Severity of human rhinovirus infection in immunocompromised adults is similar to that of 2009 H1N1 influenza

Incidence and transmission associated with respiratory viruses in an acute care facility: An observational study

We estimated the extent of respiratory virus transmission over three pre-COVID-19 seasons. Of 16,273 assays, 22.9% (3,726) detected ≥1 respiratory virus. The frequency of putatively hospital-acquired infection ranged from 6.9% (influenza A/B) to 24.7% (adenovirus). The 176 clusters were most commonly associated with rhinovirus/enterovirus (70) and influenza A/B (62).

Are any specific respiratory viruses more severe than others in recipients of allogeneic stem cell transplantation? A focus on lower respiratory tract disease

In the general population, influenza virus, respiratory syncytial virus, and SARS-CoV-2 are considered the most severe community-acquired respiratory viruses (CARVs). However, allogeneic stem cell transplant (allo-SCT) recipients may also face severe courses from other CARVs. This retrospective study compared outcomes of various CARV lower respiratory tract diseases (LRTD) in 235 adult allo-SCT recipients, excluding co-infection episodes. We included 235 adults allo-SCT recipients experiencing 353 CARV LRTD consecutive episodes (130 rhinovirus, 63 respiratory syncytial virus, 43 influenza, 43 human parainfluenza virus, 23 human metapneumovirus, 19 Omicron SARS-CoV-2, 17 common coronavirus, 10 adenovirus and 5 human bocavirus) between December 2013 and June 2023. Day 100 overall survival ranged from 78% to 90% without significant differences among CARV types. Multivariable analysis of day 100 all-cause mortality identified corticosteroid use of >1 to <30 mg/d [Hazard ratio (HR) 2.45, p = 0.02) and ≥30 mg/d (HR 2.20, p = 0.015) along with absolute lymphocyte count <0.2 × 109/L (HR 5.82, p < 0.001) and number of CARV episodes as a continuous variable per one episode increase (HR 0.48, p = 0.001) as independent risk factors for all-cause mortality. Degree of immunosuppression, rather than intrinsic CARV virulence, has the most significant impact on mortality in allo-SCT recipients with CARV-LRTD.

Patterns and predictors of positive multiplex polymerase chain reaction respiratory panel among patients with acute respiratory infections in a single center in Lebanon

BACKGROUND

Infectious agents associated with community-acquired acute respiratory infections (ARIs) remain understudied in Lebanon. We aim to assess the microbiological profiles of ARIs by employing polymerase chain reaction (PCR) and identifying predictors of positive PCR results among patients admitted for ARI.

METHODS AND RESULTS

We conducted a retrospective single-center study at the American University of Beirut Medical Center, including all respiratory PCR panels performed on pediatric (< 18) and adult (≥ 18) patients presenting with an ARI from January 2015 to March 2018, prior to the onset of the COVID-19 pandemic. We aimed to identify the epidemiological patterns of ARIs and the factors associated with positive PCRs in both adult and pediatric patients. Among 281 respiratory PCRs, 168 (59.7%) were positive for at least one pathogen, with 54.1% positive PCR for viruses, 7.8% for bacteria species, and 3.9% with virus-bacteria codetection. Almost 60% of the patients received antibiotics prior to PCR testing. PCR panels yielded more positive results in pediatric patients than in adults (P = 0.005). Bacterial detection was more common in adults compared to pediatrics (P < 0.001). The most common organism recovered in the entire population was Human Rhinovirus (RhV) (18.5%). Patients with pleural effusion on chest CT were less likely to have a positive PCR (95% Cl: 0.22-0.99). On multivariate analysis, pediatric age group (P < 0.001), stem cell transplant (P = 0.006), fever (P = 0.03) and UTRI symptoms (P = 0.004) were all predictive of a positive viral PCR.

CONCLUSION

Understanding the local epidemiology of ARI is crucial for proper antimicrobial stewardship. The identification of factors associated with positive respiratory PCR enhances our understanding of clinical characteristics and potential predictors of viral detection in our population.

Respiratory virus infections after allogeneic stem cell transplantation: Current understanding, knowledge gaps, and recent advances

Before the COVID-19 pandemic, common community-acquired seasonal respiratory viruses (CARVs) were a significant threat to the health and well-being of allogeneic hematopoietic cell transplant (allo-HCT) recipients, often resulting in severe illness and even death. The pandemic has further highlighted the significant risk that immunosuppressed patients, including allo-HCT recipients, face when infected with SARS-CoV-2. As preventive transmission measures are relaxed and CARVs circulate again among the community, including in allo-HSCT recipients, it is crucial to understand the current state of knowledge, gaps, and recent advances regarding CARV infection in allo-HCT recipients. Urgent research is needed to identify seasonal respiratory viruses as potential drivers for future pandemics.

Characteristics, Management, and Outcomes of Community-Acquired Pneumonia Due to Human Rhinovirus-A Retrospective Study

INTRODUCTION

Human rhinovirus (HRV) can lead to a variety of respiratory illnesses; it is also an uncommon cause of community-acquired pneumonia (CAP). We described the characteristics and outcomes of patients hospitalized for CAP due to HRV.

