Do early-life allergic sensitization and respiratory infection interact to increase asthma risk?

OBJECTIVE

The 'two-hit' hypothesis theorizes that early life allergic sensitization and respiratory infection interact to increase asthma risk.

METHODS

We sought to determine in a high allergy risk birth cohort whether interactions between early life allergic sensitization and respiratory infection were associated with increased risk for asthma at ages 6-7 years and 18 years. Allergic sensitization was assessed at 6, 12, and 24 months by skin prick testing to 3 food and 3 aeroallergens. Respiratory infection was defined as reported "cough, rattle, or wheeze" and assessed 4-weekly for 15 months, at 18 months, and age 2 years. Regression analysis was undertaken with parent-reported asthma at age 6-7 years and doctor diagnosed asthma at 18 years as distinct outcomes. Interactions between allergic sensitization and respiratory infection were explored with adjustment made for potential confounders.

RESULTS

Odds of asthma were higher in sensitized compared to nonsensitized children at age 6-7 years (OR = 14.46; 95% CI 3.99-52.4), There was no evidence for interactions between allergic sensitization and early life respiratory infection, with a greater frequency of respiratory infection up to 2 years of age associated with increased odds for asthma at age 6-7 years in both sensitized (OR = 1.13; 95% CI 1.02-1.25, n = 199) and nonsensitized children (OR = 1.31; 1.11-1.53, n = 211) (p interaction = 0.089). At age 18 years, these associations were weaker.

CONCLUSIONS

Our findings do not support 'two-hit' interactions between early life allergic sensitization and respiratory infection on asthma risk. Both early life respiratory infections and allergic sensitization were risk factors and children with either should be monitored closely for development of asthma.

Prevalence and Clinical Impact of Respiratory Viral Infections from the STOP2 Study of Cystic Fibrosis Pulmonary Exacerbations

Rationale: Rates of viral respiratory infection (VRI) are similar in people with cystic fibrosis (CF) and the general population; however, the associations between VRI and CF pulmonary exacerbations (PEx) require further elucidation.Objectives: To determine VRI prevalence during CF PEx and evaluate associations between VRI, clinical presentation, and treatment response.Methods: The STOP2 (Standardized Treatment of Pulmonary Exacerbations II) study was a multicenter randomized trial to evaluate different durations of intravenous antibiotic therapy for PEx. In this ancillary study, participant sputum samples from up to three study visits were tested for respiratory viruses using multiplex polymerase chain reactions. Baselines and treatment-associated changes in mean lung function (percent predicted forced expiratory volume in 1 s), respiratory symptoms (Chronic Respiratory Infection Symptom Score), weight, and C-reactive protein were compared as a function of virus detection. Odds of PEx retreatment within 30 days and future PEx hazard were modeled by logistic and Cox proportional hazards regression, respectively.Results: A total of 1,254 sputum samples from 621 study participants were analyzed. One or more respiratory viruses were detected in sputum samples from 245 participants (39.5%). Virus-positive participants were more likely to be receiving CF transmembrane conductance regulator modulator therapy (45% vs. 34%) and/or chronic azithromycin therapy (54% vs. 44%) and more likely to have received treatment for nontuberculous Mycobacterium infection in the preceding 2 years (7% vs. 3%). At study visit 1, virus-positive participants were more symptomatic (mean Chronic Respiratory Infection Symptom Score, 53.8 vs. 51.1), had evidence of greater systemic inflammation (log10 C-reactive protein concentration, 1.32 log10 mg/L vs. 1.23 log10 mg/L), and had a greater drop in percent predicted forced expiratory volume in 1 second from the prior 6-month baseline (5.8 vs. 3.6). Virus positivity was associated with reduced risk of future PEx (hazard ratio, 0.82; 95% confidence interval, 0.69-0.99; P = 0.034) and longer median time to next PEx (255 d vs. 172 d; P = 0.021) compared with virus negativity.Conclusions: More than one-third of STOP2 participants treated for a PEx had a positive test result for a respiratory virus with more symptomatic initial presentation compared with virus-negative participants, but favorable long-term outcomes. More refined phenotyping of PEx, taking VRIs into account, may aid in optimizing personalized management of PEx.Clinical trial registered with www.clinicaltrials.gov (NCT02781610).

