Clinical characteristics and risk factors of severe respiratory syncytial virus-associated acute lower respiratory tract infections in hospitalized infants

Necrotizing Enterocolitis Complicating Severe RSV Bronchiolitis in PICU Settings

This retrospective study aims to analyze the baseline characteristics and factors associated with poor outcomes in patients with necrotizing enterocolitis (NEC) complicating respiratory syncytial virus (RSV) infection. Using the Virtual Pediatric Systems data registry, patients under 2 years admitted to the pediatric intensive care unit (PICU) were screened. Patients with documented RSV infection and NEC, intestinal perforation, noninfectious gastroenteritis/colitis, or pneumatosis intestinalis occurring around the timing of RSV bronchiolitis diagnosis were included. Out of the screened patients, 41 were analyzed. Most patients (93%) were aged 30 days to 2 years, one-third had baseline anatomical cardiac defects, and 20% history of prematurity. Median PICU length of stay was 11.7 days. Seven patients died before hospital discharge. While not statistically significant, nonsurvivors tended to exhibit higher PRISM-3 scores, more acidemia, and lower systolic blood pressure. These findings emphasize the need for cautious assessment of gastrointestinal symptoms in critically ill patients with RSV infection.

Risk Factors for Poor Outcomes in Children Hospitalized With Virus-associated Acute Lower Respiratory Infections: A Systematic Review and Meta-analysis

BACKGROUND

Acute lower respiratory infection (ALRI) caused by respiratory viruses is among the most common causes of hospitalization and mortality in children. We aimed to identify risk factors for poor outcomes in children <5 years old hospitalized with ALRI caused by respiratory syncytial virus (RSV), influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

We searched Embase, Medline and Global Health databases and included observational studies reporting risk factors for poor outcomes (defined as use of supplemental oxygen, mechanical ventilation, intensive care unit admission, prolonged hospital stay and mortality) published between January 2011 and January 2023. Two authors independently extracted data on study characteristics, outcomes and risk factors. Due to limited data, meta-analyses were only conducted for RSV-ALRI poor outcome risk factors using random effects model when there were at least 3 studies.

RESULTS

We included 30 studies. For RSV-related ALRI, significant risk factors based on meta-analysis were: neurological disease [odds ratio (OR): 6.14; 95% confidence intervals (CIs): 2.39-15.77], Down's syndrome (5.43; 3.02-9.76), chronic lung disease (3.64; 1.31-10.09), immunocompromised status (3.41; 1.85-6.29), prematurity (2.98; 1.93-4.59), congenital heart disease (2.80; 1.84-4.24), underlying disease (2.45; 1.94-3.09), age <2 months (2.29; 1.78-2.94), age <6 months (2.08; 1.81-2.39), viral coinfection (2.01; 1.27-3.19), low birth weight (1.88; 1.19-2.95) and being underweight (1.80; 1.38-2.35). For influenza-related ALRI, chronic conditions and age 6-24 months were identified as risk factors for poor outcomes. Cardiovascular disease, immunosuppression, chronic kidney disease, diabetes and high blood pressure were reported as risk factors for mortality due to SARS-CoV-2 associated ALRI.

CONCLUSIONS

These findings might contribute to the development of guidelines for prophylaxis and management of ALRI caused by RSV, influenza and SARS-CoV-2.

Risk Factors for Severe Respiratory Syncytial Virus Infection in Hospitalized Children

BACKGROUND

RSV often leads to hospitalization, and accurate knowledge of risk factors is crucial.

METHODS

We retrospectively analyzed laboratory-confirmed RSV hospitalizations regarding pregnancy factors, birth status, cigarette smoke exposure, nutrition, social conditions, clinical presentation, and severe disease defined as a need for passive oxygen therapy (pO2Tx), the presence of pneumonia, respiratory failure, intensive care unit (ICU) transfer, and prolonged hospitalization.