METHODS

We retrospectively studied consecutive adult patients admitted to King Abdulaziz Medical City-Riyadh with CAP due to HRV between 2016 and 2019. The diagnosis was made by respiratory multiplex PCR within 48 hours of hospitalization. We compared patients requiring ICU admission to those who did not.

RESULTS

One-hundred-and-six patients were studied (peak hospitalization between November and January, median age 71.5 years, hypertension 59%, diabetes 50%, and chronic respiratory disease 44.3%); 16 (15.1%) patients required ICU admission. The median pneumonia severity index score (PSI) was 107, with no significant difference between ICU and nonICU patients. ICU patients had a higher prevalence of tachypnea (62.5% vs. 26.7%, p=0.005), hemoptysis (12.5% vs 0%, p=0.001), and lymphopenia (71.4% vs 26.3%, p=0.01). Chest X-ray on presentation showed bilateral infiltrates in 47/101 (46.5%) patients and unilateral infiltrates in 26/101 (25.7%) patients. Systemic corticosteroids were used in 54.7% of patients (the median initial dose was 120 mg of prednisone equivalent and was higher in nonICU patients). Most (69.2%) ICU patients received mechanical ventilation (median duration of 8 days). Bacterial coinfection (6.6%) and superinfection (3.8%) were rare. The overall hospital mortality was 9.4% (higher for ICU patients: 37.5% vs. 4.4%, p < 0.001).

CONCLUSIONS

Most patients with CAP due to HRV were elderly and had significant comorbidities. ICU admission was required in almost one in six patients and was associated with higher mortality.

COVID-19 Shuts Doors to Flu but Keeps Them Open to Rhinoviruses

Simple Summary

Ten years have passed since the beginning of the H1N1pdm09 flu pandemic. No sooner had humanity recovered from its consequences than a new attack came—the COVID-19 pandemic. What happens to other respiratory infectious diseases during a global disaster such as the COVID-19 pandemic? The pandemic brought about by the novel SARS-CoV-2 virus has disrupted many well-established epidemiological and pathogenetic relationships, as well as mechanisms affecting infections with other respiratory viruses. The level of circulation of many respiratory pathogens has changed significantly. For instance, global influenza activity is at much lower levels than expected. In many regions, the influenza season has not started. Intriguingly, the COVID-19 pandemic did not substantially affect the spread of human rhinoviruses. In this review, the main properties of epidemiologically significant respiratory viruses such as SARS-CoV-2, influenza virus, and human rhinovirus are described.

Abstract

It is well known that rhinoviruses are distributed across the globe and are the most common cause of the common cold in all age groups. Rhinoviruses are widely considered to be harmless because they are generally perceived as respiratory viruses only capable of causing mild disease. However, they may also infect the lower respiratory tract, inducing chronic obstructive pulmonary disease and exacerbations of asthma, bronchiolitis, etc. The role of rhinoviruses in pathogenesis and the epidemiological process is underestimated, and they need to be intensively studied. In the light of recent data, it is now known that rhinoviruses could be one of the key epidemiological barriers that may influence the spread of influenza and novel coronaviruses. It has been reported that endemic human rhinoviruses delayed the development of the H1N1pdm09 influenza pandemic through viral interference. Moreover, human rhinoviruses have been suggested to block SARS-CoV-2 replication in the airways by triggering an interferon response. In this review, we summarized the main biological characteristics of genetically distinct viruses such as rhinoviruses, influenza viruses, and SARS-CoV-2 in an attempt to illuminate their main discrepancies and similarities. We hope that this comparative analysis will help us to better understand in which direction research in this area should move.

Characteristics of viral pneumonia in the COVID-19 era: an update

Influenza virus, rhinovirus, and adenovirus frequently cause viral pneumonia, an important cause of morbidity and mortality especially in the extreme ages of life. During the last two decades, three outbreaks of coronavirus-associated pneumonia, namely Severe Acute Respiratory Syndrome, Middle-East Respiratory Syndrome, and the ongoing Coronavirus Infectious Disease—2019 (COVID-19) were reported. The rate of diagnosis of viral pneumonia is increasingly approaching 60% among children identified as having community-acquired pneumonia (CAP). Clinical presentation ranges from mild to severe pneumonitis complicated by respiratory failure in severe cases. The most vulnerable patients, the elderly and those living with cancer, report a relevant mortality rate. No clinical characteristics can be useful to conclusively distinguish the different etiology of viral pneumonia. However, accessory symptoms, such as anosmia or ageusia together with respiratory symptoms suggest COVID-19. An etiologic-based treatment of viral pneumonia is possible in a small percentage of cases only. Neuraminidase inhibitors have been proven to reduce the need for ventilatory support and mortality rate while only a few data support the large-scale use of other antivirals. A low-middle dose of dexamethasone and heparin seems to be effective in COVID-19 patients, but data regarding their possible efficacy in viral pneumonia caused by other viruses are conflicting. In conclusion, viral pneumonia is a relevant cause of CAP, whose interest is increasing due to the current COVID-19 outbreak. To set up a therapeutic approach is difficult because of the low number of active molecules and the conflicting data bearing supportive treatments such as steroids.