Impact of Respiratory Viral Infections in Transplant Recipients

Respiratory viral infections (RVIs) are among the leading cause of morbidity and mortality in pediatric hematopoietic stem cell transplant (HCT) and solid organ transplant (SOT) recipients. Transplant recipients remain at high risk for super imposed bacterial and fungal pneumonia, chronic graft dysfunction, and graft failure as a result of RVIs. Recent multicenter retrospective studies and prospective studies utilizing contemporary molecular diagnostic techniques have better delineated the epidemiology and outcomes of RVIs in pediatric transplant recipients and have advanced the development of preventative vaccines and treatment interventions in this population. In this review, we will define the epidemiology and outcomes of RVIs in SOT and HSCT recipients, describe the available assays for diagnosing a suspected RVI, highlight evolving management and vaccination strategies, review the risk of donor derived RVI in SOT recipients, and discuss considerations for delaying transplantation in the presence of an RVI.

Congenital heart surgery outcomes in patients with positive respiratory viral swabs

OBJECTIVE

To examine whether or not viral positive patients experienced worse outcomes and assess differences in surgical outcomes between viral-positive patients with and without viral symptoms within 30 days of surgery.

METHODS

This retrospective study reviewed charts of pediatric patients who underwent congenital heart surgery and routine viral testing at a single institution over a consecutive 3-year period (2017-2019). Patients with a history of heart transplants, pacemaker changes, or implants, and mediastinal washouts were excluded from the study. Surgical outcomes were compared by viral status and viral symptoms, using the Fisher exact and Wilcoxon rank sum tests.

RESULTS

Among 1041 patients, 374 patients underwent routine preoperative viral testing, with 107 patients testing positive and 267 testing negative for viral swabs before surgery. There were no significant differences observed in surgical outcomes by viral status, including no differences in mortality. Among the 107 patients with positive viral swabs before surgery, comparisons between 24 patients with viral symptoms and 83 without symptoms within 30 days of surgery detected no significant differences in mortality or complication rates. However, symptomatic versus asymptomatic patients had significantly longer postoperative stay (23.4 vs 13.4 days; P = .02) and intubation time (9.8 vs 4.9 hours; P = .004).

CONCLUSIONS

Patients who test positive before congenital heart surgery and are asymptomatic beyond the incubation period may proceed to surgery with no further delay. Patients who are viral positive and symptomatic have a longer postoperative stay and intubation time. A prospective study is needed to assess the importance of routine viral testing.

Impact of RSV test positivity, patient characteristics, and treatment characteristics on the cost of hospitalization for acute bronchiolitis in a French university medical center (2010-2015)

Background

In young children, respiratory syncytial virus (RSV)-related bronchiolitis is typically more severe than other respiratory tract infections, with a greater need for oxygen therapy and respiratory support. Few studies have compared the cost of hospitalization with regard to virological status. The objective of this study was to compare the costs of hospitalization for RSV-positive vs. RSV-negative bronchiolitis in a French university medical center between 2010 and 2015.

Methods

The cost models were compared using conventional goodness-of-fit criteria. Covariates included the characteristics of the patients, pre-existing respiratory and non-respiratory comorbidities, superinfections, medical care provided, and the length of stay.

Results

RSV was detected in 679 (58.3%) of the 1,164 hospital stays by children under 2 years with virological data. Oxygen therapy and respiratory support were twice as frequent for the RSV-positive cases. The median hospitalization cost was estimated at €3,248.4 (interquartile range: €2,572.1). The cost distribution was positively skewed with a variation coefficient (CV = standard deviation/mean) greater than one (mean = €4,212.9, standard deviation = €5,047, CV = 1.2). In univariate analyses, there was no significant cost difference between the RSV-positive and RSV-negative cases. In the best multivariate model, the significant positive effect of RSV positivity on cost waned after the introduction of medical care variables and the length of stay. The results were sensitive to the specification of the model.

Conclusions

It was impossible to firmly conclude that hospitalization costs were higher for the RSV-positive cases.

Risk Factors for Respiratory Viral Infections: A Spotlight on Climate Change and Air Pollution

Climate change has both direct and indirect effects on human health, and some populations are more vulnerable to these effects than others. Viral respiratory infections are most common illnesses in humans, with estimated 17 billion incident infections globally in 2019. Anthropogenic drivers of climate change, chiefly the emission of greenhouse gases and toxic pollutants from burning of fossil fuels, and the consequential changes in temperature, precipitation, and frequency of extreme weather events have been linked with increased susceptibility to viral respiratory infections. Air pollutants like nitrogen dioxide, particulate matter, diesel exhaust particles, and ozone have been shown to impact susceptibility and immune responses to viral infections through various mechanisms, including exaggerated or impaired innate and adaptive immune responses, disruption of the airway epithelial barrier, altered cell surface receptor expression, and impaired cytotoxic function. An estimated 90% of the world's population is exposed to air pollution, making this a topic with high relevance to human health. This review summarizes the available epidemiologic and experimental evidence for an association between climate change, air pollution, and viral respiratory infection.