RESULTS

A univariate analysis included 594 children (median age 4 months) and revealed a pO2Tx relationship with age ≤ 3 months (OR = 1.56), prematurity (OR = 1.71), being born during RSV season (OR = 1.72), smoke exposure during pregnancy (both parents (OR = 2.41, father (OR = 1.8)), dyspnea (OR = 5.09), and presence of apnea (OR = 5.81). Pneumonia was associated with maternal smoke exposure (OR = 5.01), fever (OR = 3.92), dyspnea (OR = 1.62), history of aspiration (OR = 4.63), and inversely with age ≤ 3 months (OR = 0.45). Respiratory failure was associated with prematurity (OR = 3.13) and apnea (OR = 18.78), while the lower odds were associated with older age (OR = 0.57 per month) and presence of fever (OR = 0.11). ICU transfer was associated with apnea (OR = 17.18), but an inverse association was observed with age (OR = 0.54) and fever (OR = 0.11). A prolonged hospital stay was associated with prematurity (OR = 1.76), low birth weight (OR = 2.89), aspiration (OR = 4.93), and presence of fever (OR = 1.51).

CONCLUSIONS

Age (up to 3 months), prematurity, and presence of apnea are risk factors for a severe RSV course.

Risk of Repeated Admissions for Respiratory Syncytial Virus in a Cohort of >10 000 Hospitalized Children

BACKGROUND

The objective was to describe respiratory syncytial virus (RSV) hospitalizations in Alberta, Canada over a 13-year period with an emphasis on the incidence and risk factors for repeat hospitalizations attributable to new RSV infections.

METHODS

This was a retrospective database analysis. The Alberta Health Services Discharge Abstract Database was searched for patients <5 years of age admitted to any hospital with a primary diagnosis of RSV from July 1, 2004 through June 30, 2017. Clinical characteristics were compared for children with repeat RSV admission during the same RSV season (but >30 days apart so presumably due to separate infections) compared with all other children with RSV admissions.

RESULTS

During the study period, 10 212 children had 10 967 RSV admissions. The RSV hospitalization rate was 1.6%. A total of 666 children (6.5%) were readmitted for RSV at least once during the study period, of whom 433 (4.2%) were readmitted within 30 days of the initial hospital discharge. There were 36 children (0.35%) with 2 RSV admissions >30 days apart during the same RSV season. When compared to all other children with RSV admissions, they were more likely to have congenital heart disease or to have been diagnosed with RSV pneumonia (vs bronchiolitis or upper respiratory tract infection) during their initial hospitalization.

CONCLUSIONS

The RSV hospitalization rate in children <5 years of age was 1.6%. Repeat RSV infections requiring readmission during the same RSV season occurred following only 0.35% of RSV hospitalizations.

Respiratory Syncytial Virus-Associated Acute Lower Respiratory Infections in Children With Bronchopulmonary Dysplasia: Systematic Review and Meta-Analysis

BACKGROUND

Respiratory syncytial virus (RSV) is among the most important causes of acute lower respiratory tract infection (ALRI) in young children. We assessed the severity of RSV-ALRI in children less than 5 years old with bronchopulmonary dysplasia (BPD).

METHODS

We searched for studies using EMBASE, Global Health, and MEDLINE. We assessed hospitalization risk, intensive care unit (ICU) admission, need for oxygen supplementation and mechanical ventilation, and in-hospital case fatality (hCFR) among children with BPD compared with those without (non-BPD). We compared the (1) length of hospital stay (LOS) and (2) duration of oxygen supplementation and mechanical ventilation between the groups.

RESULTS

Twenty-nine studies fulfilled our inclusion criteria. The case definition for BPD varied substantially in the included studies. Risks were higher among children with BPD compared with non-BPD: RSV hospitalization (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.7-4.2; P < .001), ICU admission (OR, 2.9; 95% CI, 2.3-3.5; P < .001), need for oxygen supplementation (OR, 4.2; 95% CI, .5-33.7; P = .175) and mechanical ventilation (OR, 8.2; 95% CI, 7.6-8.9; P < .001), and hCFR (OR, 12.8; 95% CI, 9.4-17.3; P < .001). Median LOS (range) was 7.2 days (4-23) (BPD) compared with 2.5 days (1-30) (non-BPD). Median duration of oxygen supplementation (range) was 5.5 days (0-21) (BPD) compared with 2.0 days (0-26) (non-BPD). The duration of mechanical ventilation was more often longer (>6 days) in those with BPD compared with non-BPD (OR, 11.9; 95% CI, 1.4-100; P = .02).

CONCLUSIONS

The risk of severe RSV disease is considerably higher among children with BPD. There is an urgent need to establish standardized BPD case definitions, review the RSV prophylaxis guidelines, and encourage more specific studies on RSV infection in BPD patients, including vaccine development and RSV-specific treatment.

