Successful systemic high-dose ribavirin treatment of respiratory syncytial virus-induced infections occurring pre-engraftment in allogeneic hematopoietic stem cell transplant recipients

Occurrence of Central Nervous System Complications of Respiratory Syncytial Virus Infections: A Systematic Review with Meta-Analysis

An increasing base of evidence suggests that respiratory syncytial virus (RSV) infections may be associated with neurological complications. In accord with the PRISMA statement, we performed a systematic review and meta-analysis on the occurrence of encephalitis and encephalopathy associated with documented RSV infections. PubMed, Embase, and Scopus databases were searched for eligible observational studies published up to 10 April 2024. Raw data included the occurrence of RSV infections among cases of encephalitis and/or encephalopathy and cases of encephalitis and/or encephalopathy among series of RSV infections. Data were pooled in a random effects model. Case reports were also collected, and their data pooled as a cumulative series. Heterogeneity was assessed using the I2 measure, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 15 studies for a total of 7719 RSV infections and 1631 cases of encephalitis were analyzed. Moreover, 27 case reports and case series were retrieved, for a total of 84 individual cases of encephalitis/encephalopathy occurring during a documented RSV infection. A pooled prevalence of 2.20 cases of encephalitis/encephalopathy per 100 RSV cases (I2 = 99%) was calculated, while a prevalence of RSV infections among cases of encephalitis/encephalopathy was estimated to 3.53 per 100 cases for studies on respiratory specimens (I2 = 48%) and 0.37 per cases on central nervous system (CNS) specimens (I2 = 0%). Detection of RSV within the CNS was relatively rare (17.86% of pooled case reports), being associated with male gender (adjusted odds ratio [aOR] 5.021, 95% confidence interval [95%CI] 1.104 to 22.831) and recovery with long-term sequelae (aOR 5.699, 95%CI 1.152; 28.183). Case fatality ratio was estimated to be 0.43 per 100 cases on observational studies and 10.71% in case reports, a difference likely due to publication bias. In summary, RSV represented a not frequent but notable cause of encephalitis/encephalopathy in adults and children. The paucity of available studies not only recommends a cautious appraisal of our results but stresses the clinical significance of future studies on incident cases of encephalitis and/or encephalopathy.

Respiratory Syncytial Virus Infections in Recipients of Bone Marrow Transplants: A Systematic Review and Meta-Analysis

Human Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infections. Usually associated with infants and children, an increasing amount of evidence suggests that RSV can cause substantial morbidity and mortality in immunocompromised individuals, including recipients of bone marrow transplantation (BMT). The present systematic review was therefore designed in accordance with the PRISMA guidelines to collect available evidence about RSV infections in BMT recipients. Three medical databases (PubMed, Embase, and MedRxiv) were therefore searched for eligible observational studies published up to 30 September 2023 and collected cases were pooled in a random-effects model. Heterogeneity was assessed using I2 statistics. Reporting bias was assessed by means of funnel plots and regression analysis. Overall, 30 studies were retrieved, including 20,067 BMT cases and 821 RSV infection episodes. Of them, 351 were lower respiratory tract infections, and a total of 78 RSV-related deaths were collected. A pooled attack rate of 5.40% (95% confidence interval [95%CI] 3.81 to 7.60) was identified, with a corresponding incidence rate of 14.77 cases per 1000 person-years (95%CI 9.43 to 20.11), and a case fatality ratio (CFR) of 7.28% (95%CI 4.94 to 10.60). Attack rates were higher in adults (8.49%, 95%CI 5.16 to 13.67) than in children (4.79%, 95%CI 3.05 to 7.45), with similar CFR (5.99%, 95%CI 2.31 to 14.63 vs. 5.85%, 95%CI 3.35 to 10.02). By assuming RSV attack rates as a reference group, influenza (RR 0.518; 95%CI 0.446 to 0.601), adenovirus (RR 0.679, 95%CI 0.553 to 0.830), and human metapneumovirus (RR 0.536, 95%CI 0.438 to 0.655) were associated with a substantially reduced risk for developing corresponding respiratory infection. Despite the heterogeneous settings and the uneven proportion of adult and pediatric cases, our study has identified high attack rates and a substantial CFR of RSV in recipients of BMT, stressing the importance of specifically tailored preventive strategies and the need for effective treatment options.

