a single pathogen with a detection rate of 36.6% in sepsis etiology.

Are we missing respiratory viral infections in infants and children? Comparison of a hospital-based quality management system with standard of care

ObjectivesHospital-based surveillance of influenza and acute respiratory infections relies on International Classification of Diseases (ICD) codes and hospital laboratory reports (Standard-of-Care). It is unclear how many cases are missed with either method, i.e. remain undiagnosed/coded as influenza and other respiratory virus infections. Various influenza-like illness (ILI) definitions co-exist with little guidance on how to use them. We compared the diagnostic accuracy of standard surveillance methods with a prospective quality management (QM) programme at a Berlin children's hospital with the Robert Koch Institute. MethodsIndependent from routine care, all patients fulfilling pre-defined ILI-criteria (QM-ILI) participated in the QM programme. A separate QM team conducted standardized clinical assessments and collected nasopharyngeal specimens for blinded real-time quantitative PCR for influenza A/B viruses, respiratory syncytial virus, adenovirus, rhinovirus and human metapneumovirus. ResultsAmong 6073 individuals with ILI qualifying for the QM programme, only 8.7% (528/6073) would have undergone virus diagnostics during Standard-of-Care. Surveillance based on ICD codes would have missed 61% (359/587) of influenza diagnoses. Of baseline ICD codes, 53.2% (2811/5282) were non-specific, most commonly J06 (‘acute upper respiratory infection’). Comparison of stakeholder case definitions revealed that QM-ILI and the WHO ILI case definition showed the highest overall sensitivities (84%–97% and 45%–68%, respectively) and the CDC ILI definition had the highest sensitivity for influenza infections (36%, 95% CI 31.4–40.8 for influenza A and 48%, 95% CI 40.5–54.7 for influenza B). ConclusionsDisease-burden estimates and surveillance should account for the underreporting of cases in routine care. Future studies should explore the effect of ILI screening and surveillance in various age groups and settings. Diagnostic algorithms should be based on the WHO ILI case definition combined with targeted testing.

Transient Depletion of CD169+ Cells Contributes to Impaired Early Protection and Effector CD8+ T Cell Recruitment against Mucosal Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) is a major cause of respiratory viral infections in infants and children. Alveolar macrophages (AMs) play a crucial role in combatting airborne pathogens, strongly express CD169, and are localized in the lung alveoli. Therefore, we used CD169-diphtheria toxin receptor (DTR) transgenic mice to explore the roles of CD169+ cells in immune responses to mucosal RSV infection. The administration of diphtheria toxin to CD169-DTR mice induced specific AM depletion and reduced the recruitment of Ly6Chi monocytes. Notably, CD169+ cell depletion reduced levels of innate cytokines, such as interferon-β, IL-6, and TNF-α, in bronchoalveolar lavage fluid during RSV infection without affecting the production of proinflammatory chemokines. Moreover, the depletion of CD169+ cells increased the recruitment of inflammatory cells to the lung during the early stage of RSV infection, although not during the later stages of RSV infection. Furthermore, the depletion of CD169+ cells reduced the recruitment of effector CD8+ T cells to the lungs after RSV mucosal infection. Our findings suggest that modulating the number of CD169+ cells to enhance immune responses to RSV infection may be useful as a new therapeutic strategy.

Incidence of respiratory viral infection in infants with respiratory symptoms evaluated for late-onset sepsis.

Objective:To determine the frequency, etiology and impact of respiratory viral infection (RVI) on infants evaluated for late-onset sepsis (LOS), defined as sepsis occurring >72 h of life, in the neonatal intensive care unit.Study design:Prospective observational study conducted from 6 March 2014 to 3 May 2016 on infants evaluated for LOS. PCR viral panel performed on nasopharyngeal specimens among infants with clinical suspicion for RVI. Sequence analysis was performed to determine viral subtypes. Fisher’s exact or χ2 tests were done to determine the impact of RVI.Results:During the 26-month study, there were 357 blood cultures obtained for LOS evaluations, 29 (8%) had a respiratory virus detected. Only 88 (25%) of infants evaluated for LOS also had clinical suspicion for a respiratory viral infection. RSV (14 of 29; 48%) was the predominant virus detected. Almost all infants (13 of 14; 93%) with RSV required increased respiratory support. Antimicrobial therapy was withheld or discontinued on most infants with a virus detected (18 of 29; 62%) and in the majority where there was no confirmed bacterial co-infection (18 of 20; 90%).Conclusion:The incidence of RVI in infants being evaluated for LOS is about 8%. RVI should be considered in LOS evaluation to prevent unnecessary antibiotic therapy.