Acute Lower Respiratory Infections Associated With Respiratory Syncytial Virus in Children With Underlying Congenital Heart Disease: Systematic Review and Meta-analysis

BACKGROUND

Respiratory syncytial virus (RSV) is the most common viral pathogen associated with acute lower respiratory infections (ALRIs), with significant childhood morbidity and mortality worldwide. Estimates reporting RSV-associated ALRI (RSV-ALRI) severity in children with congenital heart disease (CHD) are lacking, thus warranting the need to summarize the available data. We identified relevant studies to summarize the findings and conducted a meta-analysis of available data on RSV-associated ALRI hospitalizations in children aged <5 years, comparing those with underlying CHD to those without CHD.

METHODS

We conducted a systematic search of existing relevant literature and identified studies reporting hospitalization of children aged <5 years with RSV-ALRI with underlying or no CHD. We summarized the data and conducted (where possible) a random-effects meta-analysis to compare the 2 groups.

RESULTS

We included 18 studies that met our strict eligibility criteria. The risk of severe RSV-ALRI (odds ratio, 2.2; 95% confidence interval [CI], 1.6-2.8), the rate of hospitalization (incidence rate ratio, 2.8; 95% CI, 1.9-4.1), and the case-fatality ratio (risk ratio [RR], 16.5; 95% CI, 13.7-19.8) associated with RSV-ALRI was higher among children with underlying CHD as compared to those without no CHD. The risk of admission to the intensive care unit (RR, 3.9; 95% CI, 3.4-4.5), need for supplemental oxygen therapy (RR, 3.4; 95% CI, .5-21.1), and need for mechanical ventilation (RR, 4.1; 95% CI, 2.1-8.0) was also higher among children with underlying CHD.

CONCLUSION

This is the most detailed review to show more-severe RSV-ALRI among children aged <5 years with underlying CHD, especially hemodynamically significant underlying CHD, as compared those without CHD, supporting a need for improved RSV prophylactics and treatments that also have efficacy in children older than 1 year.

Does respiratory syncytial virus lower respiratory illness in early life cause recurrent wheeze of early childhood and asthma? Critical review of the evidence and guidance for future studies from a World Health Organization-sponsored meeting

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) and hospitalization in infants and children globally. Many observational studies have found an association between RSV LRTI in early life and subsequent respiratory morbidity, including recurrent wheeze of early childhood (RWEC) and asthma. Conversely, two randomized placebo-controlled trials of efficacious anti-RSV monoclonal antibodies (mAbs) in heterogenous infant populations found no difference in physician-diagnosed RWEC or asthma by treatment group. If a causal association exists and RSV vaccines and mAbs can prevent a substantial fraction of RWEC/asthma, the full public health value of these interventions would markedly increase. The primary alternative interpretation of the observational data is that RSV LRTI in early life is a marker of an underlying predisposition for the development of RWEC and asthma. If this is the case, RSV vaccines and mAbs would not necessarily be expected to impact these outcomes. To evaluate whether the available evidence supports a causal association between RSV LRTI and RWEC/asthma and to provide guidance for future studies, the World Health Organization convened a meeting of subject matter experts on February 12-13, 2019 in Geneva, Switzerland. After discussing relevant background information and reviewing the current epidemiologic evidence, the group determined that: (i) the evidence is inconclusive in establishing a causal association between RSV LRTI and RWEC/asthma, (ii) the evidence does not establish that RSV mAbs (and, by extension, future vaccines) will have a substantial effect on these outcomes and (iii) regardless of the association with long-term childhood respiratory morbidity, severe acute RSV disease in young children poses a substantial public health burden and should continue to be the primary consideration for policy-setting bodies deliberating on RSV vaccine and mAb recommendations. Nonetheless, the group recognized the public health importance of resolving this question and suggested good practice guidelines for future studies.

Respiratory Syncytial Virus and Associations With Cardiovascular Disease in Adults

Respiratory syncytial virus (RSV) is historically known for causing respiratory illness in young children, but the appreciation of its impact on older adults is growing. Studies have shown that hospitalization for respiratory illness due to RSV is complicated by cardiovascular events in 14% to 22% of adult patients, including worsening congestive heart failure, acute coronary syndrome, and arrhythmias. Additionally, underlying cardiovascular disease is associated with hospitalization in 45% to 63% of adults with confirmed RSV. In summary, patients with cardiopulmonary disease have higher rates of health care utilization for RSV-related illness and worse outcomes. Patients with cardiovascular disease likely represent an important target population for the rapidly developing field of RSV vaccines.