Type 2 cytokine genes as allergic asthma risk factors after viral bronchiolitis in early childhood

Background

Genome-wide association studies of asthma have identified associations with variants in type-2 related genes. Also, specific interactions between genetic variants and viral bronchiolitis in the development of asthma has been suggested.

Objective

To conduct a gene-based analysis of genetic variants in type 2 cytokine related genes as risk factors for allergic asthma at school age, and further, to study their interaction with specific viral infections in early childhood.

Methods

A prospectively investigated cohort of children with previous bronchiolitis and controls came for follow-up at school age. The research visit, blinded to viral exposure, included detailed lung function tests, laboratory investigation, and questionnaires. Allergic asthma was defined as typical symptoms plus objective variable airway obstruction, in addition to laboratory verified atopy (elevated eosinophil count or sensitization to an allergen). Targeted and complete sequencing was performed for nine type 2 cytokine candidate genes: IL4, 5, 13, 25, 33 and 37, IL17RB, CRLF2 and TSLP.

Results

At follow-up, there were 109 children with genetic data, 91 with a history of bronchiolitis (46% respiratory syncytial virus, 24% human rhinovirus, 15% human metapneumovirus and 14% mixed viral etiology) and 18 without. The median age was 9.4 years (range 6-13) and 41 (38%) had laboratory verified atopy. Twenty-one children (19%) met the definition of allergic asthma. After adjusting for age, sex and five viral categories, IL33 achieved nominal significance (p = 0.017) for a positive association with allergic asthma development. In the gene-virus interaction analysis, the variant set in IL17RB demonstrated a nominally significant positive interaction with human metapneumovirus infection (p=0.05).

Conclusion

The results highlight the multifactorial nature of allergic asthma risk, with both viral infection and inherited genetic variants contributing to increasing risk. Results for IL33 and IL17RB were nominally significant and are potential candidate targets for designing therapeutics and early screening, but these results must be replicated in an independent study.

A Versatile Biomimic Nanotemplating Fluidic Assay for Multiplex Quantitative Monitoring of Viral Respiratory Infections and Immune Responses in Saliva and Blood

The last pandemic exposed critical gaps in monitoring and mitigating the spread of viral respiratory infections at the point-of-need. A cost-effective multiplexed fluidic device (NFluidEX), as a home-test kit analogous to a glucometer, that uses saliva and blood for parallel quantitative detection of viral infection and body's immune response in an automated manner within 11 min is proposed. The technology integrates a versatile biomimetic receptor based on molecularly imprinted polymers in a core-shell structure with nano gold electrodes, a multiplexed fluidic-impedimetric readout, built-in saliva collection/preparation, and smartphone-enabled data acquisition and interpretation. NFluidEX is validated with Influenza A H1N1 and SARS-CoV-2 (original strain and variants of concern), and achieves low detection limit in saliva and blood for the viral proteins and the anti-receptor binding domain (RBD) Immunoglobulin G (IgG) and Immunoglobulin M (IgM), respectively. It is demonstrated that nanoprotrusions of gold electrodes are essential for the fine templating of antibodies and spike proteins during molecular imprinting, and differentiation of IgG and IgM in whole blood. In the clinical setting, NFluidEX achieves 100% sensitivity and 100% specificity by testing 44 COVID-positive and 25 COVID-negative saliva and blood samples on par with the real-time quantitative polymerase chain reaction (p < 0.001, 95% confidence) and the enzyme-linked immunosorbent assay.