American Society of Transplantation and Cellular Therapy Series: #7 - Management of Respiratory Syncytial Virus Infections in Hematopoietic Cell Transplant Recipients

The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy (ASTCT) partnered with its Transplant Infectious Disease Special Interest Group (TID-SIG) to update the 2009 compendium-style infectious disease guidelines for hematopoietic cell transplantation (HCT). A new approach was adopted to better serve clinical providers by publishing each standalone topic in the infectious disease series in a concise format of frequently asked questions (FAQ), tables, and figures. Experts in HCT and infectious diseases identified FAQs and then provided answers based on the strength of the recommendation and the level of supporting evidence. In the seventh guideline in the series, we focus on the respiratory syncytial virus (RSV) with FAQs addressing epidemiology, clinical diagnosis, prophylaxis, and treatment. Special consideration was given to RSV in pediatric, cord blood, haploidentical, and T cell-depleted HCT and chimeric antigen receptor T cell therapy recipients, as well as to identify future research directions.

Burden of respiratory syncytial virus infection in older and high-risk adults: a systematic review and meta-analysis of the evidence from developed countries

Background

Respiratory syncytial virus (RSV) significantly impacts the health of older and high-risk adults (those with comorbidities). We aimed to synthesise the evidence on RSV disease burden and RSV-related healthcare utilisation in both populations.

Methods

We searched Embase and MEDLINE for papers published between 2000 and 2019 reporting the burden and clinical presentation of symptomatic RSV infection and the associated healthcare utilisation in developed countries in adults aged ≥60 years or at high risk. We calculated pooled estimates using random-effects inverse variance-weighted meta-analysis.

Results

103 out of 3429 articles met the inclusion criteria. Among older adults, RSV caused 4.66% (95% CI 3.34–6.48%) of symptomatic respiratory infections in annual studies and 7.80% (95% CI 5.77–10.45%) in seasonal studies; RSV-related case fatality proportion (CFP) was 8.18% (95% CI 5.54–11.94%). Among high-risk adults, RSV caused 7.03% (95% CI 5.18–9.48%) of symptomatic respiratory infections in annual studies, and 7.69% (95% CI 6.23–9.46%) in seasonal studies; CFP was 9.88% (95% CI 6.66–14.43%). Data paucity impaired the calculation of estimates on population incidence, clinical presentation, severe outcomes and healthcare-related utilisation.

Conclusions

Older and high-risk adults frequently experience symptomatic RSV infection, with appreciable mortality; however, detailed data are lacking. Increased surveillance and research are needed to quantify population-based disease burden and facilitate RSV treatments and vaccine development.

Antiviral Therapeutics in Pediatric Transplant Recipients

Recipients of solid organ and hematopoietic stem cell transplantation undergo substantial immune suppression, placing them at risk for opportunistic viral infection. Few randomized controlled trials have been dedicated to the treatment of viral infections in children, and current practices are extrapolated from data generated from adult patients. Here we discuss the prevention and treatment of viral infections using available antiviral drugs, as well as novel agents that may provide benefit to pediatric patients in the future.

Oral Versus Aerosolized Ribavirin for the Treatment of Respiratory Syncytial Virus Infections in Hematopoietic Cell Transplant Recipients

Background

The use of oral ribavirin (RBV) for respiratory syncytial virus (RSV) infections is not well studied. With the drastic increase in the cost of aerosolized RBV, we aimed to compare outcomes of hematopoietic cell transplant (HCT) recipients treated with oral or aerosolized RBV for RSV infections.

Methods

We reviewed the records of 124 HCT recipients with RSV infections treated with oral or aerosolized RBV from September 2014 through April 2017. An immunodeficiency scoring index (ISI) was used to classify patients as low, moderate, or high risk for progression to lower respiratory infection (LRI) or death.