Respiratory syncytial virus prophylaxis in infants with congenital airway anomalies compared to standard indications and complex medical disorders

An observational study was conducted of children < 2 years who received ≥ 1 dose of palivizumab in 32 Canadian institutions from 2005 to 2017. We compared respiratory illness (RIH) and respiratory syncytial virus-related hospitalization (RSVH) hazards in children with a congenital airway anomaly (CAA) versus those prophylaxed for standard indications (SI) and serious medical disorders (SMD). Data were assembled on neonatal course, demographics, palivizumab utilization and adherence, and respiratory illness events, and analyzed using ANOVA, chi-square tests and Cox proportional hazards. Twenty-five thousand three children (1219 CAA, 3538 SMD, and 20,246 SI) were enrolled. Palivizumab adherence was 74.8% overall and similar across groups. For 2054 respiratory-related events, 1724 children were hospitalized. RIH rates were 13.6% (CAA), 9.6% (SMD), and 6.0% (SI). RSVH rates were 2.4% (CAA), 1.6% (SMD), and 1.5% (SI). After adjustment for demographic and neonatal differences, children with a CAA had a significantly increased RIH and RSVH hazard relative to SI (RIH, HR = 1.6, 95% CI 1.2-2.2, p = 0.002; RSVH, HR = 2.1, 95% CI 1.0-4.4, p = 0.037) but similar to SMD (RIH, HR = 1.3, 95% CI 0.9-1.9, p = 0.190; RSVH, HR = 1.7, 95% CI 0.7-4.1, p = 0.277).Conclusion: Children with a CAA experience higher RIH risk. RSVH hazard was similar between CAA and SMD but higher for CAA compared to SI, implying that this population requires surveillance for RSV prophylaxis. What is Known: • Children with congenital airway anomalies (CAA) are at risk for respiratory tract illness and respiratory syncytial virus-related hospitalization (RSVH) with accompanying morbidity and mortality • RSV prophylaxis may be useful in children with a CAA, but is not routinely recommended What is New: • Children with a CAA had a 1.6-2.3 fold greater risk of respiratory-related hospitalization and RSVH compared to those prophylaxed for standard, approved indications and serious medical disorders. • RSVH risk in children aged < 2 years with either upper or lower airway anomalies is similar. Children with a CAA require careful surveillance during the RSV season and prophylaxis may be appropriate.

Inter-individual variation in health and disease associated with pulmonary infectious agents

Respiratory infectious diseases resulting from bacterial or viral pathogens such as Mycobacterium tuberculosis, Streptococcus pneumoniae, respiratory syncytial virus (RSV), or influenza, are major global public health concerns. Lower respiratory tract infections are leading causes of morbidity and mortality, only behind ischemic heart disease and stroke (GBD 2015 LRI Collaborators in Lancet Infect Dis 17(11):1133–1161, 2017). Developing countries are particularly impacted by these diseases. However, while many are infected with viruses such as RSV (> 90% of all individuals are infected by age 2), only sub-populations develop severe disease. Many factors may contribute to the inter-individual variation in response to respiratory infections, including gender, age, socioeconomic status, nutrition, and genetic background. Association studies with functional single nucleotide polymorphisms in biologically plausible gene candidates have been performed in human populations to provide insight to the molecular genetic contribution to pulmonary infections and disease severity. In vitro cell models and genome-wide association studies in animal models of genetic susceptibility to respiratory infections have also identified novel candidate susceptibility genes, some of which have also been found to contribute to disease susceptibility in human populations. Genetic background may also contribute to differential efficacy of vaccines against respiratory infections. Development of new genetic mouse models such as the collaborative cross and diversity outbred mice should provide additional insight to the mechanisms of genetic susceptibility to respiratory infections. Continued investigation of susceptibility factors should provide insight to novel strategies to prevent and treat disease that contributes to global morbidity and mortality attributed to respiratory infections.

Hospitalisation of late preterm infants due to lower respiratory tract infections in Lithuania, Latvia, and Estonia: incidence, disease severity, and risk factors

Background.

