Respiratory Syncytial Virus Disease Severity in Young Children

Antibody levels against respiratory syncytial virus fusion protein conformations and lack of association with life-threatening infection in previously healthy infants

BACKGROUND

Humoral immune response against the pre-fusion (pre-F) conformation of respiratory syncytial virus (RSV) F protein has been proposed to play a protective role against infection. An RSV pre-F maternal vaccine has been recently approved in several countries to protect young infants against RSV. We aimed to assess serum IgG titers against the pre-F and post-F conformations of RSV F protein and their association with life-threatening RSV disease (LTD) in previously healthy infants.

METHODS

A prospective cohort study including hospitalized infants <12 months with a first RSV infection was conducted during 2017-2019. Patients with LTD required intensive care and mechanical respiratory assistance. RSV pre-F exclusive and post-F antibody responses were determined by post-F competition and non-competition immunoassays, respectively, and neutralizing activity was measured by plaque reduction neutralization test.

RESULTS

Fifty-eight patients were included; the median age was 3.5 months and 41 % were females. Fifteen patients developed LTD. RSV F-specific antibody titers positively correlated with neutralizing antibody titers in acute and convalescent phases but, importantly, they did not associate with LTD. Acute RSV pre-F exclusive and post-F IgG titers negatively correlated with patient age (P = 0.0007 and P < 0.0001), while a positive correlation was observed between the fold changes in RSV F-specific antibody titers between convalescent and acute phase and patient age (P = 0.0014 and P < 0.0001). Infants ≤2 months exhibited significantly lower fold-changes in RSV F-specific and neutralizing antibody titers between convalescence and acute phase than older infants. Additionally, acute RSV antibody titers showed no correlation with nasal RSV load and, furthermore, nasal viral load was not associated with the development of LTD.

CONCLUSIONS

This study highlights that protection against life-threatening RSV disease is not necessarily antibody-dependent. Further characterization of the immune response against RSV and its role in protection against severe disease is important for the development of the safest possible preventive strategies.

The Prognosis in Children With Pneumonia of Respiratory Syncytial Virus Co-detection With Airway Dominant Flora

BACKGROUND

Airway bacterial microbiota influences the prognosis in children with respiratory syncytial virus infection. The study aimed to investigate the effect of the airway-dominant bacterial microbiota on disease severity in children with pneumonia of respiratory syncytial virus infection.

METHODS

A retrospective study was conducted in the Children's Hospital of Chongqing Medical University, which involved a cohort of patients with respiratory syncytial virus (RSV)-infected pneumonia from January 2012 to December 2021. Patients were assigned to a normal flora group or to a dominant flora group (with the top 5 individual bacteria) based on the nasopharyngeal aspirates culture and matched using propensity-score matching. Univariate analysis and multivariate analysis were performed to estimate the risk factors of poor prognosis in dominant flora.

RESULTS

Five thousand five hundred and twelve patients in the normal flora and 4556 in the dominant flora were included ( Escherichia coli 514, Streptococcus pneumoniae 1516, Staphylococcus aureus 506, Moraxella catarrhalis 509 and Haemophilus influenzae 1516, respectively). The dominant flora had more patients developing severe pneumonia, needing mechanical ventilation/tracheal intubation (up to 15.8% in the S. aureus ) and admission to the intensive care unit (up to 4.5% in the E. coli ) than in the normal flora (28.5% vs. 25.9%; P = 0.001; 9.8% vs. 5.4%; P < 0.001; 2.0% vs. 1.2%; P <0.001). And the hospitalization was longer in the dominant flora than in the normal flora [8 (6-9) vs. 8 (7-9) days; P < 0.001], the E. coli and S. aureus had the longest hospitalization [8 (7-10) days]. Several factors were associated with critical illness in Dominant flora according to multivariate analysis ( P < 0.001), including age (OR: 0.965; CI: 0.954-0.976; P < 0.001), anhelation (OR: 0.530; CI: 0.446-0.631; P < 0.001), disorders of consciousness (OR: 0.055; CI: 0.016-0.185; P < 0.001) as well as assisted respiration (OR: 0.115; CI: 0.097-0.138; P < 0.001), C-reactive protein >10 mg/L (OR: 0.686; CI: 0.560-0.839; P < 0.001), SpO 2 <90% (OR: 0.366; CI: 0.214-0.628; P < 0.001), pulmonary consolidation (OR: 0.511; CI: 0.364-0.717; P < 0.001) and pulmonary atelectasis (OR: 0.362; CI: 0.236-0.555; P < 0.001).

CONCLUSIONS

The airway-dominant bacterial microbiota influenced disease severity and comorbidities in children with RSV-infected pneumonia. Clinicians should pay attention to the nasopharyngeal aspirate culture, especially after detecting S. aureus and E. coli in RSV-infected children with pneumonia, closely observe the disease progression and take timely measures to avoid adverse outcomes.

In vitro antiviral effect of sulfated pectin from Mangifera indica against the infection of the viral agent of childhood bronchiolitis (Respiratory Syncytial Virus - RSV)

The Human Respiratory Syncytial Virus (RSV) is the leading cause of acute respiratory infections in children. Currently, no safe, effective, or feasible option for pharmacological management of RSV exists. Hence, plant-derived natural compounds have been explored as promising antiviral agents. Mangifera indica is a globally distributed plant with reported anti-inflammatory, cardioprotective, and antiviral activities. Our study investigated the antiviral potential of a novel pectin from M. indica peels (PMi) and its chemically sulfated derivative (PSMi) against RSV in HEp-2 cells. The compounds were characterized using Fourier-transform infrared spectroscopy and nuclear magnetic resonance (NMR). NMR analysis revealed the presence of ester and carboxylic acid groups in PMi, and sulfation resulted in a sulfation degree of 0.5. PMi and PSMi showed no cytotoxic effects even at concentrations as high as 2000 μg/mL. PSMi completely inhibited RSV infectivity (100-1.56 μg/mL, 50 % inhibitory concentration of viral infectivity = 0.77 ± 0.11 μg/mL). The mechanism of action was investigated using the 50 % tissue culture infectious dose assay. PSMi displayed virucidal activity at concentrations from 100 to 6.25 μg/mL, and a significant reduction in viral infection was observed at all treatment times. Overall, PSMi is antiviral, cell-safe, and exhibits promising potential as an RSV treatment.

Respiratory Viral Testing Rate Patterns in Young Children Attending Tertiary Care Across Western Australia: A Population-Based Birth Cohort Study

BACKGROUND

An understanding of viral testing rates is crucial to accurately estimate the pathogen-specific hospitalisation burden. We aimed to estimate the patterns of testing for respiratory syncytial virus (RSV), influenza virus, parainfluenza virus (PIV) and human metapneumovirus (hMPV) by geographical location, age and time in children <5 years old in Western Australia.

METHODS

We conducted a population-based cohort study of children born between 1 January 2010 and 31 December 2021, utilising linked administrative data incorporating birth and death records, hospitalisations and respiratory viral surveillance testing records from state-wide public pathology data. We examined within-hospital testing rates using survival analysis techniques and identified independent predictors of testing using binary logistic regression.

RESULTS

Our dataset included 46,553 laboratory tests for RSV, influenza, PIV, or hMPV from 355,021 children (52.5% male). Testing rates declined in the metropolitan region over the study period (RSV testing in infants: from 242.11/1000 child-years in 2012 to 155.47/1000 child-years in 2018) and increased thereafter. Conversely, rates increased in non-metropolitan areas (e.g., RSV in Goldfields: from 364.92 in 2012 to 504.37/1000 child-years in 2021). The strongest predictors of testing were age <12 months (adjusted odds ratio [aOR] = 2.25, 95% CI 2.20-2.31), preterm birth (<32 weeks: aOR = 2.90, 95% CI 2.76-3.05) and remote residence (aOR = 0.77, 95% CI 0.73-0.81).

CONCLUSION

These current testing rates highlight the potential underestimation of respiratory virus hospitalisations by routine surveillance and the need for estimation of the true burden of respiratory virus admissions.