Results

Seventy patients (56%) received aerosolized RBV and 54 (44%) oral RBV. Both groups had a 27% rate of progression to LRI (P = 1.00). Mortality rates did not significantly differ between groups (30-day: aerosolized 10%, oral 9%, P = 1.00; 90-day: aerosolized 23%, oral 11%, P = .10). Classification and regression tree analysis identified ISI ≥7 as an independent predictor of 30-day mortality. For patients with ISI ≥7, 30-day mortality was significantly increased overall, yet remained similar between the aerosolized and oral therapy groups (33% for both). After propensity score adjustment, Cox proportional hazards models showed similar mortality rates between oral and aerosolized therapy groups (30-day: hazard ratio [HR], 1.12 [95% confidence interval {CI}, .345–3.65, P = .845).

Conclusions

HCT recipients with RSV infections had similar outcomes when treated with aerosolized or oral RBV. Oral ribavirin may be an effective alternative to aerosolized RBV, with potential significant cost savings.

Seasonality and coinfection of bronchiolitis: epidemiological specificity and consequences in terms of prophylaxis in tropical climate

OBJECTIVE

To describe the viruses involved, seasonality and coinfection in hospitalised children with suspected bronchiolitis.

METHODS

Over the period 1/07/2007 to 31/12/2008, all children hospitalised for bronchiolitis in the paediatric ward were prospectively included, and had respiratory syncytial virus (RSV) screenings. We retrospectively tested all samples for RSVA, RSVB, rhinovirus (RV), human metapneumovirus, parainfluenza 1, 2, 3, 4, influenza A and influenza B.

RESULTS

198 children were tested, and 23% were negative for all viruses. RSVA was predominant in 2008 (64% of all viruses) and RSVB in 2007 (66% of all viruses). RV was frequent during both seasons (24% of all viruses). Flu was not found during the study period. Virus distribution was similar regardless of season or age, and identical to typical patterns in temperate countries. Coinfections were less frequent than in temperate regions because respiratory virus seasons seem to be better separated. The bronchiolitis season started in August and finished in December with a peak in October.

CONCLUSION

The specific seasonality of bronchiolitis infection requires palivizumab prophylaxis starting in early July for high-risk infants.

Paramyxovirus infections in hematopoietic cell transplant recipients

PURPOSE OF REVIEW

In hematopoietic cell transplant (HCT) recipients, paramyxovirus infections are major viral respiratory tract infections that, if they progress to lower respiratory tract infections, are associated with reduced survival rates in this population. There are important knowledge gaps regarding treatment decisions for HCT recipients with these infections and in the identification of risk factors that predict infection severity. Here, we review recent data on paramyxovirus infections in HCT recipients focusing on risk factors, new diagnostic and prognostic tools, and management including new drugs and vaccines under development.

RECENT FINDINGS

Multiplexed molecular assays associated with immunodeficiency scoring index for respiratory syncytial virus (RSV) have improved our understanding of the epidemiology of RSV and other paramyxovirus infections and the risk factors for worse outcomes. Novel antiviral drugs, monoclonal antibodies, and vaccines are under evaluation with mixed preliminary results.

SUMMARY

Advances in our knowledge of paramyxovirus infections in HCT recipients in the last two decades contributed to better strategies for management and prevention of these infections. A widespread understanding of how to stratify HCT recipients with paramyxovirus infections who would benefit most from antiviral therapy remains to be ascertained. Vaccines and new drugs under development may mitigate the burden of paramyxovirus infections.

Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies

In the USA and other western nations, respiratory syncytial virus is one of the most commonly encountered respiratory viruses among patients who have been diagnosed with a hematologic malignancy or who have undergone a stem cell transplant. Multiple studies have been performed to evaluate the complications associated with respiratory syncytial virus infections. Other studies have evaluated therapeutic agents and strategies in which these agents can be used. There have also been numerous reports of outbreaks in bone marrow transplant units and oncology wards, where infection control measures have been invaluable in controlling the spread of disease. However, despite these novel approaches, respiratory syncytial virus continues to be potentially fatal in immunocompromised populations. In this review, we discuss the incidence of respiratory syncytial viral infections, risk factors associated with progression from upper respiratory tract infection to lower respiratory tract infection, other complications and outcomes (including mortality), management strategies, and prevention strategies in patients with a hematologic malignancy and in hematopoietic cell transplant recipients.