Clinical Presentation, Risk Factors, and Cross-Protection from Repeated Respiratory Viral Infections in Infants in Nepal

BackgroundGlobally, pneumonia is the leading cause of childhood mortality, and RSV is a leading cause of viral pneumonia among children. Many respiratory viruses, including RSV, parainfluenza virus types 1–4 (HPIV), and rhinovirus (HRV) have the ability to cause repeated infections throughout a person’s lifetime. However, the incidence, clinical characteristics, and risk factors associated with recurrent RSV are not well described, particularly in low and middle income countries.MethodsData were collected from a randomized trial of maternal influenza vaccination conducted in rural southern Nepal from April 2011 to May 2014. Infants were followed weekly for respiratory illness until 180 days after birth. If symptomatic, a nasal swab was collected for analysis by RT-PCR for RSV and other respiratory viruses.ResultsHRV was the leading cause of respiratory infections with an incidence of 1071 per 1000 person-years (p-y). Incidence of RSV and HPIV were 222 and 223/1000 p-y, respectively, followed by CoV, BoV, HMPV, Flu, and AdV. Male gender, maternal smoking, and having other children at home were associated with a higher risk for any respiratory viral infection. Of the 336 infants infected with RSV, 12 (3.6%) had a second RSV infection in the first six months of life. The incidence for a secondary RSV infection was lower than the incidence for a primary infection (167 vs. 222/1000 p-y, respectively). No significant differences in severity or duration of illness were noted between the first and second RSV infections. Repeated infections with HRV, HPIV, and Flu were observed in 466 (34.8%) of 1,341 infants, 12 (3.4%) of 350 infants, and 7 (4.0%) of 177 infants, respectively. Birth between June and September conferred a protective effect against repeat respiratory viral infections.ConclusionRepeated infections were observed with all the respiratory viruses tested. However, the incidence of secondary RSV infection was lower than primary infection in infants less than 6 months of age, suggesting a potential protective immune response in infants after natural infection. These data are supportive of using vaccination to protect this vulnerable population against disease.Disclosures J. Englund, Gilead: Consultant and Investigator, Research support; Chimerix: Investigator, Research support; Alios: Investigator, Research support; Novavax: Investigator, Research support; MedImmune: Investigator, Research support; GlaxoSmithKline: Investigator, Research support

POTENTIAL ROLE OF SERUM PERIOSTIN IN THE EARLY DETECTION OF BRONCHIAL ASTHMA IN CHILDREN

Respiratory viral infections in infants and preschool children are often accompanied by repeated episodes of wheezing; which is associated with an increased risk of asthma development. Mechanisms of connection between a viral infection and the subsequent development of allergic inflammation in the respiratory tract are insufficiently studied. Unfortunately; despite the existence of such connection; it is difficult to predict the risk occurrence on the basis of clinical symptoms. Determination of nitrogen oxide in the exhaled air; of the number of eosinophils in the peripheral blood and of bronchoalveolar lavage fluid as well as of IgE was suggested as predictors of allergic inflammation in the airways. But these surrogate markers in patients including children with asthma have a moderate diagnostic accuracy. Their use as a marker of airway eosinophilia can cause a significant amount of false-positive and false-negative results. Recent studies have shown that determination of serum periostin more accurately confirms eosinophilic airway inflammation. The possibility to study this marker in different variants of wheezing in children as a possible predictor of asthma development is discussed based on its reliability; stability and a small variation in determination of eosinophilic inflammation in the airways with symptoms of bronchial obstruction.