Added Diagnostic Utility of Clinical Metagenomics for the Diagnosis of Pneumonia in Immunocompromised Adults

BACKGROUND

In the evaluation of community-acquired pneumonia, 30% to 60% of cases remain undiagnosed, despite extensive conventional microbiologic testing (CMT). Clinical metagenomics (CM) is an unbiased pathogen detection method that can increase diagnostic yield.

RESEARCH QUESTION

Does adding clinical metagenomics to conventional microbiologic testing improve the diagnostic yield for pneumonia in immunocompromised adults?

STUDY DESIGN AND METHODS

We performed a noninterventional prospective study of immunocompromised adults with pneumonia who underwent bronchoscopy and BAL over 2 years. CMT was performed per standard of care. A commercial CM test was performed on residual BAL fluid. Final microbiologic diagnoses were based on CMT vs CMT + CM. Final clinical diagnoses for CMT and CMT + CM were made based on laboratory results in conjunction with clinical and radiologic findings. Hypothetical impact of CMT + CM on management and antimicrobial stewardship was also assessed.

RESULTS

A total of 30 immunocompromised adult patients (31 episodes of pneumonia) were included. Final microbiologic diagnoses were made in 11 cases (35%) with the use of CMT and in 18 cases (58%) with the use of CMT + CM. Bacterial pneumonia was diagnosed in five cases (16%) by CMT and in 13 cases (42%) by CMT + CM; fungal pneumonia was diagnosed in six cases (19%) by CMT and in seven cases (23%) by CMT + CM, and viral pneumonia was diagnosed in two cases (6%) by CMT and in five cases (16%) by CMT + CM. The hypothetical impact of CMT + CM on management was deemed probable in one case, possible in eight cases, and unlikely in two cases, whereas the impact on antimicrobial stewardship was possible in 13 cases and unlikely in seven cases. Final clinical diagnoses were made in 20 of 31 cases (65%) based on CMT and in 23 of 31 cases (74%) based on CMT + CM.

INTERPRETATION

CMT + CM increased diagnostic yield in immunocompromised adults with pneumonia from 35% to 58%, mostly by the detection of additional bacterial causes but was less useful for fungal pneumonia.

Post-pandemic influenza A/H1N1pdm09 is associated with more severe outcomes than A/H3N2 and other respiratory viruses in adult hospitalisations

This study compares the frequency and severity of influenza A/H1N1pdm09 (A/H1), influenza A/H3N2 (A/H3) and other respiratory virus infections in hospitalised patients. Data from 17 332 adult hospitalised patients admitted to Sir Charles Gairdner Hospital, Perth, Western Australia, with a respiratory illness between 2012 and 2015 were linked with data containing reverse transcription polymerase chain reaction results for respiratory viruses including A/H1, A/H3, influenza B, human metapneumovirus, respiratory syncytial virus and parainfluenza. Of these, 1753 (10.1%) had test results. Multivariable regression analyses were conducted to compare the viruses for clinical outcomes including ICU admission, ventilation, pneumonia, length of stay and death. Patients with A/H1 were more likely to experience severe outcomes such as ICU admission (OR 2.5, 95% CI 1.2–5.5, P = 0.016), pneumonia (OR 3.0, 95% CI 1.6–5.7, P < 0.001) and lower risk of discharge from hospital (indicating longer lengths of hospitalisation; HR 0.64 95% CI 0.47–0.88, P = 0.005), than patients with A/H3. Patients with a non-influenza respiratory virus were less likely to experience severe clinical outcomes than patients with A/H1, however, had similar likelihood when compared to patients with A/H3. Patients hospitalised with A/H1 had higher odds of severe outcomes than patients with A/H3 or other respiratory viruses. Knowledge of circulating influenza strains is important for healthcare preparedness.

Viral Diagnostics

This chapter discusses recent developments in diagnostics for cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK virus (BKV), community respiratory viruses (CRVs), parvovirus, hepatitis viruses, HIV, and other viral agents of importance in solid organ and hematopoietic stem cell transplantation.

Structure-Based Drug Design of Potent Pyrazole Derivatives against Rhinovirus Replication

Rhinoviruses (RVs) have been linked to exacerbations of many pulmonary diseases, thus increasing morbidity and/or mortality in subjects at risk. Unfortunately, the wide variety of RV genotypes constitutes a major hindrance for the development of Rhinovirus replication inhibitors. In the current investigation, we have developed a novel series of pyrazole derivatives that potently inhibit the Rhinovirus replication. Compounds 10e and 10h behave as early stage inhibitors of Rhinovirus infection with a broad-spectrum activity against RV-A and RV-B species (EC₅₀ < 0.1 μM). We also evaluate the dynamics of the emerging resistance of these promising compounds and their in vitro genotoxicity. Molecular docking experiments shed light on the pharmacophoric elements interacting with residues of the drug-binding pocket.

Initial High Viral Load Is Associated with Prolonged Shedding of Human Rhinovirus in Allogeneic Hematopoietic Cell Transplant Recipients

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We examined prolonged shedding of rhinovirus after stem cell transplantation.

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The median shedding duration of rhinovirus was similar between species.

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Initial high viral load was a risk factor for prolonged shedding of rhinovirus.