Characterizing human respiratory syncytial virus among children admitted with acute respiratory tract infections from 2019 to 2022

Respiratory syncytial virus is a major causative agent of lower respiratory tract infection in children, especially infants with substantial morbidity and mortality implications. The virus undergoes continuous evolution documented by accumulation of mutations in the glycoprotein gene necessitating vigilant surveillance to provide essential data to epidemiologists and researchers involved in development of vaccines. This study was aimed to perform molecular characterization of respiratory syncytial virus (RSV) among children ≤ 5 years admitted in hospital. In the current study we observed RSV-A (2019 (n = 95) and 2021 (n = 61) seasons) and RSV-B (2022 season (n = 68)). Phylogenetic analysis revealed all RSV-A strains (n = 47) to be GA.2.3.5 and RSV-B (n = 22) were classified as GB.5.0.5a. Selection pressure analysis identified one positive (P274L/V) and one negative site (P230T) in RSV-A, while in RSV-B there was only one negatively selected site (S295). This study spanning over three seasons contributes to RSV evolutionary dynamics in India emphasizing the importance of on-going surveillance to inform effective public health strategies and vaccine development efforts.

Efficacy of budesonide/formoterol inhalation powder in treating viral pneumonia in children

BACKGROUND

Respiratory viruses are increasingly detected in children with community-acquired pneumonia. Further strategies to limit antibiotic use in children with viral pneumonia are warranted.

AIM

To explore clinical efficacy of budesonide/formoterol inhalation powder for viral pneumonia in children and its impact on cellular immunity and inflammatory factor production.

METHODS

A total of 60 children with viral pneumonia were recruited: 30 receiving budesonide/formoterol inhalation powder and 30 conventional symptomatic treatment. Outcome measures included peripheral blood levels of inflammatory cytokines, CD4+, CD8+, Th1, Th2, Th17 and Treg, clinical efficacy, and incidence of adverse reactions.

RESULTS

Compared with the control group, the observation group showed a significant reduction in interleukin-6 and high-sensitivity C-reactive protein levels after treatment. Compared with the control group, the observation group showed a significant increase in CD4+/CD8+ and Th1/Th2 levels, and a decrease in Th17/Treg levels after treatment. The total effective rates in the observation group and the control group were 93.75% and 85.00%, respectively, which was a significant difference (P = 0.003).

CONCLUSION

Budesonide/formoterol inhalation powder significantly improved therapeutic efficacy for viral pneumonia in children. The mechanism of action may be related to downregulation of the inflammatory response and improved cellular immune function.

Recent Progress toward the Discovery of Small Molecules as Novel Anti-Respiratory Syncytial Virus Agents

Respiratory syncytial virus (RSV) stands as the foremost cause of infant hospitalization globally, ranking second only to malaria in terms of infant mortality. Although three vaccines have recently been approved for the prophylaxis of adults aged 60 and above, and pregnant women, there is currently no effective antiviral drug for treating RSV infections. The only preventive measure for infants at high risk of severe RSV disease is passive immunization through monoclonal antibodies. This Perspective offers an overview of the latest advancements in RSV drug discovery of small molecule antivirals, with particular focus on the promising findings from agents targeting the fusion and polymerase proteins. A comprehensive reflection on the current state of RSV research is also given, drawing inspiration from the lessons gleaned from HCV and HIV, while also considering the impact of the recent approval of the three vaccines.

Association of disease severity and genetic variation during primary Respiratory Syncytial Virus infections

BACKGROUND

Respiratory Syncytial Virus (RSV) disease in young children ranges from mild cold symptoms to severe symptoms that require hospitalization and sometimes result in death. Studies have shown a statistical association between RSV subtype or phylogenic lineage and RSV disease severity, although these results have been inconsistent. Associations between variation within RSV gene coding regions or residues and RSV disease severity has been largely unexplored.

METHODS

Nasal swabs from children (< 8 months-old) infected with RSV in Rochester, NY between 1977-1998 clinically presenting with either mild or severe disease during their first cold-season were used. Whole-genome RSV sequences were obtained using overlapping PCR and next-generation sequencing. Both whole-genome phylogenetic and non-phylogenetic statistical approaches were performed to associate RSV genotype with disease severity.

RESULTS

The RSVB subtype was statistically associated with disease severity. A significant association between phylogenetic clustering of mild/severe traits and disease severity was also found. GA1 clade sequences were associated with severe disease while GB1 was significantly associated with mild disease. Both G and M2-2 gene variation was significantly associated with disease severity. We identified 16 residues in the G gene and 3 in the M2-2 RSV gene associated with disease severity.

CONCLUSION

These results suggest that phylogenetic lineage and the genetic variability in G or M2-2 genes of RSV may contribute to disease severity in young children undergoing their first infection.

Pediatric Respiratory Syncytial Virus Hospitalizations and Respiratory Support After the COVID-19 Pandemic

Importance

After the COVID-19 pandemic, there was a surge of pediatric respiratory syncytial virus (RSV) infections, but national data on hospitalization and intensive care unit use and advanced respiratory support modalities have not been reported.

Objective

To analyze demographics, respiratory support modes, and clinical outcomes of children with RSV infections at tertiary pediatric hospitals from 2017 to 2023.

Design, Setting, and Participants

This cross-sectional study evaluated children from 48 freestanding US children's hospitals registered in the Pediatric Health Information System (PHIS) database. Patients 5 years or younger with RSV from July 1, 2017, to June 30, 2023, were included. Each season was defined from July 1 to June 30. Prepandemic RSV seasons included 2017 to 2018, 2018 to 2019, and 2019 to 2020. The postpandemic season was delineated as 2022 to 2023.

Exposure

Hospital presentation with RSV infection.

Main Outcomes and Measures

Data on emergency department presentations, hospital or intensive care unit admission and length of stay, demographics, respiratory support use, mortality, and cardiopulmonary resuscitation were analyzed. Postpandemic season data were compared with prepandemic seasonal averages.

Results

A total of 288 816 children aged 5 years or younger (median [IQR] age, 8.9 [3.3-21.5] months; 159 348 [55.2%] male) presented to 48 US children's hospitals with RSV from July 1, 2017, to June 30, 2023. Respiratory syncytial virus hospital presentations increased from 39 698 before the COVID-19 pandemic to 94 347 after the pandemic (P < .001), with 86.7% more hospitalizations than before the pandemic (50 619 vs 27 114; P < .001). In 2022 to 2023, children were older (median [IQR] age, 11.3 [4.1-26.6] months vs 6.8 [2.6-16.8] months; P < .001) and had fewer comorbidities (17.6% vs 21.8% of hospitalized patients; P < .001) than during prepandemic seasons. Advanced respiratory support use increased 70.1% in 2022 to 2023 (9094 vs 5340; P < .001), and children requiring high-flow nasal cannula (HFNC) or noninvasive ventilation (NIV) were older than during prepandemic seasons (median [IQR] age for HFNC, 6.9 [2.7-16.0] months vs 4.6 [2.0-11.7] months; for NIV, 6.0 [2.1-16.5] months vs 4.3 [1.9-11.9] months). Comorbid conditions were less frequent after the pandemic across all respiratory support modalities (HFNC, 14.9% vs 19.1%, NIV, 22.0% vs 28.5%, invasive mechanical ventilation, 30.5% vs 38.0%; P < .001).

Conclusions and Relevance

This cross-sectional study identified a postpandemic pediatric RSV surge that resulted in markedly increased hospital volumes and advanced respiratory support needs in older children with fewer comorbidities than prepandemic seasons. These clinical trends may inform novel vaccine allocation to reduce the overall burden during future RSV seasons.

Emodin inhibits respiratory syncytial virus entry by interactions with fusion protein

Introduction

Respiratory syncytial virus (RSV) fusion (F) protein is essential for facilitating virus entry into host cells, providing a hopeful path for combating viral diseases. However, F protein inhibitors can rapidly select for viral resistance. Thus, discovering new inhibitors of F-protein is necessary to enrich the RSV drug development pipeline.

Methods

In this study, we screen 25 bioactive compounds from Chinese herbal medicines that exhibit a strong binding to the RSV-F protein using surface plasmon resonance.