Symptomatic and Asymptomatic Respiratory Viral Infections in the First Year of Life: Association With Acute Otitis Media Development

Sensitive diagnostic assays have increased the detection of viruses in asymptomatic individuals. The clinical significance of asymptomatic respiratory viral infection in infants is unknown. High-throughput, quantitative polymerase chain reaction assays were used to detect 13 common respiratory viruses from nasopharyngeal specimens collected during 2028 visits from 362 infants followed from near birth up to 12 months of age. Specimens were collected at monthly interval (months 1-6 and month 9) and during upper respiratory tract infection (URTI) episodes. Subjects were followed closely for acute otitis media (AOM) development. Viruses were detected in 76% of 394 URTI specimens and 27% of asymptomatic monthly specimens. Rhinovirus was detected most often; multiple viruses were detected in 29% of the specimens. Generalized mixed-model analyses associated symptoms with increasing age and female sex; detection of respiratory syncytial virus (RSV), influenza, rhinovirus, metapneumovirus, and adenovirus was highly associated with symptoms. Increasing age was also associated with multiple virus detection. Overall, 403 asymptomatic viral infections in 237 infants were identified. Viral load was significantly higher in URTI specimens than asymptomatic specimens but did not differentiate cases of URTI with and without AOM complication. The rate of AOM complicating URTI was 27%; no AOM occurred following asymptomatic viral infections. AOM development was associated with increasing age and infection with RSV, rhinovirus, enterovirus, adenovirus, and bocavirus. Compared to symptomatic infection, asymptomatic viral infection in infants is associated with young age, male sex, low viral load, specific viruses, and single virus detection. Asymptomatic viral infection did not result in AOM.

Respiratory viral infections in infants with clinically suspected pertussis

Objectiveto evaluate the frequency of respiratory viral infections in hospitalized infants with clinical suspicion of pertussis, and to analyze their characteristics at hospital admission and clinical outcomes. Methodsa historical cohort study was performed in a reference service for pertussis, in which the research of respiratory viruses was also a routine for infants hospitalized with respiratory problems. All infants reported as suspected cases of pertussis were included. Tests for Bordetella pertussis (BP) (polymerase chain reaction/culture) and for respiratory viruses (RVs) (immunofluorescence) were performed. Patients who received macrolides before hospitalization were excluded. Clinical data were obtained from medical records. Resultsamong the 67 patients studied, BP tests were positive in 44%, and 26% were positive for RV. There was no etiological identification in 35%, and RV combined with BP was identified in 5%. All patients had similar demographic characteristics. Cough followed by inspiratory stridor or cyanosis was a strong predictor of pertussis, as well as prominent leukocytosis and lymphocytosis. Rhinorrhea and dyspnea were more frequent in viral infections. Macrolides were discontinued in 40% of patients who tested positive for RV and negative for BP. Conclusionthe results suggest that viral infection can be present in hospitalized infants with clinical suspicion of pertussis, and etiological tests may enable a reduction in the use of macrolides in some cases. However, the etiological diagnosis of respiratory virus infection, by itself, does not exclude the possibility of infection with BP.

Respiratory viral infections in infants with clinically suspected pertussis

Objectiveto evaluate the frequency of respiratory viral infections in hospitalized infants with clinical suspicion of pertussis, and to analyze their characteristics at hospital admission and clinical outcomes. Methodsa historical cohort study was performed in a reference service for pertussis, in which the research of respiratory viruses was also a routine for infants hospitalized with respiratory problems. All infants reported as suspected cases of pertussis were included. Tests for Bordetella pertussis (BP) (polymerase chain reaction/culture) and for respiratory viruses (RVs) (immunofluorescence) were performed. Patients who received macrolides before hospitalization were excluded. Clinical data were obtained from medical records. ResultsAmong the 67 patients studied, BP tests were positive in 44%, and 26% were positive for RV. There was no etiological identification in 35%, and RV combined with BP was identified in 5%. All patients had similar demographic characteristics. Cough followed by inspiratory stridor or cyanosis was a strong predictor of pertussis, as well as prominent leukocytosis and lymphocytosis. Rhinorrhea and dyspnea were more frequent in viral infections. Macrolides were discontinued in 40% of patients who tested positive for RV and negative for BP. Conclusionthe results suggest that viral infection can be present in hospitalized infants with clinical suspicion of pertussis, and etiological tests may enable a reduction in the use of macrolides in some cases. However, the etiological diagnosis of respiratory virus infection, by itself, does not exclude the possibility of infection with BP.