Recent data suggest human rhinovirus (HRV) is associated with lower respiratory tract infection and mortality in hematopoietic cell transplant (HCT) recipients. Examining risk factors for prolonged viral shedding may provide critical insight for the development of novel therapeutics and help inform infection prevention practices. Our objective was to identify risk factors for prolonged shedding of HRV post-HCT. We prospectively collected weekly nasal samples from allogeneic HCT recipients from day 0 to day 100 post-transplant, and performed real-time reverse transcriptase PCR (December 2005 to February 2010). Subjects with symptomatic HRV infection and a negative test within 2 weeks of the last positive were included. Duration of shedding was defined as time between the first positive and first negative samples. Cycle threshold (Ct) values were used as a proxy for viral load. HRV species were identified by sequencing the 5′ noncoding region. Logistic regression analyses were performed to evaluate factors associated with prolonged shedding (≥21 days). We identified 38 HCT recipients with HRV infection fulfilling study criteria (32 adults, 6 children). Median duration of shedding was 9.5 days (range, 2 to 89 days); 18 patients had prolonged shedding. Among 26 samples sequenced, 69% were species A, and species B and C accounted for 15% each; the median shedding duration of HRV did not differ among species (P = .17). Bivariable logistic regression analyses suggest that initial high viral load (low Ct value) is associated with prolonged shedding. HCT recipients with initial high viral loads are at risk for prolonged HRV viral shedding.

Rhinovirus respiratory tract infection in hospitalized adult patients is associated with TH2 response irrespective of asthma

OBJECTIVES

We assessed the immunological response of hospitalized adult patients with rhinovirus infection, including critically-ill patients.

METHODS

The differential white blood cell (WBC) count and the levels of 29 plasma cytokines/chemokines were compared between 50 adult hospitalized patients with rhinovirus infection and 100 age-matched controls with influenza virus infection.

RESULTS

The demographics and comorbidities were similar between rhinovirus and influenza patients, but severe disease was more common for the rhinovirus cohort. Rhinovirus patients had significantly higher WBC counts than influenza patients, especially for eosinophil (P = 3.1 × 10^-8). The level of the T_H2 cytokine IL-5 was significantly higher among rhinovirus patients, while the levels of 9 other cytokines/chemokines were significantly lower among rhinovirus patients. The levels of CXCL-10 (IP-10), CCL-2 (MCP-1), IFN-α2, IFN-γ, IL-10, and IL-15 remained significantly lower among rhinovirus patients after correction for multiple comparisons. Notably, CXCL-10 had the highest area under the receiver operating characteristic curve (AUC) in differentiating rhinovirus from influenza patients (AUC, 0.918). In the patient subgroup without asthma, the difference in the WBC count and cytokine/chemokine levels between rhinovirus and influenza patients remained statistically significant.

CONCLUSIONS

Rhinovirus infection was characterized by a prominent T_H2 response, even in patients without asthma. CXCL-10 (IP-10) is a potential biomarker in differentiating rhinovirus from influenza infection.

Rhinovirus viremia in adult patients with high viral load in bronchoalveolar lavages

BACKGROUND

In children, rhinovirus viremia has been associated with higher nasopharyngeal loads and increase in severity of clinical signs and symptoms.

OBJECTIVES

This study aims to detect rhinovirus viremia in adult patients and to establish potential correlations with the clinical course.

STUDY DESIGN

Adult patients with rhinovirus strongly positive bronchoalveolar lavages (BAL, quantitation cycle, Cq values <25) detected between 2008 and 2014 were studied retrospectively. Blood sampled between two weeks before and two weeks after BAL sampling was tested for rhinovirus RNA. Underlying conditions, symptoms, radiography, microbiological data, and disease outcome were analysed.

RESULTS

Twenty-seven of 43 patients with rhinovirus positive BAL at Cq values <25 had blood samples available within the prespecified time-frame (mean blood 3-4 samples per patient). Four of these 27 patients (15%) tested rhinovirus RNA positive in their blood (of whom one patient twice). Genotyping demonstrated rhinovirus A01, A24, B52 and B92 in these four immunocompromised patients. Viremic patients were not significantly different with regard to underlying conditions, respiratory symptoms, radiological findings, co-pathogens nor the number of blood samples tested for RV. However, patients with rhinovirus viremia had significant higher mortality rates compared to patients without viremia, as all four died as a consequence of respiratory problems (100%) versus 22% (5/23), p=0.007 (Fisher's exact).

CONCLUSIONS

Rhinovirus viremia can occur in adult patients with a high viral load in BAL fluid. Rhinovirus viremia may be considered a negative prognostic factor, although a causative role with regard to the adverse outcome has yet to be demonstrated.