Results

After screening, we found emodin could strongly bind to RSV-F protein, and could effectively curb RSV infection. Further investigations certificated that emodin specifically disrupts the attachment and internalization phases of RSV infection by targeting the RSV-F protein. In vivo studies with mice infected with RSV demonstrated that emodin effectively reduces lung pathology. This therapeutic effect is attributed to emodin's capacity to diminish pro-inflammatory cytokine production and reduce viral load in the lungs.

Discussion

In conclusion, our findings provide initial insights into the mechanism by which emodin counters RSV infection via engagement with the RSV-F protein, establishing it as a viable contender for the development of novel therapeutic agents aimed at RSV.

Seasonality, Clinical Characteristics, and Outcomes of Respiratory Syncytial Virus Disease by Subtype Among Children Aged <5 Years: New Vaccine Surveillance Network, United States, 2016-2020

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory illnesses in children. RSV can be broadly categorized into 2 major subtypes: A and B. RSV subtypes have been known to cocirculate with variability in different regions of the world. Clinical associations with viral subtype have been studied among children with conflicting findings such that no conclusive relationships between RSV subtype and severity have been established.

METHODS

During 2016-2020, children aged <5 years were enrolled in prospective surveillance in the emergency department or inpatient settings at 7 US pediatric medical centers. Surveillance data collection included parent/guardian interviews, chart reviews, and collection of midturbinate nasal plus/minus throat swabs for RSV (RSV-A, RSV-B, and untyped) using reverse transcription polymerase chain reaction.

RESULTS

Among 6398 RSV-positive children aged <5 years, 3424 (54%) had subtype RSV-A infections, 2602 (41%) had subtype RSV-B infections, and 272 (5%) were not typed, inconclusive, or mixed infections. In both adjusted and unadjusted analyses, RSV-A-positive children were more likely to be hospitalized, as well as when restricted to <1 year. By season, RSV-A and RSV-B cocirculated in varying levels, with 1 subtype dominating proportionally.

CONCLUSIONS

Findings indicate that RSV-A and RSV-B may only be marginally clinically distinguishable, but both subtypes are associated with medically attended illness in children aged <5 years. Furthermore, circulation of RSV subtypes varies substantially each year, seasonally and geographically. With introduction of new RSV prevention products, this highlights the importance of continued monitoring of RSV-A and RSV-B subtypes.

Interleukin-1β promotes human metapneumovirus replication via activating the cGAS-STING pathway

BACKGROUND

Human metapneumovirus(hMPV) is one of the most common viruses that cause acute lower respiratory tract infections. Interleukin-1β (IL-1β) has been reported to play an important role in multiple virus replication. Patients with hMPV infection have increased levels of IL-1β which reminds IL-1β is associated with hMPV infection. However, the mechanism by which IL-1β affects hMPV replication remains unclear. In this study, we explore the effect of IL-1β on hMPV replication and investigate its specific mechanism of action.

METHODS

We established an hMPV infection model through Human bronchial epithelial cells (16HBE). qRT-PCR and Western Blot were used to detect the expression levels of IL-1β, cyclic GMP-AMP synthase (cGAS), and interferon stimulating factor (STING). Regulating IL-1β expression by small interfering RNA (siRNA) or exogenous supplementary to study the influence of hMPV replication. The selective cGAS inhibitor RU.521, G150, and STING inhibitor H-151 were utilized to detect hMPV replication in 16HBE cells.

RESULTS

The level of IL-1β protein increased in a time-dependent and dose-dependent manner after hMPV infection. The mRNA and protein levels of cGAS and STING were significantly up-regulated. Knockdown of IL-1β could contribute to the decreased viral loads of hMPV. While the exogenous supplement of recombinant human IL-1β in cells, replication of hMPV was significantly increased. Additionally, the level of cGAS-STING protein expression would be affected by regulating IL-1β expression. Inhibitors of the cGAS-STING pathway led to a lower level of hMPV replication.

CONCLUSION

This study found that IL-1β could promote hMPV replication through the cGAS-STING pathway, which has the potential to serve as a candidate to fight against hMPV infection, targeting IL-1β may be an effective new strategy to restrain virus replication.

Impact of COVID-19 Nonpharmaceutical Interventions on Respiratory Syncytial Virus Infections in Hospitalized Children

BACKGROUND

Nonpharmaceutical interventions (NPIs) targeted at SARS-CoV-2 have remarkably affected the circulation of other respiratory pathogens, including respiratory syncytial virus (RSV). This study aimed to assess the changes in epidemiological and clinical characteristics of RSV infections in hospitalized children before and during the pandemic in Suzhou, China.

METHODS

We prospectively enrolled children aged < 18 years who were hospitalized in Soochow University Affiliated Children's Hospital with acute lower respiratory infection (ALRIs) from January 2018 to July 2022. Changes in epidemiological and clinical characteristics of RSV infections were analyzed.

RESULTS

Compared with the same period in 2018-2019, the difference in the overall positive rate of RSV was not statistically significant in 2020, while it increased significantly in 2021 (11.8% [662/5621] vs. 20.8% [356/1711], p < 0.001) and 2022 (9.0% [308/3406] vs. 18.9% [129/684], p < 0.001). Specifically, the positive rates declined considerably from October to December 2020 but sharply increased during the summer of 2021. Compared to prepandemic period, RSV infections were more frequently observed in older children during the pandemic. RSV-positive children exhibited milder clinical characteristics during the COVID-19 pandemic, including decreased proportion of patients with hospital stay ≥ 11 days (10.3% vs. 6.7%, p < 0.05), less requirement for oxygen therapy (13.7% vs. 6.9%, p < 0.001), and fewer cases of polypnea (12.2% vs. 9.7%, p < 0.05) and wheeze (50.1% vs. 42.9%, p < 0.001).

CONCLUSIONS

The implementation of multilayered NPIs targeted at COVID-19 has affected the activity of RSV. Ongoing monitoring of RSV is warranted as the changing RSV epidemiology can provide valuable insights for future healthcare system planning.

Predictors of severity and prolonged hospital stay of viral acute respiratory infections (ARI) among children under five years in Burkina Faso, 2016-2019

BACKGROUND

Viruses are the leading etiology of acute respiratory infections (ARI) in children. However, there is limited knowledge on drivers of severe acute respiratory infection (SARI) cases involving viruses. We aimed to identify factors associated with severity and prolonged hospitalization of viral SARI among children < 5 years in Burkina Faso.

METHODS

Data were collected from four SARI sentinel surveillance sites during October 2016 through April 2019. A SARI case was a child < 5 years with an acute respiratory infection with history of fever or measured fever ≥ 38 °C and cough with onset within the last ten days, requiring hospitalization. Very severe ARI cases required intensive care or had at least one danger sign. Oropharyngeal/nasopharyngeal specimens were collected and analyzed by multiplex real-time reverse-transcription polymerase chain reaction (rRT-PCR) using FTD-33 Kit. For this analysis, we included only SARI cases with rRT-PCR positive test results for at least one respiratory virus. We used simple and multilevel logistic regression models to assess factors associated with very severe viral ARI and viral SARI with prolonged hospitalization.

RESULTS

Overall, 1159 viral SARI cases were included in the analysis after excluding exclusively bacterial SARI cases (n = 273)very severe viral ARI cases were common among children living in urban areas (AdjOR = 1.3; 95% CI: 1.1-1.6), those < 3 months old (AdjOR = 1.5; 95% CI: 1.1-2.3), and those coinfected with Klebsiella pneumoniae (AdjOR = 1.9; 95% CI: 1.2-2.2). Malnutrition (AdjOR = 2.2; 95% CI: 1.1-4.2), hospitalization during the rainy season (AdjOR = 1.71; 95% CI: 1.2-2.5), and infection with human CoronavirusOC43 (AdjOR = 3; 95% CI: 1.2-8) were significantly associated with prolonged length of hospital stay (> 7 days).

CONCLUSION

Younger age, malnutrition, codetection of Klebsiella pneumoniae, and illness during the rainy season were associated with very severe cases and prolonged hospitalization of SARI involving viruses in children under five years. These findings emphasize the need for preventive actions targeting these factors in young children.