Impact of a Rapid Respiratory Pathogen Panel on Antibiotic and Chest Radiography Usage and Hospital Length of Stay in the Pediatric Inpatient Setting

Introduction The objective of this study was to compare the antibiotic initiation rate and duration, hospital length of stay, emergency department (ED) admission rate and chest radiography usage in a pediatric inpatient unit before and after the decentralization of rapid respiratory pathogen panel (RRPP) processing. Methods This retrospective cohort study examined antibiotic initiation rates and durations, hospital lengths of stay, ED admission rates, and chest radiography usage from 2 respiratory virus seasons. For the 2014 cohort, RRPPs were processed at a centralized laboratory, and result times averaged 26 hours, whereas for the 2015 cohort, RRPPs were processed on-site with result times averaging 2 hours. Demographic data were collected and demonstrated similar populations. Chi-square testing was used to detect the change of antibiotic initiation rates, ED admission rates, and chest radiography usage after on-site RRPP processing was introduced. Antibiotic duration and hospital length of stay were determined by Wilcoxon rank sum. Results The study population included 94 patients from the 2014 respiratory virus season and 108 patients from the 2015 respiratory virus season. There were no statistically significant differences in gender, ethnicity, or age between the 2 cohorts. Antimicrobial initiation rates during hospital stay decreased from 46% to 27% (p = 0.005). The rate of admission from the ED decreased from 75% to 30% (p < 0.001). There were no statistically significant differences in antibiotic duration, hospital length of stay, or chest radiography usage. Conclusion Rapid respiratory pathogen testing is a useful tool that can decrease unnecessary antibiotic initiation and hospital admissions in the pediatric population.

Overnutrition, Nasopharyngeal Pathogenic Bacteria and Proinflammatory Cytokines in Infants with Viral Lower Respiratory Tract Infections

Background: Little is known about the interaction between the nasopharyngeal bacterial profile and the nutritional status in children. In this study, our main goal was to evaluate the associations between overnutrition and the presence of four potentially pathogenic bacteria in the nasopharynx of infants with viral lower respiratory tract infections (LRTI). In addition, we determined whether changes in the nasopharyngeal bacterial profile were associated with mucosal and serum proinflammatory cytokines and with clinical disease severity. Methods: We enrolled 116 children less than 2 years old hospitalized for viral LRTI during two consecutive respiratory seasons (May 2016 to August 2017); their nutritional status was assessed, and nasopharyngeal and blood samples were obtained. S. aureus, S. pneumoniae, H. influenzae, M. catarrhalis, and respiratory viruses were identified in nasopharyngeal samples by qPCR. Cytokine concentrations were measured in nasopharyngeal and blood samples. Disease severity was assessed by the length of hospitalization and oxygen therapy. Results: Nasopharyngeal pathogenic bacteria were identified in 96.6% of the enrolled children, and 80% of them tested positive for two or more bacteria. The presence and loads of M. catarrhalis was higher (p = 0.001 and p = 0.022, respectively) in children with overnutrition (n = 47) compared with those with normal weights (n = 69). In addition, the detection of >2 bacteria was more frequent in children with overnutrition compared to those with normal weight (p = 0.02). Multivariate regression models showed that the presence and loads of S. pneumoniae and M. catarrhalis were associated with higher concentrations of IL-6 in plasma and TNF-α in mucosal samples in children with overnutrition. Conclusions: The nasopharyngeal profile of young children with overnutrition was characterized by an over representation of pathogenic bacteria and proinflammatory cytokines.

Wearable sensor-based detection of influenza in presymptomatic and asymptomatic individuals

BACKGROUND

The COVID-19 pandemic highlighted the need for early detection of viral infections in symptomatic and asymptomatic individuals to allow for timely clinical management and public health interventions.

METHODS

Twenty healthy adults were challenged with an influenza A (H3N2) virus and prospectively monitored from 7 days before through 10 days after inoculation, using wearable electrocardiogram and physical activity sensors (Clinical Trial: NCT04204493; https://clinicaltrials.gov/ct2/show/NCT04204993). This framework allowed for responses to be accurately referenced to the infection event. For each participant, we trained a semi-supervised multivariable anomaly detection model on data acquired before inoculation and used it to classify the post-inoculation dataset.

RESULTS

Inoculation with this challenge virus was well-tolerated with an infection rate of 85%. With the model classification threshold set so that no alarms were recorded in the 170 healthy days recorded, the algorithm correctly identified 16 of 17 (94%) positive presymptomatic and asymptomatic individuals, on average 58 hours post inoculation and 23 hrs before the symptom onset.

CONCLUSION

The data processing and modeling methodology show promise for the early detection of respiratory illness. The detection algorithm is compatible with data collected from smartwatches using optical techniques but needs to be validated in large heterogeneous cohorts in normal living conditions.