Immunization with Live Human Rhinovirus (HRV) 16 Induces Protection in Cotton Rats against HRV14 Infection

Human rhinoviruses (HRVs) are the main cause of cold-like illnesses, and currently no vaccine or antiviral therapies against HRVs are available to prevent or mitigate HRV infection. There are more than 150 antigenically heterogeneous HRV serotypes, with ∼90 HRVs belonging to major group species A and B. Development of small animal models that are susceptible to infection with major group HRVs would be beneficial for vaccine research. Previously, we showed that the cotton rat (Sigmodon hispidus) is semi-permissive to HRV16 (major group, species HRV-A virus) infection, replicating in the upper and lower respiratory tracts with measurable pathology, mucus production, and expression of inflammatory mediators. Herein, we report that intranasal infection of cotton rats with HRV14 (major group, species HRV-B virus) results in isolation of infectious virus from the nose and lung. Similar to HRV16, intramuscular immunization with live HRV14 induces homologous protection that correlated with high levels of serum neutralizing antibodies. Vaccination and challenge experiments with HRV14 and HRV16 to evaluate the development of cross-protective immunity demonstrate that intramuscular immunization with live HRV16 significantly protects animals against HRV14 challenge. Determination of the immunological mechanisms involved in heterologous protection and further characterization of infection with other major HRV serotypes in the cotton rat could enhance the robustness of the model to define heterotypic relationships between this diverse group of viruses and thereby increase its potential for development of a multi-serotype HRV vaccine.

Antiviral therapy for respiratory viral infections in immunocompromised patients

INTRODUCTION

Respiratory viruses (influenza, parainfluenza, respiratory syncytial virus, coronavirus, human metapneumovirus, and rhinovirus) represent the most common causes of respiratory viral infections in immunocompromised patients. Also, these infections may be more severe in immunocompromised patients than in the general population. Early diagnosis and treatment of viral infections continue to be of paramount importance in immunocompromised patients; because once viral replication and invasive infections are evident, prognosis can be grave. Areas covered: The purpose of this review is to provide an overview of the main antiviral agents used for the treatment of respiratory viral infections in immunocompromised patients and review of the new agents in the pipeline. Expert commentary: Over the past decade, important diagnostic advances, specifically, the use of rapid molecular testing has helped close the gap between clinical scenarios and pathogen identification and enhanced early diagnosis of viral infections and understanding of the role of prolonged shedding and viral loads. Advancements in novel antiviral therapeutics with high resistance thresholds and effective immunization for preventable infections in immunocompromised patients are needed.

Human rhinovirus detection in the lower respiratory tract of hematopoietic cell transplant recipients: association with mortality

Human rhinoviruses are the most common respiratory viruses detected in patients after hematopoietic cell transplantation. Although rhinovirus appears to occasionally cause severe lower respiratory tract infection in immunocompromised patients, the clinical significance of rhinovirus detection in the lower respiratory tract remains unknown. We evaluated 697 recipients transplanted between 1993 and 2015 with rhinovirus in respiratory samples. As comparative cohorts, 273 recipients with lower respiratory tract infection caused by respiratory syncytial virus (N=117), parainfluenza virus (N=120), or influenza (N=36) were analyzed. Factors associated with mortality were analyzed using Cox proportional hazard models. Among 569 subjects with rhinovirus upper respiratory tract infection and 128 subjects with rhinovirus lower respiratory tract infection, probabilities of overall mortality at 90 days were 6% and 41%, respectively (P<0.001). The survival rate after lower respiratory tract infection was not affected by the presence of co-pathogens (55% in patients with co-pathogens, 64% in patients without, P=0.34). Low monocyte count (P=0.027), oxygen use (P=0.015), and steroid dose greater than 1 mg/kg/day (P=0.003) before diagnosis were significantly associated with mortality among patients with lower respiratory tract infection in multivariable analysis. Mortality after rhinovirus lower respiratory tract infection was similar to that after lower respiratory tract infection by respiratory syncytial virus, parainfluenza virus or influenza in an adjusted model. In summary, transplant recipients with rhinovirus detection in the lower respiratory tract had high mortality rates comparable to viral pneumonia associated with other well-established respiratory viruses. Our data suggest rhinovirus can contribute to severe pulmonary disease in immunocompromised hosts.

Update on Human Rhinovirus and Coronavirus Infections

Human rhinovirus (HRV) and coronavirus (HCoV) infections are associated with both upper respiratory tract illness (“the common cold”) and lower respiratory tract illness (pneumonia). New species of HRVs and HCoVs have been diagnosed in the past decade. More sensitive diagnostic tests such as reverse transcription-polymerase chain reaction have expanded our understanding of the role these viruses play in both immunocompetent and immunosuppressed hosts. Recent identification of severe acute respiratory syndrome and Middle East respiratory syndrome viruses causing serious respiratory illnesses has led to renewed efforts for vaccine development. The role these viruses play in patients with chronic lung disease such as asthma makes the search for antiviral agents of increased importance.

Pulmonary and extrapulmonary complications of human rhinovirus infection in critically ill patients

BACKGROUND

Human rhinovirus (HRV) is frequently detected in patients with respiratory tract infection. However, the full clinical spectrum of HRV infection in critically ill patients is not well characterized.

OBJECTIVE

To evaluate the clinical and virological characteristics of critically ill patients with HRV infection.

STUDY DESIGN

HRV-specific reverse transcription-polymerase chain reaction (RT-PCR) was performed on nasopharyngeal aspirate (NPA) specimens from 294 adult patients who required admission into the intensive care unit (ICU). Clinical characteristics were analyzed. HRV genotyping using the 5'UTR-VP4-VP2 region was performed.