Respiratory Syncytial Virus-Associated Hospitalizations Among Children <5 Years Old: 2016 to 2020

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of hospitalization in US infants. Accurate estimates of severe RSV disease inform policy decisions for RSV prevention.

METHODS

We conducted prospective surveillance for children <5 years old with acute respiratory illness from 2016 to 2020 at 7 pediatric hospitals. We interviewed parents, reviewed medical records, and tested midturbinate nasal ± throat swabs by reverse transcription polymerase chain reaction for RSV and other respiratory viruses. We describe characteristics of children hospitalized with RSV, risk factors for ICU admission, and estimate RSV-associated hospitalization rates.

RESULTS

Among 13 524 acute respiratory illness inpatients <5 years old, 4243 (31.4%) were RSV-positive; 2751 (64.8%) of RSV-positive children had no underlying condition or history of prematurity. The average annual RSV-associated hospitalization rate was 4.0 (95% confidence interval [CI]: 3.8-4.1) per 1000 children <5 years, was highest among children 0 to 2 months old (23.8 [95% CI: 22.5-25.2] per 1000) and decreased with increasing age. Higher RSV-associated hospitalization rates were found in premature versus term children (rate ratio = 1.95 [95% CI: 1.76-2.11]). Risk factors for ICU admission among RSV-positive inpatients included: age 0 to 2 and 3 to 5 months (adjusted odds ratio [aOR] = 1.97 [95% CI: 1.54-2.52] and aOR = 1.56 [95% CI: 1.18-2.06], respectively, compared with 24-59 months), prematurity (aOR = 1.32 [95% CI: 1.08-1.60]) and comorbid conditions (aOR = 1.35 [95% CI: 1.10-1.66]).

CONCLUSIONS

Younger infants and premature children experienced the highest rates of RSV-associated hospitalization and had increased risk of ICU admission. RSV prevention products are needed to reduce RSV-associated morbidity in young infants.

Inpatient Rsv-Management 2016-2022: Epidemiology and Adherence to A Bronchiolitis Treatment Standard at a German University Children's Hospital

BACKGROUND

This study analyzes the RSV season 2021/2022 in a referral children's hospital, compares the epidemiology and illness severity with RSV-infected inpatients from 2016 to 2020 and audits the adherence to our internal therapy standard for RSV bronchiolitis.

MATERIAL AND METHODS

Inpatients with rtPCR-confirmed RSV infection (Jan. 2016 to Jan. 2022).

RESULTS

The audit comprises 306 RSV inpatients, on average 50 hospitalizations per year; in 03/2020, a rapid RSV Season-Offset was observed. In the winter season 2020/2021, no patient with RSV was hospitalized. Beginning in July, we noticed a rapid increase of RSV-admissions (most cases in Sept./Oct, duration until Dec. 2021; n=53). In 2021-2022, a significant larger share needed PICU admission (9.4% vs 3.2%, p=0.040). Adherence to the internal guidance was low; only 11.8% (n=36) of all patients received supportive treatment without inhalative or systemic medications, 37% of all patients received antibiotics.

CONCLUSIONS

This audit confirms the strong impact of public preventive measures directed against SARS-CoV-2 transmission on RSV epidemiology. Few weeks after easing public COVID-19 restrictions (summer 2021), RSV inpatient cases rapidly increased, lasting until Dec. 2021. The audit of bronchiolitis management revealed surprisingly low adherence to the internal guidance, despite a face-to-face educational session with the attending pediatricians in Oct. 2021. Low adherence resulted in an unnecessary exposure of RSV patients to systemic medications of questionable benefit including antibiotics.

Respiratory syncytial virus: can we still believe that after pandemic bronchiolitis is not a critical issue for public health?

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection among infants and young children, resulting in annual epidemics worldwide. Since the beginning of the COVID-19 pandemic, non-pharmacological interventions were applied, interfering with the circulation of most respiratory viruses, including RSV. The aim of this study is to analyze the RSV infection trend among hospitalized infants during the actual epidemic season (2022-2023) in comparison with the last pre-pandemic season (2018-2019), in order to outline whether significant differences emerge due to COVID-19 pandemia. We retrospectively reviewed medical data on infants hospitalized at the Bambino Gesù Children's Hospital with diagnosis of bronchiolitis in the current epidemic season and in the last pre-pandemic season, 2018-2019. RSV remains the main etiological agent of bronchiolitis in terms of frequency and severity of infections in the ongoing epidemic season. The first RSV case of the 2022-2023 season was detected at week 42 vs week 47 in the 2018-2019 season. The length of epidemic season was of 17 weeks in 2022-2023 vs 18 weeks in 2018-2019. Comparing the two seasons, age at admission was significantly higher in the current season (median age 2022-2023 65 days vs median age 2018-2019 58 days), but the disease severity was similar.       Conclusions: The 2022-2023 bronchiolitis season in Italy started earlier than the usual pre-pandemic seasons but seasonality pattern may be going back to the pre-pandemic one. This season was not more severe than the previous ones. The impact of RSV disease on health care systems and costs remains a critical issue. What is Known: • RSV is one of the major leading causes of hospitalization among children aged less than 3 months. SarsCOV2 pandemic interfered with the seasonal circulation of most respiratory viruses, Including RSV. What is New: • The 2022-2023 bronchiolitis season in Italy started and peaked earlier than the usual pre-pandemic seasons but seasonality pattern may be realigning to the pre-pandemic one. The impact of RSV disease on health care systems and costs is concerning.

Respiratory syncytial virus infection and novel interventions

The large global burden of respiratory syncytial virus (RSV) respiratory tract infections in young children and older adults has gained increased recognition in recent years. Recent discoveries regarding the neutralization-specific viral epitopes of the pre-fusion RSV glycoprotein have led to a shift from empirical to structure-based design of RSV therapeutics, and controlled human infection model studies have provided early-stage proof of concept for novel RSV monoclonal antibodies, vaccines and antiviral drugs. The world's first vaccines and first monoclonal antibody to prevent RSV among older adults and all infants, respectively, have recently been approved. Large-scale introduction of RSV prophylactics emphasizes the need for active surveillance to understand the global impact of these interventions over time and to timely identify viral mutants that are able to escape novel prophylactics. In this Review, we provide an overview of RSV interventions in clinical development, highlighting global disease burden, seasonality, pathogenesis, and host and viral factors related to RSV immunity.

Diabetes and bacterial co-infection are two independent risk factors for respiratory syncytial virus disease severity

Diabetes mellitus (DM) is common among older adults hospitalized with lower respiratory tract infection, yet information on the impact of DM on disease severity is limited. This study retrospectively analyzed 46 Turkish patients infected with respiratory syncytial virus (RSV), with information on their comorbidities, co-infection status, and symptoms. Patients are grouped into four severity levels from mild to severe, according to lung parenchymal infiltration status and oxygen level. Similar to previously published studies, we found that comorbidities of diabetes, heart failure, hypertension, co-infection of any type, bacterial co-infection, and age are associated with the disease severity. Cough is the most common symptom (89%) followed by fever (26%) and myalgia, dyspnea, and weakness (around 20%). Using a second-order analysis (two-variable regression), we identified two independent risks for disease severity, the first is represented by diabetes, and the second is represented by bacterial co-infection. We observed two patients whose more severe symptoms were not associated with an older age, but associated with a combination of diabetes and bacterial co-infection. To confirm the true causality from the statistical correlation, further studies are needed.

Economic and Clinical Outcomes of Pediatric Patients Under Two With Respiratory Syncytial Virus Infection in Thailand: A Real-world Retrospective Cohort Study

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of acute respiratory tract infection in children, including in Thailand. We conducted this study to evaluate the economic and clinical outcomes of patients <2 years old with RSV infection at a tertiary teaching hospital in Thailand.

METHODS

This was a retrospective cohort study during 2014-2021. To be eligible, patients had to report at least 1 positive RSV test and were <2 years old. Descriptive statistics were used to describe baseline characteristics, healthcare resource utilization, direct medical costs (1 US dollars [USD] = 31.98 Thai Baht) and clinical outcomes.