By two years of age, almost all children experience at least one episode of respiratory syncytial virus (RSV) infection, the most common viral cause of hospitalisation due to lower respiratory tract infection (LRTI). We present data on LRTI hospitalisations (with a special focus on RSV), the course of illness, and LRTI hospitalisation risk factors in Lithuania, Latvia, and Estonia.

Materials and methods.

The analysed data were part of a large multinational study conducted in 23 countries (PONI). LRTI-related hospitalisations were observed during one RSV season for late premature infants (born between 33 weeks and 0 days and 35 weeks and 6 days of gestation) ≤6 months of age, who did not receive RSV prophylaxis. The potential risk factors and demographics were recorded at study enrolment and at the end of the RSV season. The primary endpoint was hospitalisation due to RSV LRTI; the secondary endpoints included severity, the course and the outcome of LRTI hospitalisations.

Results.

Out of the 291 infants enrolled in three Baltic states, 19 were hospitalised due to LRTI (6.5%). RSV testing was performed for 14 hospitalised infants; five infants had a positive test for RSV (1.7%). The majority of the hospitalised infants (94.7%) had mild or moderate respiratory illness. Male sex, O₂ dependency after birth, younger maternal age, and furred pets at home were significantly associated with an increased risk for LRTI hospitalisation.

Conclusions.

During one RSV season, the incidence of LRTI hospitalisations among late preterm infants was 6.5% and the incidence of RSV LRTI hospitalisations was 1.7%.

Etiology and Clinical Characteristics of Community-Acquired Pneumonia with Airway Malacia in Children

OBJECTIVE

The objective of this article is to study the etiology of community-acquired pneumonia in children with airway malacia.

METHODS

We retrospectively reviewed the medical records of 428 pneumonia patients. All patients underwent bronchoscopy, and bronchoalveolar lavage samples were processed for microbiological assessment.

RESULTS

In a total of 428 cases reviewed, 60 were found to have airway malacia. Pathogens were identified in 44 of the 60 specimens (73.3%), with 32 being single-pathogen infections. The most common pathogen was respiratory syncytial virus (RSV; 20%). Mixed-pathogen infections were observed in 12 patients. Airway malacia patients were younger than those without malacia (10.5 vs. 50 months, respectively; p < 0.001). Compared with those without airway malacia, wheezing, cyanosis and admission to the pediatric intensive care unit were more common in children with airway malacia and their hospital stay was longer.

CONCLUSION

RSV was the most common pathogen in those with airway malacia. Airway malacia was found to aggravate infectious pneumonia.

Molecular epidemiology of human respiratory syncytial virus among children in Japan during three seasons and hospitalization risk of genotype ON1

We investigated the genetic diversity, the circulation patterns, and risk for hospital admission of human respiratory syncytial virus (HRSV) strains in Japan between 2012 through 2015. During the study period, 744 HRSV-positive cases were identified by rapid diagnostic test. Of these, 572 samples were positive by real-time PCR; 400 (69.9%) were HRSV-A, and 172 (30.1%) were HRSV-B. HRSV-A and -B alternated as the dominant strain in the subsequent seasons. Phylogenetic tree analysis of the second hyper-variable region of the G protein classified the HRSV-A specimens into NA1 (n = 242) and ON1 (n = 114) genotypes and the HRSV-B specimens into BA9 (n = 60), and BA10 (n = 27). The ON1 genotype, containing a 72-nucleotide duplication in the G protein’s second hyper-variable region, was first detected in the 2012–2013 season but it predominated and replaced the older NA1 HRSV-A in the 2014–2015 season, which also coincided with a record number of HRSV cases reported to the National Infectious Disease Surveillance in Japan. The risk of hospitalization was 6.9 times higher for the ON1 genotype compared to NA1. In conclusion, our data showed that the emergence and predominance of the relatively new ON1 genotype in Japan was associated with a record high number of cases and increased risk for hospitalization.

Comparing First- and Second-year Palivizumab Prophylaxis in Patients With Hemodynamically Significant Congenital Heart Disease in the CARESS Database (2005-2015)

BACKGROUND

Respiratory syncytial virus hospitalization (RSVH) rates in children <2 years of age with hemodynamically significant congenital heart disease (HSCHD) are 2- to 4-fold higher compared with healthy term infants. Pediatric recommendations differ as to whether palivizumab is beneficial beyond 1 year of age. The objective of this study was to determine whether differences exist in respiratory-related illness hospitalization (RIH) and RSVH in HSCHD infants receiving palivizumab during the first year versus second year of life in the Canadian Registry of Palivizumab.