RESULTS

HRV was detected in NPA specimens of 22 patients (7.5%) by RT-PCR. Dyspnea was the most common presenting symptom (16/22; 72.7%), but seizure also occurred in 5 (22.7%) patients. Exacerbation of underlying disease occurred in 12 (54.5%) patients. Four (18.2%) patients died, and HRV was considered to play a role as the cause of death in 3 patients. Thirteen (59.1%) patients had pneumonia, and the most common radiological finding was consolidation (6/13; 46.2%). Streptococcus pneumoniae was the most common co-pathogen among patients with pneumonia. Among the 9 patients without pneumonia, 3 patients had exacerbation of underlying lung diseases, 3 patients had acute pulmonary edema, 2 patients with diabetes mellitus had acute complications from poor glycemic control, and 1 patient had status epilepticus. HRV-A was the most common species (64.3%), but there was no clear relationship between HRV species and clinical presentation.

CONCLUSION

Both pulmonary and extrapulmonary complications of HRV were common in critically ill patients.

Rhinovirus, Coronavirus, Enterovirus, and Bocavirus After Hematopoietic Cell Transplantation or Solid Organ Transplantation

Respiratory viral infections represent a significant cause of morbidity and mortality in immunocompromised hosts. Newer molecular detection assays have allowed for the characterization of several respiratory viruses not previously recognized as having significant clinical impact in the immunocompromised population. Human rhinoviruses are the most common respiratory viruses detected in the upper respiratory tract of hematopoietic cell transplant and lung transplant recipients, and evidence on the impact on clinical outcomes is mounting. Other respiratory viruses including enteroviruses (EVs), coronaviruses (CoVs), and bocavirus may also contribute to pulmonary disease; however, data is limited in the immunocompromised population. Further studies are needed to define the epidemiology, risk factors, and clinical outcomes of these infections; this data will help inform decisions regarding development of antiviral therapy and infection prevention strategies.

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.

Clinical outcomes associated with respiratory virus detection before allogeneic hematopoietic stem cell transplant

BACKGROUND

The management of respiratory virus infections prior to hematopoietic cell transplant (HCT) is difficult. We examined whether respiratory virus detection before HCT influenced the requirement for bronchoscopy, hospitalization, and overall survival following HCT.

METHODS

Pre-HCT and weekly post-HCT nasal washes were collected through day 100 from patients with and without symptoms. Samples were tested by multiplex polymerase chain reaction for respiratory syncytial virus, parainfluenza viruses 1-4, influenza A and B, human metapneumovirus, adenovirus, and human rhinoviruses, coronaviruses, and bocavirus.

RESULTS

Of 458 patients, 116 (25%) had respiratory viruses detected pre-HCT. Overall, patients with viruses detected pre-HCT had fewer days alive and out of the hospital and lower survival at day 100 (adjusted hazard ratio [aHR], 2.4; 95% confidence interval [CI], 1.3-4.5; P = .007) than patients with negative samples; this risk was also present with rhinovirus alone (aHR for mortality, 2.6; 95% CI, 1.2-5.5; P = .01). No difference in bronchoscopy incidence was seen in patients with and without respiratory viruses (aHR, 1.3; 95% CI, .8-2.0; P = .32). In symptomatic patients, those with respiratory viruses detected had increased overall mortality compared with patients without viruses detected (unadjusted HR, 3.5; 95% CI, 1.0-12.1; P = .05); among asymptomatic patients, detection of respiratory viruses was not associated with increased mortality.

CONCLUSIONS

These data support routine testing for respiratory viruses among symptomatic patients before HCT, and delay of transplant with virus detection when feasible, even for detection of rhinovirus alone. Further study is needed to address whether asymptomatic patients should undergo screening for respiratory virus detection before HCT.

Severity of rhinovirus infection in hospitalized adults is unrelated to genotype

Objectives

To determine whether rhinovirus (RV) species is associated with more severe clinical illness in adults.

Methods

Seventy-two RV-positive viral respiratory samples from adult patients were sequenced and analyzed phylogenetically after reverse transcriptase polymerase chain reaction of the region spanning the VP4 gene and 5′ terminus of the VP2 gene. The clinical features and severity of illness associated with the different RV species were compared.

Results

Phylogenetic analysis identified three distinct clusters as RV-A (54%), B (11%), or C (35%) species. In an unadjusted model, patients with RV-B infection were significantly more likely to have the composite outcome variable of death or intensive care unit admission (P = .03), but this effect diminished when controlling for patient sex. A logistic model of the relationship between RV species and adverse outcomes produced nonsignificant odds ratios when controlling for patient sex.

Conclusions

Infection with RV-A or RV-B was associated with greater severity of illness in our adult population; however, the association disappeared after controlling for confounders.

The FilmArray® respiratory panel: an automated, broadly multiplexed molecular test for the rapid and accurate detection of respiratory pathogens

The FilmArray Respiratory Panel (RP) (BioFire(™) Diagnostics, Inc., Salt Lake City, UT, USA) is the first multiplex molecular panel cleared by the US FDA for the detection of both bacterial and viral respiratory pathogens in nasopharygeal swabs. The FilmArray RP targets 20 pathogens including 17 viruses and subtypes and three bacteria, and is performed with minimal sample manipulation. The FilmArray RP has a fully automated sample-to-answer workflow with a turn-around-time of approximately 1 h. The reported sensitivity and specificity of the assay ranges from 80 to 100 and 100%, respectively, with the sensitivity for the adenovirus as low as 46%. A new version of the FilmArray RP assay (version 1.7) with improved sensitivity for the adenovirus was released in 2013. The performance characteristics and simplified workflow have allowed its implementation in a wide range of laboratories. The FilmArray RP has changed the diagnostic landscape and will have a significant impact on the care of patients with respiratory tract infection.