RESULTS

Among 1370 RSV-positive patients, 49.9% of the patients (n = 683) were hospitalized at or within 3 days of RSV diagnosis with a median length of stay of 6 days (interquartile range [IQR]: 4-9 days), 38.8% were diagnosed with RSV-related respiratory complications (n = 532) and 1.5% died during the hospitalization episode (n = 20). A total of 22.5% of hospitalized patients (n = 154) received critical care during the hospitalization episode. The median cost of each RSV episode was USD539 (IQR: USD167-USD2106) and was higher among hospitalized patients (median: USD2112; IQR: USD1379-USD3182) compared with nonhospitalized patients (median: USD167; IQR: USD112-USD276).

CONCLUSIONS

RSV infection represents a potentially important contributor to healthcare resource use and medical costs among children <2 years old in Thailand. Coupled with epidemiologic data, findings from our study will be useful to illustrate the overall economic burden associated with RSV infection among children in Thailand.

[Respiratory viral infections : Under special consideration of severe acute respiratory syndrome coronavirus 2 and influenza viruses]

Respiratory viruses cause the highest number of morbidities and deaths annually among all infectious pathogens. This article discusses the current epidemiology, pathogenesis, risk factors, and drug treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza viruses, respiratory syncytial virus (RSV), and other respiratory viruses. The SARS-CoV‑2 and influenza are preventable with vaccines and a first vaccine against RSV is available since 08/2023. For infections with SARS-CoV‑2 and influenza, a stage-specific (antiviral) drug treatment is also recommended. Due to the high and commonly underestimated disease burden caused by RSV, it must be hoped that antiviral substances will be found in the future. In patients at risk, particular attention should be paid to an adequate vaccination status against respiratory pathogens and if there is clinical suspicion of a viral airway infection, the pathogen should be promptly identified and, if necessary, specific treatment should be carried out. Now that effective vaccinations and antiviral drugs are available, the challenge is to use them for all patients at risk and thus really prevent avoidable infections, severe courses and long-term sequelae.

Infants Admitted to US Intensive Care Units for RSV Infection During the 2022 Seasonal Peak

Importance

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections (LRTIs) and infant hospitalization worldwide.

Objective

To evaluate the characteristics and outcomes of RSV-related critical illness in US infants during peak 2022 RSV transmission.

Design, Setting, and Participants

This cross-sectional study used a public health prospective surveillance registry in 39 pediatric hospitals across 27 US states. Participants were infants admitted for 24 or more hours between October 17 and December 16, 2022, to a unit providing intensive care due to laboratory-confirmed RSV infection.

Exposure

Respiratory syncytial virus.

Main Outcomes and Measures

Data were captured on demographics, clinical characteristics, signs and symptoms, laboratory values, severity measures, and clinical outcomes, including receipt of noninvasive respiratory support, invasive mechanical ventilation, vasopressors or extracorporeal membrane oxygenation, and death. Mixed-effects multivariable log-binomial regression models were used to assess associations between intubation status and demographic factors, gestational age, and underlying conditions, including hospital as a random effect to account for between-site heterogeneity.

Results

The first 15 to 20 consecutive eligible infants from each site were included for a target sample size of 600. Among the 600 infants, the median (IQR) age was 2.6 (1.4-6.0) months; 361 (60.2%) were male, 169 (28.9%) were born prematurely, and 487 (81.2%) had no underlying medical conditions. Primary reasons for admission included LRTI (594 infants [99.0%]) and apnea or bradycardia (77 infants [12.8%]). Overall, 143 infants (23.8%) received invasive mechanical ventilation (median [IQR], 6.0 [4.0-10.0] days). The highest level of respiratory support for nonintubated infants was high-flow nasal cannula (243 infants [40.5%]), followed by bilevel positive airway pressure (150 infants [25.0%]) and continuous positive airway pressure (52 infants [8.7%]). Infants younger than 3 months, those born prematurely (gestational age <37 weeks), or those publicly insured were at higher risk for intubation. Four infants (0.7%) received extracorporeal membrane oxygenation, and 2 died. The median (IQR) length of hospitalization for survivors was 5 (4-10) days.

Conclusions and Relevance

In this cross-sectional study, most US infants who required intensive care for RSV LRTIs were young, healthy, and born at term. These findings highlight the need for RSV preventive interventions targeting all infants to reduce the burden of severe RSV illness.

Influence of COVID-19 pandemic on the virus spectrum in children with respiratory infection in Xuzhou, China: a long-term active surveillance study from 2015 to 2021

BACKGROUND

To investigate the impact of the coronavirus disease 2019 (COVID-19) outbreak on the prevalence of respiratory viruses among pediatric patients with acute respiratory infections in Xuzhou from 2015-2021.

METHODS

Severe acute respiratory infection (SARI) cases in hospitalized children were collected from 2015-2021 in Xuzhou, China. Influenza virus(IFV), respiratory syncytial virus (RSV), human parainfluenza virus type 3(hPIV-3), human rhinovirus (hRV), human adenovirus(hAdV), human coronavirus(hCoV) were detected by real-time fluorescence polymerase chain reaction(RT-qPCR), and the results were statistically analyzed by SPSS 23.0 software.

RESULTS

A total of 1663 samples with SARI were collected from 2015-2021, with a male-to-female ratio of 1.67:1 and a total virus detection rate of 38.5% (641/1663). The total detection rate of respiratory viruses decreased from 46.2% (2015-2019) to 36% (2020-2021) under the control measures for COVID-19 (P < 0.01). The three viruses with the highest detection rates changed from hRV, RSV, and hPIV-3 to hRV, RSV, and hCoV. The epidemic trend of hPIV-3 and hAdV was upside down before and after control measures(P < 0.01); however, the epidemic trend of RV and RSV had not changed from 2015 to 2021(P > 0.05). After the control measures, the detection rate of hPIV-3 decreased in all age groups, and the detection rate of hCoV increased in all except the 1 ~ 3 years old group.

CONCLUSIONS

Implementing control measures for COVID-19 outbreak curbed the spread of respiratory viruses among children as a whole. However, the epidemic of RV and RSV was not affected by the COVID-19 control policy.

Diagnostic models predicting paediatric viral acute respiratory infections: a systematic review

OBJECTIVES

To systematically review and evaluate diagnostic models used to predict viral acute respiratory infections (ARIs) in children.

DESIGN

Systematic review.

DATA SOURCES

PubMed and Embase were searched from 1 January 1975 to 3 February 2022.

ELIGIBILITY CRITERIA

We included diagnostic models predicting viral ARIs in children (<18 years) who sought medical attention from a healthcare setting and were written in English. Prediction model studies specific to SARS-CoV-2, COVID-19 or multisystem inflammatory syndrome in children were excluded.

DATA EXTRACTION AND SYNTHESIS

Study screening, data extraction and quality assessment were performed by two independent reviewers. Study characteristics, including population, methods and results, were extracted and evaluated for bias and applicability using the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies and PROBAST (Prediction model Risk Of Bias Assessment Tool).

RESULTS

Of 7049 unique studies screened, 196 underwent full text review and 18 were included. The most common outcome was viral-specific influenza (n=7; 58%). Internal validation was performed in 8 studies (44%), 10 studies (56%) reported discrimination measures, 4 studies (22%) reported calibration measures and none performed external validation. According to PROBAST, a high risk of bias was identified in the analytic aspects in all studies. However, the existing studies had minimal bias concerns related to the study populations, inclusion and modelling of predictors, and outcome ascertainment.

CONCLUSIONS

Diagnostic prediction can aid clinicians in aetiological diagnoses of viral ARIs. External validation should be performed on rigorously internally validated models with populations intended for model application.

PROSPERO REGISTRATION NUMBER

CRD42022308917.

The Common Cold and Influenza in Children: To Treat or Not to Treat?