A Review on the Antiviral Activity of Functional Foods Against COVID-19 and Viral Respiratory Tract Infections

Due to the absence of successful therapy, vaccines for protection are continuously being developed. Since vaccines must be thoroughly tested, viral respiratory tract infections (VRTIs), mainly coronaviruses, have seriously affected human health worldwide in recent years. In this review, we presented the relevant data which originated from trusted publishers regarding the practical benefits of functional foods (FFs) and their dietary sources, in addition to natural plant products, in viral respiratory and COVID-19 prevention and immune-boosting activities. As a result, FFs were confirmed to be functionally active ingredients for preventing COVID-19 and VRTIs. Furthermore, the antiviral activity and immunological effects of FFs against VRTIs and COVID-19 and their potential main mechanisms of action are also being reviewed. Therefore, to prevent COVID-19 and VRTIs, it is critical to identify controlling the activities and immune-enhancing functional food constituents as early as possible. We further aimed to summarize functional food constituents as a dietary supplement that aids in immune system boosting and may effectively reduce VRTIs and COVID-19 and promote therapeutic efficacy.

Overnutrition in Infants Is Associated With High Level of Leptin, Viral Coinfection and Increased Severity of Respiratory Infections: A Cross-Sectional Study

Objective: To investigate the relationship of overnutrition (obese and overweight) with severity of illness in children hospitalized with acute lower respiratory infections (ALRIs), frequency of viral coinfections and leptin levels. Methods: We studied 124 children <2 years old that were hospitalized for ALRI. Nutritional status was calculated by z-scores according to weight-for-age z-scores, length or height-for-age z-scores, and weight-for-height z-scores. Nasopharyngeal aspirates (NPAs) were obtained and viral respiratory pathogens were identified using reverse transcription polymerase chain reactions (RT-PCR). Respiratory syncytial virus (RSV) load was assessed using quantitative RT-PCR. NPA and plasma leptin level were measured. Clinical data and nutritional status were recorded, and patients were followed up until hospital discharge. Viral coinfection was defined as the presence of two or more viruses detected in the same respiratory sample. Severity of illness was determined by length of hospitalization and duration of oxygen therapy. Results: Children with overnutrition showed a greater frequency of viral coinfection than those with normal weight (71% obese vs. 37% normal weight p = 0.013; 68% overweight vs. 37% normal weight p = 0.004). A lower RSV load was found in obese (5.91 log₁₀ copies/mL) and overweight children (6.49 log₁₀ copies/mL) compared to normal weight children (8.06 log₁₀ copies/mL; p = 0.021 in both cases). In multivariate analysis, obese, and overweight infants <6 months old were associated with longer hospital stays (RR = 1.68; CI: 1.30-2.15 and obese: RR = 1.68; CI: 1.01-2.71, respectively) as well as a greater duration of oxygen therapy (RR = 1.80; IC: 1.41-2.29 and obese: RR = 1.91; CI: 1.15-3.15, respectively). Obese children <6 months showed higher plasma leptin level than normal weight children (7.58 vs. 5.12 ng/μl; p <0.046). Conclusions: In infants younger than 6 months, overnutrition condition was related to increased severity of infections and high plasma leptin level. Also, children with overnutrition showed a greater frequency of viral coinfection and low RSV viral load compared to normal weights children. These findings further contribute to the already existent evidence supporting the importance of overnutrition prevention in pediatric populations.

Human respiratory syncytial virus: prevalence, viral co-infections and risk factors for lower respiratory tract infections in children under 5 years of age at a general hospital in the Democratic Republic of Congo

PURPOSE

This study aimed to determine the prevalence of human respiratory syncytial virus (HRSV) acute respiratory infection (ARI) in children under the age of 5 years at the Provincial General Hospital of Bukavu (PGHB), and to analyse factors associated with the risk of ARI being diagnosed as lower respiratory tract infection (LRTI).

METHODOLOGY

A total of 146 children under 5 years visiting the PGHB for ARI between August and December 2016 were recruited, and socio-demographic information, clinical data and nasopharyngeal swabs were collected. The samples were analysed by a multiplex reverse transcriptase polymerase chain reaction targeting 15 different viruses.

RESULTS

Of 146 samples collected, 84 (57.5 %) displayed a positive result of at least one of the 15 viruses. The overall prevalence of HRSV was 21.2 %. HRSV A (30, 20.5 %) was the virus the most detected, followed by HRV (24, 16.4 %), PIV3 (20, 16.6) and ADV (7, 4.79 %). The other viruses were detected in three or fewer cases. There were only 11 (7.5 %) cases of co-infection. HRSV infection, malnutrition, younger age, rural settings, low income and mother illiteracy were associated with the risk of ARI being diagnosed as LRTI in bivariate analyses but, after adjusting for the confounding factors, only HRSV infection and younger age were independently associated with LRTI.