The common cold: potential for future prevention or cure

The common cold is the most frequent, although generally mild, human disease. Human Rhinoviruses are the prevalent causative agents, but other viruses are also implicated. Being so common, viral colds, have significant implications on public health and quality of life, but may also be life-threatening for vulnerable groups of patients. Specific diagnosis and treatment of the common cold still remain unmet needs. Molecular diagnostic techniques allow specific detection of known pathogens as well as the identification of newly emerging viruses. Although a number of medications or natural treatments have been shown to have some effect, either on the number or on the severity of common colds, no single agent is considerably effective. Virus-specific management remains in most cases a challenging potential as many factors have to be taken into account, including the diversity of the viral genomes, the heterogeneity of affected individuals, as well as the complexity of this long standing host-virus relationship.

Human rhinoviruses and severe respiratory infections: is it possible to identify at-risk patients early?

Molecular methods of viral screening have demonstrated that human rhinoviruses (HRVs) are associated with lower respiratory tract infections (LRTIs, including bronchiolitis and pneumonia), exacerbations of chronic pulmonary disease and the development of asthma. Patients with severe chronic diseases are at greater risk of developing major clinical problems when infected by HRVs, particularly if they are immunocompromised or have a chronic lung disease. Analysing the characteristics of HRVs does not provide any certainty concerning the risk of a poor prognosis and, although viremia seems to be associated with an increased risk of severe HRV infection, the available data are too scanty to be considered conclusive. However, a chest x-ray showing alveolar involvement suggests the potentially negative evolution of a bacterial superinfection. There is therefore an urgent need for more effective diagnostic, preventive and therapeutic measures in order to prevent HRV infection, and identify and treat the patients at highest risk.

Analysis of a potential cluster of rhinovirus infections in patients and staff on two haemato-oncology wards

BACKGROUND

Human rhinoviruses (HRV) cause the common cold, increased mortality in patients attending elderly care facilities and significant morbidity as well as mortality in the post-transplantation setting.

OBJECTIVES

The aim of the study was to determine if there had been a breakdown in infection control practice in a large haemato-oncology centre. Molecular techniques had detected increased numbers of HRV in respiratory samples from patients and staff over a 6-week period. Typing was performed to investigate the possibility of transmission between individuals.

STUDY DESIGN

This was a retrospective study having detected HRV RNA in combined nose and throat swab samples that were collected from 13 individuals: 8 patients and 5 staff members, in the haemato-oncology wards of a tertiary referral centre in January and February 2011. The 5'NTR and the VP4/VP2 region were used for HRV typing.

RESULTS

All 3 HRV species were detected with 7 HRV-A, 1 HRV-B, 4 HRV-C and 1 untyped. None of the individuals were infected by the same HRV serotype. Three individuals had multiple samples collected: 1 patient had an HRV-B infection over a 4-week period, 1 patient had an HRV-A infection over 3 months and 1 staff member had an HRV-C infection over 1 week, each shedding an unchanged serotype throughout the whole period.

CONCLUSION

Nucleotide sequence analysis confirmed that there was no breakdown in infection control measures. No transmission incidents had occurred between patients and/or between staff and patients.

Respiratory viral infections among hospitalized adults: experience of a single tertiary healthcare hospital

Background

Following the 2009 H1N1 pandemic, there have been a large number of studies focusing on the epidemiology and outcomes of influenza A infection; however, there have been fewer studies focused on other respiratory viral infections.

Objectives

To define the epidemiology and outcomes of non-influenza respiratory viral infections in hospitalized adults.

Patients/Methods

Data on all patients ≥18 years of age with a positive molecular respiratory viral assay who were hospitalized at a single tertiary healthcare system in Chicago, IL, from retrospectively collected and analyzed.

Results

Over the study period, 503 of 46 024 (1·1%) admitted patients had a positive RVP result. Human rhinovirus was the most commonly detected virus followed by influenza A, human metapneumovirus, respiratory syncytial virus, and parainfluenza virus, adenovirus, and influenza B, respectively. Infection in immunocompromised patients was associated with a higher rate of progression to pneumonia and death.

Conclusions

Non-influenza respiratory viral infections are commonly detected among adults admitted to the hospital and can cause serious illness. The data can inform the prioritization of research into novel antiviral therapies for these infections.