METHODS

The Canadian Registry of Palivizumab is a prospective database of infants who received ≥1 dose of palivizumab in 32 hospitals from 2005 to 2015. Demographic data were collected at enrollment and RIH events recorded monthly. Infants <24 months of age with HSCHD were recruited.

RESULTS

Of 1909 HSCHD infants, 1380 (72.3%) in the first year (mean age, 4.2 months) and 529 (27.7%) in the second year of life (mean age, 17.8 months) received prophylaxis. Baseline demographics for day-care attendance, multiple births, enrollment age and weight differed between the groups (all P < 0.05). Additionally, second year infants had a more complicated neonatal course, with significantly longer length of stay (51.2 vs. 24.9 days) compared with those in the first year. The RIH and RSVH rates in the first year were 11.2% and 2.3% and in the second year were 10.6% and 1.7%. Cox regression analysis showed similar hazard for RIH [hazard ratio, 1.9; 95% confidence interval: 0.7-4.6; P = 0.18] and RSVH [hazard ratio, 2.0; 95% confidence interval: 0.2-16.5; P = 0.52].

CONCLUSIONS

Infants in the first and second year of life had a similar RSVH hazard. These findings suggest that infants in the second year with HSCHD, who remain unstable, are equally at risk for RSVH and merit prophylaxis.

Respiratory syncytial virus hospitalization and mortality: Systematic review and meta-analysis

BACKGROUND

Respiratory syncytial virus (RSV) is a major public health burden worldwide. We aimed to review the current literature on the incidence and mortality of severe RSV in children globally.

METHODS

Systematic literature review and meta-analysis of published data from 2000 onwards, reporting on burden of acute respiratory infection (ARI) due to RSV in children. Main outcomes were hospitalization for severe RSV-ARI and death.

RESULTS

Five thousand two hundred and seventy-four references were identified. Fifty-five studies were included from 32 countries. The global RSV-ARI hospitalization estimates, reported per 1,000 children per year (95% Credible Interval (CrI), were 4.37 (2.98, 6.42) among children <5 years, 19.19 (15.04, 24.48) among children <1 year, 20.01 (9.65, 41.31) among children <6 months and 63.85 (37.52, 109.70) among premature children <1 year. The RSV-ARI global case-fatality estimates, reported per 1,000 children, (95% Crl) were 6.21 (2.64, 13.73) among children <5 years, 6.60 (1.85, 16.93) for children <1 year, and 1.04 (0.17, 12.06) among preterm children <1 year.

CONCLUSIONS

A substantial proportion of RSV-associated morbidity occurs in the first year of life, especially in children born prematurely. These data affirm the importance of RSV disease in the causation of hospitalization and as a significant contributor to pediatric mortality and further demonstrate gestational age as a critical determinant of disease severity. An important limitation of case-fatality ratios is the absence of individual patient characteristics of non-surviving patients. Moreover, case-fatality ratios cannot be translated to population-based mortality. Pediatr Pulmonol. 2017;52:556-569. © 2016 The Authors. Pediatric Pulmonology. Published by Wiley Periodicals, Inc.

Down syndrome as risk factor for respiratory syncytial virus hospitalization: A prospective multicenter epidemiological study

BACKGROUND

Respiratory syncytial virus (RSV) infection in childhood, particularly in premature infants, is associated with significant morbidity and mortality.

OBJECTIVES

To compare the hospitalization rates due to RSV infection and severity of disease between infants with and without Down syndrome (DS) born at term and without other associated risk factors for severe RSV infection.

PATIENTS/METHODS

In a prospective multicentre epidemiological study, 93 infants were included in the DS cohort and 68 matched by sex and data of birth (±1 week) and were followed up to 1 year of age and during a complete RSV season.

RESULTS

The hospitalization rate for all acute respiratory infection was significantly higher in the DS cohort than in the non-DS cohort (44.1% vs 7.7%, P<.0001). Hospitalizations due to RSV were significantly more frequent in the DH cohort than in the non-DS cohort (9.7% vs 1.5%, P=.03). RSV prophylaxis was recorded in 33 (35.5%) infants with DS. The rate of hospitalization according to presence or absence of RSV immunoprophylaxis was 3.0% vs 15%, respectively.