The common cold, which is mostly caused by respiratory viruses and clinically represented by the symptoms of acute respiratory viral infections (ARVI) with mainly upper respiratory tract involvement, is an important problem in pediatric practice. Due to the high prevalence, socio-economic burden, and lack of effective prevention measures (except for influenza and, partially, RSV infection), ARVI require strong medical attention. The purpose of this descriptive literature review was to analyze the current practical approaches to the treatment of ARVI to facilitate the choice of therapy in routine practice. This descriptive overview includes information on the causative agents of ARVI. Special attention is paid to the role of interferon gamma as a cytokine with antiviral and immunomodulatory effects on the pathogenesis of ARVI. Modern approaches to the treatment of ARVI, including antiviral, pathogenesis-directed and symptomatic therapy are presented. The emphasis is on the use of antibody-based drugs in the immunoprophylaxis and immunotherapy of ARVI. The data presented in this review allow us to conclude that a modern, balanced and evidence-based approach to the choice of ARVI treatment in children should be used in clinical practice. The published results of clinical trials and systematic reviews with meta-analyses of ARVI in children allow us to conclude that it is possible and expedient to use broad-spectrum antiviral drugs in complex therapy. This approach can provide an adequate response of the child’s immune system to the virus without limiting the clinical possibilities of using only symptomatic therapy.

Respiratory virus circulation during the first year of the COVID-19 pandemic in the Household Influenza Vaccine Evaluation (HIVE) cohort

Background

The annual reappearance of respiratory viruses has been recognized for decades. COVID-19 mitigation measures taken during the pandemic were targeted at respiratory transmission and broadly impacted the burden of acute respiratory illnesses (ARIs).

Methods

We used the longitudinal Household Influenza Vaccine Evaluation (HIVE) cohort in southeast Michigan to characterize the circulation of respiratory viruses from March 1, 2020, to June 30, 2021, using RT-PCR of respiratory specimens collected at illness onset. Participants were surveyed twice during the study period, and SARS-CoV-2 antibodies were measured in serum by electrochemiluminescence immunoassay. Incidence rates of ARI reports and virus detections were compared between the study period and a preceding pre-pandemic period of similar duration.

Results

Overall, 437 participants reported a total of 772 ARIs; 42.6% had respiratory viruses detected. Rhinoviruses were the most frequent virus, but seasonal coronaviruses, excluding SARS-CoV-2, were also common. Illness reports and percent positivity were lowest from May to August 2020, when mitigation measures were most stringent. Seropositivity for SARS-CoV-2 was 5.3% in summer 2020 and increased to 11.3% in spring 2021. The incidence rate of total reported ARIs for the study period was 50% lower (95% CI: 0.5, 0.6; p < 0.001) than the incidence rate from a pre-pandemic comparison period (March 1, 2016, to June 30, 2017).

Conclusions

The burden of ARI in the HIVE cohort during the COVID-19 pandemic fluctuated, with declines occurring concurrently with the widespread use of public health measures. Rhinovirus and seasonal coronaviruses continued to circulate even when influenza and SARS-CoV-2 circulation was low.

The Contribution of Viruses and Bacteria to Childhood Community-acquired Pneumonia: 11-Year Observational Study From Norway

BACKGROUND

Viruses are associated with pediatric community-acquired pneumonia (CAP) but are also common in the upper airways of healthy children. We have determined the contribution of respiratory viruses and bacteria by comparing children with CAP and hospital controls.

METHODS

Children less than 16 years old with radiologically confirmed CAP (n = 715) were enrolled over an 11-year period. Children admitted for elective surgery during the same period served as controls (n = 673). Nasopharyngeal aspirates were tested for 20 respiratory pathogens by semiquantitative polymerase chain reaction tests and cultivated for bacteria and viruses. We used logistic regression to calculate adjusted odds ratios [aOR; 95% confidence intervals (CIs)], and estimated population-attributable fractions (95% CI).

RESULTS

At least 1 virus was detected in 85% of cases and 76% of controls, and greater than or equal to 1 bacterium was detected in 70% of cases and controls. The presence of respiratory syncytial virus (RSV) (aOR, 16.6; 95% CI: 9.81-28.2), human metapneumovirus (HMPV) (13.0; 6.17-27.5) and Mycoplasma pneumonia e (27.7; 8.37-91.6) were most strongly associated with CAP. For RSV and HMPV, there were significant trends between lower cycle-threshold values indicating higher viral genomic loads, and higher aORs for CAP. The population-attributable fraction estimates of RSV, HMPV, human parainfluenza virus, influenza virus and M. pneumoniae were 33.3% (32.2-34.5), 11.2% (10.5-11.9), 3.7% (1.0-6.3), 2.3% (1.0-3.6) and 4.2% (4.1-4.4), respectively.

CONCLUSIONS

RSV, HMPV and M. pneumoniae were most strongly related to pediatric CAP and accounted for half of all cases. There were positive trends between increasing viral genomic loads of RSV and HMPV, and higher odds for CAP.

Epidemiological and clinical characteristics of respiratory syncytial virus and influenza infections in hospitalized children before and during the COVID-19 pandemic in Central China

Background

Globally, the epidemiology of non-SARS-CoV-2 respiratory viruses like respiratory syncytial virus (RSV) and influenza virus was remarkably influenced by the implementation of non-pharmacological interventions (NPIs) during the COVID-19 pandemic. Our study explored the epidemiological and clinical characteristics of pediatric patients hospitalized with RSV or influenza infection before and during the pandemic after relaxation of NPIs in central China.

Methods

This hospital-based prospective case-series study screened pediatric inpatients (age ≤ 14 years) enrolled with acute respiratory infections (ARI) for RSV or influenza infection from 2018 to 2021. The changes in positivity rates of viral detection, epidemiological, and clinical characteristics were analyzed and compared.

Results

Median ages of all eligible ARI patients from 2018-2019 were younger than those from 2020-2021, so were ages of cases infected with RSV or influenza (RSV: 4.2 months vs. 7.2 months; influenza: 27.3 months vs. 37.0 months). Where the positivity rate for influenza was considerably decreased in 2020-2021 (1.4%, 27/1964) as compared with 2018-2019 (2.9%, 94/3275, P < 0.05), it was increased for RSV (11.4% [372/3275] vs. 13.3% [262/1964], P < 0.05) in the same period. The number of severe cases for both RSV and influenza infection were also decreased in 2020-2021 compared with 2018-2019.

Conclusions

The implemented NPIs have had varied impacts on common respiratory viruses. A more effective prevention strategy for RSV infections in childhood is needed.

Association of viral load with TRAIL, IP-10, CRP biomarker signature and disease severity in children with respiratory tract infection or fever without source: A prospective, multicentre cohort study

BACKGROUND

To investigate the association of viral load (VL) with (i) tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein-10, C-reactive protein, and a combinatorial score (BV score), and (ii) clinical severity.

STUDY DESIGN

In this prospective, multicentre cohort substudy, children with respiratory tract infection or fever without source were enrolled. VL for influenza virus, rhinovirus, respiratory syncytial virus, and adenovirus was measured from nasopharyngeal swabs. The reference standard diagnosis was established based on expert panel adjudication.

RESULTS

Of 1140 recruited patients, 333 had a virus monodetection. VL for the aggregated data set correlated with TRAIL and IP-10 levels, with the length of oxygen therapy, and inversely with the BV score. At a single viral level, only the influenza VL yielded a correlation with TRAIL, IP-10 levels, and the BV score. Children with a viral reference standard diagnosis had significantly higher VL than those with bacterial infection (p = 0.0005). Low TRAIL (incidence rate ratio [IRR] 0.6, 95% confidence interval [CI] 0.39-0.91) and young age (IRR 0.62, 95% CI 0.49-0.79) were associated with a longer hospital stay, while young age (IRR 0.33, 95% CI 0.18-0.61), low TRAIL (IRR 0.25, 95% CI 0.08-0.76), and high VL (IRR 1.16, 95% CI 1.00-1.33) were predictive of longer oxygen therapy.

CONCLUSION

These findings indicate that VL correlates with biomarkers and may serve as a complementary tool pertaining to disease severity.

Type III Interferons, Viral Loads, Age, and Disease Severity in Young Children With Respiratory Syncytial Virus Infection

BACKGROUND

The interplay among respiratory syncytial virus (RSV) loads, mucosal interferons (IFN), and disease severity in RSV-infected children is poorly understood.