CONCLUSION

The prevalence of HRSV is high among children visiting the PGHB for ARI. HRSV infection and lower age are independently associated with the risk of ARI being diagnosed as LRTI.

Global Influenza Hospital-based Surveillance Network (GIHSN): results of surveillance of influenza and other respiratory viruses in hospitalised patients in Brazil, 2015

BACKGROUND

Influenza-like illness occurs annually worldwide, with peak timing and severity varying seasonally, resulting in significant annual mortality.

OBJECTIVES

There were three objectives: (1) to describe the epidemiological and clinical features of hospitalised patients with severe acute respiratory infection caused by influenza and other respiratory viruses (ORVs); (2) to report the influenza seasonality in the region and (3) to correlate findings of influenza circulation and immunisation time in Brazil.

PATIENTS/METHODS

This study took place in three Brazilian hospitals located in cities with different climatic conditions (Curitiba (south), Rio de Janeiro (south-east) and Fortaleza (north-east)). Patients presenting with an acute process with indication for admission consisting of a predefined set of conditions potentially associated with recent influenza infection were enrolled.

RESULTS

We screened 1666 patients, with 595 meeting the inclusion criteria. Influenza viruses and ORVs were detected in 6.5% and 59% of patients, respectively. Influenza-positive cases fell into the severe spectrum as compared with those with ORVs (30% vs 11%), but without any difference in mortality rates. Epidemiological results revealed variations in the peak time of influenza infections between north-east (Fortaleza) and south (Curitiba) Brazil, basically following the rain period of each region. In north-east Brazil, viral circulation was prevalent in the first 4 months of the year, indicating that the vaccination campaign occurred in a postseasonal period, possibly explaining the low effectiveness.

CONCLUSIONS

The active-surveillance model is a valuable tool for investigating respiratory virus impact on hospitalised patients, with influenza-infection monitoring enabling implementation of adequate preventive measures.

Viral Respiratory Infections in Preterm Infants during and after Hospitalization

OBJECTIVE

To determine the burden of viral respiratory infections in preterm infants both during and subsequent to neonatal intensive care unit (NICU) hospitalization and to compare this with term infants living in the community.

STUDY DESIGN

From March 2013 through March 2015, we enrolled 189 newborns (96 term and 93 preterm) into a prospective, longitudinal study obtaining nose/throat swabs within 7 days of birth, weekly while hospitalized and then monthly to 4 months after hospital discharge. Taqman array cards were used to identify 16 viral respiratory pathogens by real-time polymerase chain reaction. Demographic, clinical, and laboratory data were gathered from electronic medical records, and parent interview while hospitalized with interval histories collected at monthly visits. The hospital course of all preterm infants who underwent late-onset sepsis evaluations was reviewed.

RESULTS

Over 119 weeks, we collected 618 nose/throat swabs from at risk preterm infants in our level IV regional NICU. Only 4 infants had viral respiratory infections, all less than 28 weeks gestation at birth. Two infants were symptomatic with the infections recognized by the clinical team. The daily risk of acquiring a respiratory viral infection in preterm infants in the NICU was significantly lower than in the full term cohort living in the community. Once discharged from the hospital, viral respiratory infections were common in all infants.

CONCLUSIONS

Viral respiratory infections are infrequent in a NICU with strict infection prevention strategies and do not appear to cause unrecognized illness. Both preterm and term infants living in the community quickly acquire respiratory viral infections.

Viral Respiratory Infections of Adults in the Intensive Care Unit

Viral lower respiratory tract infections (LRTIs) are an underappreciated cause of critical illness in adults. Recent advances in viral detection techniques over the past decade have demonstrated viral LRTIs are associated with rates of morbidity, mortality, and health care utilization comparable to those of seen with bacterial community acquired and nosocomial pneumonias. In this review, we describe the relationship between viral LRTIs and critical illness, as well as discuss relevant clinical features and management strategies for the more prevalent respiratory viral pathogens.

Is virus coinfection a predictor of severity in children with viral respiratory infections?