Unrecognized Viral Respiratory Tract Infections in Premature Infants during their Birth Hospitalization: A Prospective Surveillance Study in Two Neonatal Intensive Care Units

ObjectiveTo determine the frequency and effects of nosocomial respiratory viral infections (RVIs) in premature neonates, including those who may be asymptomatic.Study designWe performed a year-long surveillance for RVIs in infants <33 weeks gestational age admitted to 2 Syracuse neonatal intensive care units. Infants were enrolled within 3 days of neonatal intensive care unit admission and were sampled for RVIs until discharge using a multiplex polymerase chain reaction assay capable of detecting 17 different respiratory viruses or subtypes.ResultsTwenty-six of 50 prematurely born infants (52%) tested positive for a respiratory virus at least once during their birth hospitalization. Testing positive for a respiratory virus was significantly associated with longer length of stay (70 days vs 35 days, P = .002) and prolonged ventilatory support (51 vs 13 days, P = .002). Infants who tested positive for a respiratory virus during their birth hospitalization had more than twice the rate of developing bronchopulmonary dysplasia (P < .05).ConclusionNosocomial RVIs were frequent in our study population, despite the absence of clinical indicators of illness. Length of hospital stay was significantly longer and a diagnosis of bronchopulmonary dysplasia was more common in infants who had respiratory viruses detected.

Comparison of Clinical Manifestations of RSV, Rhinovirus and Bocavirus Infections in Children with Acute Wheezing

Purpose :The purpose of this study was to compare clinical manifestations of human bocavirus (hBoV), respiratory syncytial virus (RSV), and human rhinovirus (hRV) in children with acute wheezing. Methods :We retrospectively investigated 549 virus-positive throat swabs obtained between January 2006 and December 2008 from pediatric inpatients with acute respiratory tract disease at Kwangju Christian Hospital. Among them, 109 patients, who had lower respiratory tract infections with wheezing, were enrolled in this study. The medical records of patients with positive results were reviewed for clinical data. Results :The mean age of the patients with RSV was 7.15 months, 15.66 months in those with hRV, and 15.04 months in those with hBoV. The mean fever duration and frequency of patients with fever was 2.43 days and 47.9% for RSV, 2.86 days and 51.7% for hRV, and 3.75 days and 69.6% for hBoV. The frequency of patients with acute otitis media was 20.8% in the RSV, 20.7% in the hRV, and 13.0% in the hBoV groups. The frequency of lung infiltration on chest X-ray was 12.5% in the RSV, 20.7% in the hRV, and 47.8% in the hBoV groups. Conclusion :We compared the clinical manifestations of respiratory viral infections in infants and children with wheezing. However, further surveillance will be necessary to clarify the clinical manifestations of the viruses. [Pediatr Allergy Respir Dis(Korea) 2011;21:334-343]

Respiratory viral infections in infants: causes, clinical symptoms, virology, and immunology.

In global terms, respiratory viral infection is a major cause of morbidity and mortality. Infancy, in particular, is a time of increased disease susceptibility and severity. Early-life viral infection causes acute illness and can be associated with the development of wheezing and asthma in later life. The most commonly detected viruses are respiratory syncytial virus (RSV), rhinovirus (RV), and influenza virus. In this review we explore the complete picture from epidemiology and virology to clinical impact and immunology. Three striking aspects emerge. The first is the degree of similarity: although the infecting viruses are all different, the clinical outcome, viral evasion strategies, immune response, and long-term sequelae share many common features. The second is the interplay between the infant immune system and viral infection: the immaturity of the infant immune system alters the outcome of viral infection, but at the same time, viral infection shapes the development of the infant immune system and its future responses. Finally, both the virus and the immune response contribute to damage to the lungs and subsequent disease, and therefore, any prevention or treatment needs to address both of these factors.