METHODS

Children <2 years of age with mild (outpatients) or severe (inpatients) RSV infection and healthy controls were enrolled, and nasopharyngeal samples obtained for RSV loads and innate cytokines quantification. Patients were stratified by age (0-6 and >6-24 months) and multivariable analyses performed to identify predictors of disease severity.

RESULTS

In 2015-2019 we enrolled 219 RSV-infected children (78 outpatients; 141 inpatients) and 34 healthy controls. Type I, II, and III IFN concentrations were higher in children aged >6 versus 0-6 months and, like CXCL10, they were higher in outpatients than inpatients and correlated with RSV loads (P < .05). Higher IL6 concentrations increased the odds of hospitalization (odds ratio [OR], 2.30; 95% confidence interval [CI], 1.07-5.36) only in children >6 months, while higher IFN-λ2/3 concentrations had the opposite effect irrespective of age (OR, 0.38; 95% CI, .15-.86). Likewise, higher CXCL10 concentrations decreased the odds of hospitalization (OR, 0.21; 95% CI, .08-.48), oxygen administration (OR, 0.42; 95% CI, .21-.80),PICU admission (OR, 0.39; 95% CI, .20-.73), and prolonged hospitalization (OR, 0.57; 95% CI, .32-.98) irrespective of age.

CONCLUSIONS

Children with milder RSV infection and those aged >6 months had higher concentrations of mucosal IFNs, suggesting that maturation of mucosal IFN responses are associated with protection against severe RSV disease.

Burden of Respiratory Syncytial Virus Related Acute Lower Respiratory Tract Infection in Hospitalized Thai Children: A 6-Year National Data Analysis

Objectives: This study sought to determine the epidemiology, seasonal variations, morbidity, and mortality of respiratory syncytial virus (RSV) infection among hospitalized children with lower respiratory tract infection in Thailand. In addition, we assessed the risk factors associated with severe RSV lower respiratory tract infection (LRTI)-related morbidity and mortality. Methods: The data were reviewed retrospectively from the National Health Security Office for hospitalized children younger than 18 years old diagnosed with RSV-related LRTI in Thailand, between the fiscal years of 2015 to 2020. The RSV-related LRTIs were identified using the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Thai Modification. ICD-10-TM codes J12.1, J20.5, and J21.0, which represent respiratory syncytial virus pneumonia, acute bronchitis due to respiratory syncytial virus, and acute bronchiolitis due to respiratory syncytial virus, respectively, were studied. Results: During the study period, RSV-related LRTI accounted for 19,340 of the 1,610,160 hospital admissions due to LRTI. RSV pneumonia was the leading cause of hospitalization (13,684/19,340; 70.76%), followed by bronchiolitis (2849/19,340; 14.73%) and bronchitis (2807/19,340; 14.51%), respectively. The highest peak incidence of 73.55 percent occurred during Thailand’s rainy season, from August to October. The mortality rate of RSV-related LRTI in infants younger than 1 year of age was 1.75 per 100,000 person years, which was significantly higher than that of children 1 to younger than 5 years old and children 5 to younger than 18 years old (0.21 per 100,000 person years and 0.01 per 100,000 person years, respectively, p-value < 0.001). Factors associated with mortality were congenital heart disease, hematologic malignancy, malnutrition, and neurological disease. Conclusions: In children with RSV LRTI, pneumonia was the leading cause of hospitalization. The admission rate was highest during the rainy season. Mortality from RSV-related LRTI was higher in children under 1 year old and in children with underlying illnesses; future preventive interventions should target these groups of patients.

Respiratory Virus Circulation during the First Year of the COVID-19 Pandemic in the Household Influenza Vaccine Evaluation (HIVE) Cohort

Background

The annual reappearance of respiratory viruses has been recognized for decades. The onset of the COVID-19 pandemic altered typical respiratory virus transmission patterns. COVID-19 mitigation measures taken during the pandemic were targeted at SARS-CoV-2 respiratory transmission and thus broadly impacted the burden of acute respiratory illnesses (ARIs), in general.

Methods

We used the longitudinal Household Influenza Vaccine Evaluation (HIVE) cohort of households in southeast Michigan to characterize mitigation strategy adherence, respiratory illness burden, and the circulation of 15 respiratory viruses during the COVID-19 pandemic determined by RT-PCR of respiratory specimens collected at illness onset. Study participants were surveyed twice during the study period (March 1, 2020, to June 30, 2021), and serologic specimens were collected for antibody measurement by electrochemiluminescence immunoassay. Incidence rates of ARI reports and virus detections were calculated and compared using incidence rate ratios for the study period and a pre-pandemic period of similar length.

Results

Overall, 437 participants reported a total of 772 ARIs and 329 specimens (42.6%) had respiratory viruses detected. Rhinoviruses were the most frequently detected organism, but seasonal coronaviruses-excluding SARS-CoV-2-were also common. Illness reports and percent positivity were lowest from May to August 2020, when mitigation measures were most stringent. Study participants were more adherent to mitigation measures in the first survey compared with the second survey. Supplemental serology surveillance identified 5.3% seropositivity for SARS-CoV-2 in summer 2020; 3.0% between fall 2020 and winter 2021; and 11.3% in spring 2021. Compared to a pre-pandemic period of similar length, the incidence rate of total reported ARIs for the study period was 50% lower (95% CI: 0.5, 0.6; p<0.001) than the incidence rate from March 1, 2016, to June 30, 2017.

Conclusions

The burden of ARI in the HIVE cohort during the COVID-19 pandemic fluctuated, with declines occurring concurrently with the widespread use of public health measures. It is notable, however, that rhinovirus and seasonal coronaviruses continued to circulate even as influenza and SARS-CoV-2 circulation was low.

Cilia-related gene signature in the nasal mucosa correlates with disease severity and outcomes in critical respiratory syncytial virus bronchiolitis

Background

Respiratory syncytial virus (RSV) can cause life-threatening respiratory failure in infants. We sought to characterize the local host response to RSV infection in the nasal mucosa of infants with critical bronchiolitis and to identify early admission gene signatures associated with clinical outcomes.

Methods

Nasal scrape biopsies were obtained from 33 infants admitted to the pediatric intensive care unit (PICU) with critical RSV bronchiolitis requiring non-invasive respiratory support (NIS) or invasive mechanical ventilation (IMV), and RNA sequencing (RNA-seq) was performed. Gene expression in participants who required shortened NIS (</= 3 days), prolonged NIS (> 3 days), and IMV was compared.

Findings

Increased expression of ciliated cell genes and estimated ciliated cell abundance, but not immune cell abundance, positively correlated with duration of hospitalization in infants with critical bronchiolitis. A ciliated cell signature characterized infants who required NIS for > 3 days while a basal cell signature was present in infants who required NIS for </= 3 days, despite both groups requiring an equal degree of respiratory support at the time of sampling. Infants who required invasive mechanical ventilation had increased expression of genes involved in neutrophil activation and cell death.

Interpretation

Increased expression of cilia-related genes in clinically indistinguishable infants with critical RSV may differentiate between infants who will require prolonged hospitalization and infants who will recover quickly. Validation of these findings in a larger cohort is needed to determine whether a cilia-related gene signature can predict duration of illness in infants with critical bronchiolitis. The ability to identify which infants with critical RSV bronchiolitis may require prolonged hospitalization using non-invasive nasal samples would provide invaluable prognostic information to parents and medical providers.

Age and respiratory syncytial virus etiology in bronchiolitis clinical outcomes

Background

Respiratory syncytial virus (RSV) is the most frequent cause of bronchiolitis. Precise and updated information about demographic characteristics, clinical manifestations, and risk factors for severe disease are needed for optimal implementation of upcoming new therapeutic and preventive interventions.

Objectives

The main goals of this study were to define the epidemiology of acute bronchiolitis in hospitalized young children during 5 calendar years in Spain; evaluate the differences in clinical manifestations between children hospitalized with RSV infection and those hospitalized with non-RSV infection; and identify demographic characteristics, clinical parameters, and risk factors associated with disease severity.