Molecular assays have resulted in increased detection of viral respiratory infections, including virus coinfection, from children with acute respiratory infections. Yet the clinical severity of virus coinfection compared to single virus infection remains uncertain. We performed a retrospective study of children presenting with acute respiratory infections comparing clinical severity of single respiratory virus infection to virus coinfection, detected on midturbinate swabs by molecular assays. Patient characteristics and measures of clinical severity were abstracted from health records. A total of 472 virus-infected children were included, 391 with a single virus infection and 81 with virus coinfection. Virus status did not affect admission to hospital (odds ratio (OR) = 0.8; 95 % confidence interval (CI) 0.5–1.4; p 0.491) or clinical disease severity among inpatients (OR = 0.8; 95% CI 0.5–1.5; p 0.515) after adjusting for age and underlying comorbidities. However, children infected with rhinovirus/enterovirus (HRV/ENT) alone were more likely to be admitted to the hospital compared to those coinfected with HRV/ENT and at least another virus, although this was not significant in multivariable analyses (OR 0.47; 95% CI 0.22–1.0; p 0.051). In multivariable analyses, children coinfected with respiratory syncytial virus (RSV) and other viruses were significantly more likely to present with radiologically confirmed pneumonia compared to those with an isolated RSV infection (OR 3.16, 95% CI 1.07–9.34, p 0.037). Equivalent clinical severity was observed between children with single virus infection and virus coinfection, although children coinfected with RSV and other viruses presented more frequently with pneumonia than those with single RSV infection. Increased disease severity observed among children with single HRV/ENT infection requires further investigation.

The current epidemiology and clinical decisions surrounding acute respiratory infections

Acute respiratory infection (ARI) is a common diagnosis in outpatient and emergent care settings. Currently available diagnostics are limited, creating uncertainty in the use of antibacterial, antiviral, or supportive care. Up to 72% of ambulatory care patients with ARI are treated with an antibacterial, despite only a small fraction actually needing one. Antibiotic overuse is not restricted to ambulatory care: ARI accounts for approximately 5 million emergency department (ED) visits annually in the USA, where 52-61% of such patients receive antibiotics. Thus, an accurate test for the presence or absence of viral or bacterial infection is needed. In this review, we focus on recent research showing that the host-response (genomic, proteomic, or miRNA) can accomplish this task.

Severe complications in influenza-like illnesses

OBJECTIVE

Data on complications from upper respiratory infection are limited. We examined development of severe complications in children presenting to the emergency department (ED) for moderate to severe influenza-like illness (ILI).

METHODS

Prospective cohort study of children 0 to 19 years presenting to a tertiary care children's hospital ED during peak respiratory viral seasons from 2008 to 2010. Subjects included had moderate to severe ILI, defined by performance of venipuncture and nasopharyngeal multiplex polymerase chain reaction for respiratory viruses. Severe complications (respiratory failure, encephalopathy, seizures, pneumonia, bacteremia, death) were prospectively determined. Risk factors for severe complications were collected, including demographics, comorbidities, and household exposures.

RESULTS

There were 241 enrolled subjects with median age of 27.4 months (interquartile range 8.9-68.5); 59.3% were boys and 48.5% were black. High-risk conditions were present in 53.5%. Severe complications developed in 35.3% (95% confidence interval [CI] 29.3-41.3), most frequently pneumonia (26.1%). The risk for severe complications was increased in subjects with neurologic or neuromuscular conditions (relative risk 4.0; 95% CI 1.9-8.2). No specific respiratory virus was associated with development of severe complications. Among patients with influenza, severe complications were greater with subtype H1N1 infection (relative risk 1.45, 95% CI 0.99-2.13, P = .048), and were at highest risk for pneumonia (relative risk 4.2, 95% CI 1.2-15.9).

CONCLUSION

In children presenting to the ED for moderate to severe ILI, those with neurologic and neuromuscular disease are at increased risk for severe complications. Development of severe complications did not differ by infecting virus; however, risk of severe complications was greater with subtype H1N1 compared with other influenza.

Epidemiology of virus-induced wheezing/asthma in children

Wheezing is a lower respiratory tract symptom induced by various viral respiratory infections. Epidemiological studies have revealed the phenotypes of wheezing in early childhood which have different risk factors for the development of asthma among school age children. The major viral species causing wheezing in children include respiratory syncytial virus, rhinovirus, human metapneumovirus and influenza viruses. It has been shown that the impact on the development of asthma is different between those virus species. Moreover, recent studies have also focused on the interaction between virus infection and other risk factors in the development of asthma, such as genetic factors or allergic sensitization. In this review, we summarize the previous findings and discuss how clinicians can effectively intervene in these viral infections to prevent the development of asthma.

Clinical spectrum of acute otitis media complicating upper respiratory tract viral infection

BACKGROUND

acute otitis media (AOM) often occurs as a complication of upper respiratory tract infection (URI).