CONCLUSIONS

Infants with DS showed a higher rate of hospitalization due to acute lower respiratory tract infection and RSV infection compared to non-DS infants. Including DS infants in recommendations for immunoprophylaxis of RSV disease should be considered.

Etiology of severe pneumonia in Ecuadorian children

BACKGROUND

In Latin America, community-acquired pneumonia remains a major cause of morbidity and mortality among children. Few studies have examined the etiology of pneumonia in Ecuador.

METHODS

This observational study was part of a randomized, double blind, placebo-controlled clinical trial conducted among children aged 2-59 months with severe pneumonia in Quito, Ecuador. Nasopharyngeal and blood samples were tested for bacterial and viral etiology by polymerase chain reaction. Risk factors for specific respiratory pathogens were also evaluated.

RESULTS

Among 406 children tested, 159 (39.2%) had respiratory syncytial virus (RSV), 71 (17.5%) had human metapneumovirus (hMPV), and 62 (15.3%) had adenovirus. Streptococcus pneumoniae was identified in 37 (9.2%) samples and Mycoplasma pneumoniae in three (0.74%) samples. The yearly circulation pattern of RSV (P = 0.0003) overlapped with S. pneumoniae, (P = 0.03) with most cases occurring in the rainy season. In multivariable analysis, risk factors for RSV included younger age (adjusted odds ratio [aOR] = 1.9, P = 0.01) and being underweight (aOR = 1.8, P = 0.04). Maternal education (aOR = 0.82, P = 0.003), pulse oximetry (aOR = 0.93, P = 0.005), and rales (aOR = 0.25, P = 0.007) were associated with influenza A. Younger age (aOR = 3.5, P = 0.007) and elevated baseline respiratory rate were associated with HPIV-3 infection (aOR = 0.94, P = 0.03).

CONCLUSION

These results indicate the importance of RSV and influenza, and potentially modifiable risk factors including undernutrition and future use of a RSV vaccine, when an effective vaccine becomes available.

TRIAL REGISTRATION

ClinicalTrials.gov NCT 00513929.

Clinical and Epidemiologic Characteristics of Hospitalized Patients with Laboratory-Confirmed Respiratory Syncytial Virus Infection in Eastern China between 2009 and 2013: A Retrospective Study

Respiratory syncytial virus (RSV) is a leading cause of morbidity and mortality worldwide in children aged <5 years and older adults with acute lower respiratory infections (ALRIs). However, few studies regarding the epidemiology of hospitalizations for RSV infection have been performed previously in China. Here, we aimed to describe the clinical and epidemiologic characteristics of hospitalized patients with laboratory-confirmed RSV infection in eastern China. Active surveillance for hospitalized ALRI patients using a broad case definition based on symptoms was performed from 2009–2013 in 12 sentinel hospitals in eastern China. Clinical and epidemiologic data pertaining to hospitalized patients of all ages with laboratory-confirmed RSV infection by PCR assay were collected and analyzed in this study. From 2009 to 2013, 1046 hospitalized patients with laboratory-confirmed RSV infection were enrolled in this study, and 14.7% of patients had subtype A, 24.2% of patients had subtype B, 23.8% of patients with subtype not performed, and 37.3% of patients had RSV coinfections with other viruses. RSV and influenza coinfections (33.3%) were the most common coinfections noted in this study. Moreover, young children aged <5 years (89.1%, 932/1046), particularly young infants aged <1 year (43.3%, 453/1046), represented the highest proportion of patients with RSV infections. In contrast, older adults aged ≥60 years (1.1%, 12/1046) represented the lowest proportion of patients with RSV infections among enrolled patients. The peak RSV infection period occurred mainly during autumn and winter, and 57% and 66% of patients exhibited symptoms such as fever (body temperature ≥38°C) and cough separately. Additionally, only a small number of patients were treated with broad-spectrum antiviral drugs, and most of patients were treated with antimicrobial drugs that were not appropriate for RSV infection. RSV is a leading viral pathogen and a common cause of viral infection in young children aged <5 years with ALRIs in eastern China. Effective vaccines and antiviral agents targeting RSV are needed to mitigate its large public health impact.