Methods

We performed a retrospective review of the medical records of children younger than 2 years who were hospitalized with bronchiolitis between January 2015 and December 2019. We constructed multivariable models to identify independent predictors of disease severity defined as length of hospital stay (LOS), pediatric intensive care unit (PICU) admission, and need for a high-flow-nasal canula (HFNC).

Results

From January 2015 to December 2019, 1437 children were hospitalized with bronchiolitis and met the inclusion criteria. The proportion of children hospitalized with bronchiolitis caused by RSV increased significantly during the study period, from 60% to 65% (P = .03). The children with RSV bronchiolitis were younger than those with non-RSV bronchiolitis (median age = 3 months [interquartile range = 1.5-6.5 months] vs 4 months [interquartile range = 2-7.5 months], respectively (P < .01). The children younger than 6 months with RSV bronchiolitis had enhanced disease severity compared with those with non-RSV bronchiolitis, as defined by an LOS of more than 4 days, severity scores, need for an HFNC, intravenous fluids, enteral feeding, and PICU admissions (P < .01). Age younger than 6 months and RSV-positive etiology were independently associated with greater odds of PICU admission, need for an HFNC, and longer LOS.

Conclusion

This study identified differences in disease severity between young children with RSV bronchiolitis and those with non-RSV bronchiolitis. These differences are particularly significant in children younger than 6 months, who comprise a group of infants with suboptimal innate immunity to RSV and may benefit from new preventive strategies.

Clinical Burden of Respiratory Syncytial Virus in Hospitalized Children Aged ≤5 years (INSPIRE Study)

Background

Respiratory syncytial virus (RSV) is a leading cause of hospitalizations in children (≤5 years of age); limited data compare burden by age.

Methods

This single-center retrospective study included children (≤5 years of age) hospitalized for >24 hours with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed RSV infection (2015–2018). Hospital length of stay (LOS), intensive care unit (ICU) admissions, ICU LOS, supplemental oxygen, and medication use were assessed. Multivariate logistic regression analyses identified predictors of hospital LOS >5 days.

Results

Three hundred twelve patients had RSV infection (ages 0 to <6 months [35%], 6 to <12 months [15%], 1 to <2 years [25%], and 2–5 years [25%]); 16.3% had predefined comorbidities (excludes preterm infants). Median hospital LOS was 5.0 days and similar across age; 5.1% (16/312) were admitted to ICU (ICU LOS, 5.0 days), with those aged 0 to <6 months admitted most frequently (10/108 [9.3%]). Supplemental oxygen was administered in 57.7% of patients, with similar need across ages. Antibiotics were administered frequently during hospitalization (43.6%). Predictors of prolonged LOS included pneumonia (odds ratio [OR], 2.33), supplemental oxygen need (OR, 5.09), and preterm births (OR, 3.37). High viral load (RT-PCR RSV cycle threshold value <25) was associated with greater need for supplemental oxygen.

Conclusions

RSV causes substantial burden in hospitalized children (≤5 years), particularly preterm infants and those aged <6 months.

Comparison of clinical presentations and burden of respiratory syncytial virus in infants across three distinct healthcare settings in Davidson County, Tennessee

Background

The burden of respiratory syncytial virus (RSV)-associated acute respiratory illnesses among healthy infants (<1 year) in the inpatient setting is well established. The focus on RSV-associated illnesses in the outpatient (OP) and emergency department (ED) settings are however understudied. We sought to determine the spectrum of RSV illnesses in infants at three distinct healthcare settings.

Methods

From 16 December 2019 through 30 April 2020, we performed an active, prospective RSV surveillance study among infants seeking medical attention from an inpatient (IP), ED, or OP clinic. Infants were eligible if they presented with fever and/or respiratory symptoms. Demographics, clinical characteristics, and illness histories were collected during parental/guardian interviews, followed by a medical chart review and illness follow-up surveys. Research nasal swabs were collected and tested for respiratory pathogens for all enrolled infants.

Results

Of the 627 infants screened, 475 were confirmed eligible; 360 were enrolled and research tested. Within this final cohort, 101 (28%) were RSV-positive (IP = 37, ED = 18, and OP = 46). Of the RSV-positive infants, the median age was 4.5 months and 57% had ⩾2 healthcare encounters. The majority of RSV-positive infants were not born premature (88%) nor had underlying medical conditions (92%). RSV-positive infants, however, were more likely to have a lower respiratory tract infection than RSV-negative infants (76% vs 39%, p < 0.001). Hospitalized infants with RSV were younger, 65% required supplemental oxygen, were more likely to have lower respiratory tract symptoms, and more often had shortness of breath and rales/rhonchi than RSV-positive infants in the ED and OP setting.

Conclusion

Infants with RSV illnesses seek healthcare for multiple encounters in various settings and have clinical difference across settings. Prevention measures, especially targeted toward healthy, young infants are needed to effectively reduce RSV-associated healthcare visits.

Acute Respiratory Illnesses in Children in the SARS-CoV-2 Pandemic: Prospective Multicenter Study

OBJECTIVES

Nonpharmaceutical interventions against coronavirus disease 2019 likely have a role in decreasing viral acute respiratory illnesses (ARIs). We aimed to assess the frequency of respiratory syncytial virus (RSV) and influenza ARIs before and during the coronavirus disease 2019 pandemic.

METHODS

This study was a prospective, multicenter, population-based ARI surveillance, including children seen in the emergency departments and inpatient settings in 7 US cities for ARI. Respiratory samples were collected and evaluated by molecular testing. Generalized linear mixed-effects models were used to evaluate the association between community mitigation and number of eligible and proportion of RSV and influenza cases.

RESULTS

Overall, 45 759 children were eligible; 25 415 were enrolled and tested; 25% and 14% were RSV-positive and influenza-positive, respectively. In 2020, we noted a decrease in eligible and enrolled ARI subjects after community mitigation measures were introduced, with no RSV or influenza detection from April 5, 2020, to April 30, 2020. Compared with 2016-2019, there was an average of 10.6 fewer eligible ARI cases per week per site and 63.9% and 45.8% lower odds of patients testing positive for RSV and influenza, respectively, during the 2020 community mitigation period. In all sites except Seattle, the proportions of positive tests for RSV and influenza in the 2020 community mitigation period were lower than predicted.

CONCLUSIONS

Between March and April 2020, rapid declines in ARI cases and the proportions of RSV and influenza in children were consistently noted across 7 US cities, which could be attributable to community mitigation measures against severe acute respiratory syndrome coronavirus 2.

Respiratory Virus Surveillance in Infants across Different Clinical Settings

OBJECTIVES

We aimed to evaluate the distribution, clinical presentations and severity of common acute respiratory infections (ARI) viruses in infants across 3 clinical settings.

STUDY DESIGN

In a prospective virus surveillance study, infants under 1 year with fever and/or respiratory symptoms were enrolled from outpatient, emergency department, and inpatient settings from December 16, 2019 through April 30, 2020. Demographic and clinical characteristics were collected through parent/guardian interviews, medical chart abstractions, and follow-up surveys. Nasal swabs were collected and tested for viruses using quantitative reverse-transcription polymerase chain reaction.

RESULTS

We enrolled 366 infants and tested nasal swabs on 360 (98%); median age was 6.3 months, 50% male. In total, 295 (82%) had at least 1 virus detected; rhinovirus/enterovirus (RV/EV; 42%), respiratory syncytial virus (RSV; 34%), and influenza (15%) were the most common. RSV was the most frequently detected virus in the inpatient (63%) and emergency department (37%) settings, and RV/EV was most frequently detected virus in the outpatient setting (54%). RSV-positive infants had a lower median age (4.9 months) and were more likely to have respiratory distress, and RV/EV-positive infants were less likely to have respiratory distress. Influenza-positive infants had a higher median age (8 months) and were more likely to have systemic symptoms. RSV infection and younger age were associated with higher odds of hospitalization in multivariable logistic regression.

CONCLUSIONS

Across 3 clinical settings, and combining virologic, patient, and health-system information, our results highlight the burden of viral ARI among infants. Overall, RSV, RV/EV, and influenza were most commonly detected, with RSV having the highest disease severity.

Patent highlights August-September 2020

A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.