OBJECTIVE

to describe otoscopic findings during URI, the full clinical spectrum of AOM, and outcome of cases managed with watchful waiting.

METHODS

: In a prospective study of 294 healthy children (6 months-3 years), characteristics of AOM complicating URI were studied. Otoscopic findings were categorized by tympanic membrane (TM) position, color, translucency, and mobility. Otoscopic score was assigned based on McCormick otoscopy scale (OS)-8 scale.

RESULTS

during days 1 to 7 of URI, otoscopic findings at 1114 visits were consistent with AOM in 22%; myringitis (inflamed TM, no fluid) was diagnosed in 7%. In AOM episodes diagnosed within 28 days of URI onset, TM position was described as: nonbulging (19%), mild bulging (45%), bulging (29%), and TM perforation occurred in (6%). OS-8 scale showed mild TM inflammation (OS, 2-3) in 6%, moderate (OS, 4-5) in 59%, and severe (OS, 6-8) in 35%. In 54% of 126 bilateral AOM episodes, inflammation of both TMs was at different stages. Of 28 cases of nonsevere AOM managed with watchful waiting, 4 progressed and 3 later required an antibiotic.

CONCLUSIONS

AOM is a spectrum of infection that may present at various stages, even in the same child with bilateral disease. During URI, otoscopic changes are observed from the first day of onset. Understanding the wide clinical spectrum of AOM is needed to help with future clinical trial design and development of a scoring system to establish treatment criteria that will minimize antibiotic use.

Acute viral bronchiolitis in children- a very common condition with few therapeutic options

Acute viral bronchiolitis remains a cause of substantial morbidity and health care costs in young infants. It is the most common lower respiratory tract condition and most common reason for admission to hospital in infants. Many respiratory viruses have been associated with acute viral bronchiolitis although respiratory syncytial virus (RSV) remains the most frequently identified virus. Most infants have a mild self limiting illness while others have more severe illness and require hospital admission and some will need ventilatory support. Differences in innate immune function in response to the respiratory viral insult as well as differences in the geometry of the airways may explain some of the variability in clinical pattern. Young age and history of prematurity remain the most important risk factors although male gender, indigenous status, exposure to tobacco smoke, poor socioeconomic factors and associated co-morbidities such as chronic lung disease and congenital heart disease increase the risks of more severe illness. Supportive therapy remains the major treatment option as no specific treatments to date have been shown to provide clinically important benefits except for inhaled hypertonic saline. Prophylaxis of high risk infants with palivizumab should be considered although the cost effectiveness is still unclear. Many questions remain regarding optimal management approaches for infants requiring hospitalisation with bronchiolitis including use of nasogastric feeding, the optimal role of supplemental oxygen, optimal use of hypertonic saline and the role of combinations of therapies, the use of heliox or modern physiotherapy approaches.

Sinusitis in the common cold

BACKGROUND

Acute community-acquired sinusitis is considered a bacterial complication of the common cold. Radiologic abnormalities in sinuses occur, however, in most patients with upper respiratory virus infections.

OBJECTIVE

Assessment of the occurrence, clinical profile, laboratory findings, and outcome of radiologically confirmed sinusitis was carried out as part of a common cold study in young adults.

METHODS

Clinical examinations and radiography of the paranasal sinuses were carried out on days 1, 7, and 21 in 197 patients with the common cold. The symptoms were recorded on diary cards on days 1 to 20. Ten viruses and 5 bacteria were studied as etiologic agents of common cold as reported earlier. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and total white blood cell counts with differentials were determined in 40 randomized subjects on day 7. The effect of 6 days of intranasal fluticasone propionate treatment of the common cold in the prevention of sinusitis was analyzed.

RESULTS

On day 7, 39% of patients with the common cold in the placebo group (n = 98) had sinusitis, which we would prefer to call viral sinusitis. The symptoms of patients with sinusitis and those without it were not clinically distinguishable. Viral infection was detected in 81.6% of patients with sinusitis. No significantly increased levels of antibodies to bacteria were detected. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and white blood cell counts were low in patients with sinusitis. All patients made a clinical recovery within 21 days without antibiotic treatment. Fluticasone propionate treatment tended to prevent paranasal sinusitis, especially in rhinovirus-positive subjects.

CONCLUSION

Viral sinusitis frequently occurs in the early days of the common cold, but it is a self-limited illness. The sinuses should not be imaged in patients with the common cold if the signs and symptoms of illness gradually become less severe and no specific signs suggestive of bacterial sinusitis occur.