Circulation of other respiratory viruses and viral co-infection during the 2009 pandemic influenza

Coinciding with the pandemic wave of the influenza A(H1N1)pdm09 virus, other respiratory viruses have co-circulated in our area and were responsible for many acute respiratory infections and influenza-like illness (ILI). Apart from the pandemic virus that was responsible for most ILI cases, incidence rates of other viruses have varied among geographical areas. In general, human rhinovirus was the most frequent among individuals from the community, and respiratory syncytial virus among hospitalized patients. Detection rates of other respiratory viruses such as human metapneumovirus, adenovirus or parainfluenza viruses have been much lower. On the basis of an interference mechanism, human rhinovirus may contribute to modulate the pandemic wave, although available data are not conclusive to support this hypothesis. In contrast, the epidemic wave of respiratory syncytial virus during 2009–2010 was similar to previous seasons. Overall, incidence rates of respiratory viruses other than influenza did not change significantly during the pandemic season compared to other seasons. No association has been found between coinfection of pandemic influenza and other respiratory viruses with the prognosis of patients with influenza. The involvement of clinical virology laboratories in the etiological diagnosis of ILI cases has improved and has optimized diagnostic procedures.

Evaluation of the BioFire FilmArray respiratory panel and the GenMark eSensor respiratory viral panel on lower respiratory tract specimens

We evaluated the performance characteristics of the FilmArray respiratory panel and the eSensor respiratory viral panel on clinical and spiked lower respiratory tract specimens (LRTS). The overall agreement between the two methods was 89.5% (51/57). The lower limit of detection of both assays for all targets in LRTS was comparable to that for nasopharyngeal swab specimens.

George K, Walsh TJ. Human rhinoviruses

Human rhinoviruses (HRVs), first discovered in the 1950s, are responsible for more than one-half of cold-like illnesses and cost billions of dollars annually in medical visits and missed days of work. Advances in molecular methods have enhanced our understanding of the genomic structure of HRV and have led to the characterization of three genetically distinct HRV groups, designated groups A, B, and C, within the genus Enterovirus and the family Picornaviridae. HRVs are traditionally associated with upper respiratory tract infection, otitis media, and sinusitis. In recent years, the increasing implementation of PCR assays for respiratory virus detection in clinical laboratories has facilitated the recognition of HRV as a lower respiratory tract pathogen, particularly in patients with asthma, infants, elderly patients, and immunocompromised hosts. Cultured isolates of HRV remain important for studies of viral characteristics and disease pathogenesis. Indeed, whether the clinical manifestations of HRV are related directly to viral pathogenicity or secondary to the host immune response is the subject of ongoing research. There are currently no approved antiviral therapies for HRVs, and treatment remains primarily supportive. This review provides a comprehensive, up-to-date assessment of the basic virology, pathogenesis, clinical epidemiology, and laboratory features of and treatment and prevention strategies for HRVs.

Laboratory detection of respiratory viruses by automated techniques

Advances in clinical virology for detecting respiratory viruses have been focused on nucleic acids amplification techniques, which have converted in the reference method for the diagnosis of acute respiratory infections of viral aetiology. Improvements of current commercial molecular assays to reduce hands-on-time rely on two strategies, a stepwise automation (semi-automation) and the complete automation of the whole procedure. Contributions to the former strategy have been the use of automated nucleic acids extractors, multiplex PCR, real-time PCR and/or DNA arrays for detection of amplicons. Commercial fully-automated molecular systems are now available for the detection of respiratory viruses. Some of them could convert in point-of-care methods substituting antigen tests for detection of respiratory syncytial virus and influenza A and B viruses. This article describes laboratory methods for detection of respiratory viruses. A cost-effective and rational diagnostic algorithm is proposed, considering technical aspects of the available assays, infrastructure possibilities of each laboratory and clinic-epidemiologic factors of the infection.

Diagnostic performance of two highly multiplexed respiratory virus assays in a pediatric cohort

Background

Rapid detection of respiratory viruses is important for management and infection control in hospitalized patients. Multiplex nucleic acid tests (NATs) have begun to replace conventional methods as gold standards for respiratory virus detection.

Objective

To compare the performance of two large multiplex NATS, ResPlex II (RPII) and Respiratory Virus Surveillance kit with electrospray ionization mass spectrometry (RVS/MS) using nasopharyngeal aspirates (NPAs) from hospitalized children who had been tested previously with conventional methods.

Study design

Stored residual NPAs (N = 306) were tested concomitantly by RPII and RVS/MS. Alternate NATs were used to adjudicate discordant results.

Results

More viruses were detected with multiplex NATs (RPII, 110; RVS/MS, 109) than conventional assays (86); diagnostic gain was primarily for fastidious viruses (coronaviruses and enteroviruses [EVs]/human rhinoviruses [HRVs]). Total positive and negative agreement between the multiplex NATs for all viruses detected was quite high (86% positive agreement, 99% negative agreement). Most individual viruses were detected with fairly equivalent accuracy by the multiplex NATs, except for adenoviruses (RPII sensitivity 40%) and human metapneumovirus (RVS/MS sensitivity 42%). RPII had the advantage of detecting EVs and HRVs, however, it demonstrated considerable EV/HRV cross-reactivity (29 HRV-positive specimens by real-time PCR were positive for EV by RPII and 21 specimens positive for HRV only by RT-PCR were dual positive for EV/HRV by RPII). RPII also had reduced sensitivity for HRV detection (in 36 specimens, HRV was detected by RT-PCR but not by RPII).

Conclusions

Both multiplex NATs were promising, but had notable limitations.