Respiratory Virus Infections of the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Respiratory virus infections in hematologic stem cell transplant recipients and patients with hematologic malignancies are increasingly recognized as a cause of significant morbidity and mortality. The often overlapping clinical presentation makes molecular diagnostic strategies imperative for rapid diagnosis and to inform understanding of the changing epidemiology of each of the respiratory viruses. Most respiratory virus infections are managed with supportive therapy, although there is effective antiviral therapy for influenza. The primary focus should remain on primary prevention infection control procedures and isolation precautions, avoidance of ill contacts, and vaccination for influenza.

Treatment stratification of respiratory syncytial virus infection in allogeneic stem cell transplantation

BACKGROUND

Due to paucity of evidence to guide management of allogeneic haematopoietic stem cell transplantation (allo-HSCT) patients with respiratory syncytial virus (RSV) infections national and international guidelines make disparate recommendations.

METHODS

The outcomes of allo-HSCT recipients with RSV infection between 2015 and 2017 were assessed using the following treatment stratification; upper respiratory tract infections (URTI) being actively monitored and lower respiratory tract infections (LRTI) treated with short courses of oral ribavirin combined with intravenous immunoglobulin (IVIG, 2 g/kg).

RESULTS

During the study period 49 RSV episodes were diagnosed (47% URTI and 53% LRTI). All patients with URTI recovered without pharmacological intervention. Progression from URTI to LRTI occurred in 15%. Treatment with oral ribavirin given until significant symptomatic improvement (median 7 days [3-12]) and IVIG for LRTI was generally well tolerated. RSV-attributable mortality was low (2%).

CONCLUSIONS

In this cohort study, we demonstrate that active monitoring of allo-HSCT patients with RSV in the absence of LRTI was only associated with progression to LRTI in 15% of our patients and therefore appears to be a safe approach. Short course oral ribavirin in combination with IVIG was effective and well-tolerated for LRTI making it a practical alternative to aerosolised ribavirin. This approach was beneficial in reducing hospitalisation, saving nursing times and by using oral as opposed to nebulised ribavirin.

Clinical characteristics and treatment outcomes among respiratory syncytial virus (RSV)-infected hematologic malignancy and hematopoietic stem cell transplant recipients receiving palivizumab

Palivizumab has been used to treat respiratory syncytial virus (RSV)-infected hematologic malignancy patients at our institution based on limited published data. We conducted this retrospective study to evaluate clinical outcomes and mortality rates of RSV-infected hematologic malignancy patients from 2007 to 2016. A total of 67 patients (19 received palivizumab and 47 received supportive care) were identified. Palivizumab-treated patients had a significantly higher proportion of underlying ischemic heart disease, graft-versus-host-disease, hypogammaglobulinemia, and concomitant pulmonary infections. There were no significant differences in mortality rates or readmission rates between the two groups. The estimated odds ratio for death in patients receiving palivizumab after adjusting for propensity scores and covariates were 0.12 ([0.01, 1.32], p = .08) and 0.09 ([0.01, 1.03], p = .05) respectively. After adjustment for factors associated with severity of illness, there was no difference in mortality among patients treated with palivizumab.

Antiviral treatment of severe non-influenza respiratory virus infection

PURPOSE OF REVIEW

Non-influenza respiratory virus infections are a frequent cause of severe acute respiratory infections, especially in infants, the elderly, and the immunocompromised. We review here the current treatment options for non-influenza respiratory viruses and promising candidate antiviral agents currently in development.

RECENT FINDINGS

Small molecule antiviral agents active against respiratory syncytial virus (RSV), such as ALS-8176 and GS-5806, show considerable promise in challenge studies and are undergoing late-phase clinical trials in hospitalised adults and children. Monoclonal antibodies (mAbs) active against non-influenza respiratory viruses are broadly at a preclinical stage. Broad-spectrum antivirals, such as favipiravir and nitrazoxanide, have potential utility in treating illness caused by non-influenza respiratory viruses but further definitive clinical trials are needed.

SUMMARY

Severe non-influenza respiratory virus infection is common and current treatment is largely supportive. Ribavirin is used in immunocompromised patients but its use is limited by toxicity and the evidence for its efficacy is weak. Effective antiviral treatment for RSV may shortly become available, pending the results of ongoing clinical trials. For other non-influenza viruses, effective treatments may become available in the medium term. Early detection of respiratory viruses with rapid molecular test platforms will be crucial in differentiating virus types and directing the prompt initiation of novel treatments when available.