Predictors of RSV LRTI Hospitalization in Infants Born at 33 to 35 Weeks Gestational Age: A Large Multinational Study (PONI)

BACKGROUND

Preterm infants are at high risk of developing respiratory syncytial virus (RSV)-associated lower respiratory tract infection (LRTI). This observational epidemiologic study evaluated RSV disease burden and risk factors for RSV-associated LRTI hospitalization in preterm infants 33 weeks+0 days to 35 weeks+6 days gestational age not receiving RSV prophylaxis.

METHODS

Preterm infants ≤6 months of age during RSV season (1 October 2013-30 April 2014) were followed at 72 sites across 23 countries from September 2013-July 2014 (study period). RSV testing was performed according to local clinical practice. Factors related to RSV-associated hospitalization for LRTI were identified using multivariable logistic regression with backward selection.

RESULTS

Of the 2390 evaluable infants, 204 and 127 were hospitalized for LRTI during the study period and RSV season, respectively. Among these subjects, 64/204 and 46/127, respectively, were hospitalized for confirmed RSV LRTI. Study period and RSV season normalized RSV hospitalization rates (per 100 infant years) were 4.1 and 6.1, respectively. Factors associated with an increased risk of RSV-related LRTI hospitalization in multivariable analyses were smoking of family members (P<0.0001), non-hemodynamically significant congenital heart disease diagnosis (P = 0.0077), maternal age of ≤25 years at delivery (P = 0.0009), low maternal educational level (P = 0.0426), household presence of children aged 4 to 5 years (P = 0.0038), age on 1 October ≤3 months (P = 0.0422), and presence of paternal atopy (P<0.0001).

CONCLUSIONS

During the 2013-2014 RSV season across 23 countries, for preterm infants 33-35 weeks gestation ≤6 months old on 1 October not receiving RSV prophylaxis, confirmed RSV LRTI hospitalization incidence was 4.1 per 100 infant years during the study period and 6.1 per 100 infant years during the RSV season. This study enhances the findings of single-country studies of common risk factors for severe RSV infection in preterm infants and suggests that combinations of 4-6 risk factors may be used to accurately predict risk of RSV hospitalization. These findings may be useful in the identification of infants most at risk of severe RSV infection.

Clinical characterisation and phylogeny of respiratory syncytial virus infection in hospitalised children at Red Cross War Memorial Children's Hospital, Cape Town

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in young children in both the community and hospital setting.

METHODS

The clinical presentation, patient and phylogenetic characteristicsof laboratory-confirmed cases of RSV, as well as risk factors for nosocomial infectionat Red Cross War Memorial Children's Hospital in Cape Town were analysed. A multiplex PCR assay that detects 7 respiratory viruses was used to identify RSV nucleic acid on respiratory specimens.

RESULTS

A total of 226 children were studied, ages ranging between 1 week and 92.5 months (median: 2.8 months, IQR: 1.3-6.3 months) and 51.8 % were males. The median duration of symptoms prior to diagnosis was 2 days (IQR: 1-4 days). Nosocomial infections wereidentified in 22 (9.7 %) children. There were pre-existing medical conditions in 113 (50.0 %) excluding HIV, most commonly prematurity (n = 58, 50.0 %) and congenital heart disease (n = 34, 29.3 %). The commonest presenting symptoms were cough (196, 86.7 %), difficulty in breathing (115, 50.9 %) and fever (91, 41.6 %).A case fatality rate of 0.9 % was recorded. RSV group A predominated (n = 181, 80.1 %) while group B accounted for only 45 (19.9 %) of the infections. The prevalent genotypes were NA1 (n = 127,70.1 %), ON1 (n = 45,24.9 %) and NA2 (n = 9,5.0 %) for group A while the only circulating RSV B genotype was BA4. There was no significant difference in the genotype distribution between the nosocomial and community-acquired RSV infections. Age ≥ 6 months was independently associated with nosocomial infection.

CONCLUSIONS

A large percentage of children with RSV infection had pre-existing conditions. Approximately one tenth of the infections were nosocomial with age 6 months or older being a risk factor. Though both RSV groups co-circulated during the season, group A was predominant and included the novel ON1 genotype. Continued surveillance is necessary to identify prevalent and newly emerging genotypes ahead of vaccine development and efficacy studies.

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

AIM

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

METHODS

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

FINDINGS

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

CONCLUSION

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