Comparative effectiveness of aerosolized versus oral ribavirin for the treatment of respiratory syncytial virus infections: A single-center retrospective cohort study and review of the literature

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of viral infections in immunocompromised hosts and is associated with significant morbidity and mortality. In January 2015, our institution switched from aerosolized to oral ribavirin (RBV) for primary treatment of RSV infection among high-risk immunocompromised adult patients. The objective of the study was to evaluate the clinical and economic outcomes associated with this switch.

METHODS

Retrospective cohort analysis of adult patients diagnosed with RSV infection and treated with RBV between January 1, 2013, and May 31, 2016.

RESULTS

Of 46 patients, 20 (43%) patients received oral RBV and 26 (57%) received aerosolized RBV. Underlying conditions included lung transplant (n = 22), hematopoietic cell transplant (n = 16), hematological malignancy (n = 5), and structural lung diseases (n = 4). At the time of RSV diagnosis, 42 (91%) were hospitalized, 36 (78%) had clinical and radiographic evidence of lower respiratory tract infection (RTI), 9 (20%) were admitted to the ICU, and 4 (9%) required intubation. There were no differences in clinical outcomes between the 2 groups with regard to adverse events, progression from upper to lower RTI, escalation of care, or 30-day mortality. Three (15%) in the oral group and 1 (4%) in the aerosolized group died within 30 days (P = .33). The cost avoidance attributable to the switch in therapy over 1 year is $1.2 million.

CONCLUSION

Oral RBV appears to be a safe and cost-effective alternative to aerosolized RBV for the management of RSV infection in immunocompromised patients. Larger studies are needed to validate the safety and efficacy of this approach.

Respiratory Syncytial Virus Infection Control Challenges with a Novel Polymerase Chain Reaction Assay in a Tertiary Medical Center

OBJECTIVES To evaluate host characteristics, mode of infection acquisition, and infection control procedures in patients with a positive respiratory syncytial virus (RSV) test result after the introduction of the GenXpert Influenza/RSV polymerase chain reaction (PCR) assay. DESIGN Retrospective cohort study. PATIENTS Adults with a positive PCR test result for RSV who were hospitalized in a tertiary academic medical center between January 2015 and December 2016 were included in this study. Our infection control policy applies contact isolation precautions only for immunocompromised patients. METHODS Patients were identified through 2 databases, 1 consisting of patients isolated because of RSV infection and 1 with automatically collected laboratory results. Baseline and clinical characteristics were collected through a retrospective medical chart review. The rate of and clinical factors associated with healthcare-associated RSV infections were evaluated. RESULTS In total, 108 episodes in 106 patients hospitalized with a positive Xpert RSV test result were recorded during the study period. Among them, 11 episodes were healthcare-associated infections (HAIs) and 97 were community-acquired infections (CAIs). The mean length of hospital stay (LOS, 40.2 vs 11.2 days), the mean number of room switches (3.5 vs 1.7) and ward switches (1.5 vs 0.4), and the mean numbers of contact patients (9.9 vs 3.8) were significantly longer and higher in the HAI group than in the CAI group (P<.0001). Surveillance of microbiology records and clinical data did not reveal evidence for a cluster or an epidemic during the 2-year observation period. CONCLUSIONS The introduction of a rapid molecular diagnostic test systematically applied to patients with influenza-like illness may challenge current infection control policies. In our study, patients with HAIs had a prolonged hospital stay and a high number of contact patients, and they switched rooms and wards frequently. Infect Control Hosp Epidemiol 2017;38:1291-1297.

Community acquired respiratory virus infections in cancer patients-Guideline on diagnosis and management by the Infectious Diseases Working Party of the German Society for haematology and Medical Oncology

BACKGROUND

Community acquired viruses (CRVs) may cause severe disease in cancer patients. Thus, efforts should be made to diagnose CRV rapidly and manage CRV infections accordingly.

METHODS

A panel of 18 clinicians from the Infectious Diseases Working Party of the German Society for Haematology and Medical Oncology have convened to assess the available literature and provide recommendations on the management of CRV infections including influenza, respiratory syncytial virus, parainfluenza virus, human metapneumovirus and adenovirus.

RESULTS

CRV infections in cancer patients may lead to pneumonia in approximately 30% of the cases, with an associated mortality of around 25%. For diagnosis of a CRV infection, combined nasal/throat swabs or washes/aspirates give the best results and nucleic acid amplification based-techniques (NAT) should be used to detect the pathogen. Hand hygiene, contact isolation and face masks have been shown to be of benefit as general infection management. Causal treatment can be given for influenza, using a neuraminidase inhibitor, and respiratory syncytial virus, using ribavirin in addition to intravenous immunoglobulins. Ribavirin has also been used to treat parainfluenza virus and human metapneumovirus, but data are inconclusive in this setting. Cidofovir is used to treat adenovirus pneumonitis.

CONCLUSIONS

CRV infections may pose a vital threat to patients with underlying malignancy. This guideline provides information on diagnosis and treatment to improve the outcome.

Maternal Effects of Respiratory Syncytial Virus Infection during Pregnancy

Clarifying these effects could show potential benefits of RSV vaccination of pregnant women.

Given the illness and deaths caused by respiratory syncytial virus (RSV) infection during the first year of life, preventing infant RSV infections through maternal vaccination is intriguing. However, little is known about the extent and maternal effects of RSV infection during pregnancy. We describe 3 cases of maternal RSV infection diagnosed at a US center during winter 2014. Case-patient 1 (26 years old, week 33 of gestation) received a diagnosis of RSV infection and required mechanical ventilation. Case-patient 2 (27 years old, week 34 of gestation) received a diagnosis of infection with influenza A(H1N1) virus and RSV and required mechanical ventilation. Case-patient 3 (21 years old, week 32 of gestation) received a diagnosis of group A streptococcus pharyngitis and RSV infection and was monitored as an outpatient. Clarifying the effects of maternal RSV infection could yield valuable insights into potential maternal and fetal benefits of an effective RSV vaccination program.

Current practices for treatment of respiratory syncytial virus and other non-influenza respiratory viruses in high-risk patient populations: a survey of institutions in the Midwestern Respiratory Virus Collaborative

Background

The optimal treatment for respiratory syncytial virus (RSV) infection in adult immunocompromised patients is unknown. We assessed the management of RSV and other non‐influenza respiratory viruses in Midwestern transplant centers.

Methods

A survey assessing strategies for RSV and other non‐influenza respiratory viral infections was sent to 13 centers.

Results

Multiplex polymerase chain reaction assay was used for diagnosis in 11/12 centers. Eight of 12 centers used inhaled ribavirin (RBV) in some patient populations. Barriers included cost, safety, lack of evidence, and inconvenience. Six of 12 used intravenous immunoglobulin (IVIG), mostly in combination with RBV. Inhaled RBV was used more than oral, and in the post‐stem cell transplant population, patients with lower respiratory tract infection (LRTI), graft‐versus‐host disease, and more recent transplantation were treated at higher rates. Ten centers had experience with lung transplant patients; all used either oral or inhaled RBV for LRTI, 6/10 treated upper respiratory tract infection (URTI). No center treated non‐lung solid organ transplant (SOT) recipients with URTI; 7/11 would use oral or inhaled RBV in the same group with LRTI. Patients with hematologic malignancy without hematopoietic stem cell transplantation were treated with RBV at a similar frequency to non‐lung SOT recipients. Three of 12 centers, in severe cases, treated parainfluenza and metapneumovirus, and 1/12 treated coronavirus.

Conclusions

Treatment of RSV in immunocompromised patients varied greatly. While most centers treat LRTI, treatment of URTI was variable. No consensus was found regarding the use of oral versus inhaled RBV, or the use of IVIG. The presence of such heterogeneity demonstrates the need for further studies defining optimal treatment of RSV in immunocompromised hosts.

How I treat respiratory viral infections in the setting of intensive chemotherapy or hematopoietic cell transplantation

The widespread use of multiplex molecular diagnostics has led to a significant increase in the detection of respiratory viruses in patients undergoing cytotoxic chemotherapy and hematopoietic cell transplantation (HCT). Respiratory viruses initially infect the upper respiratory tract and then progress to lower respiratory tract disease in a subset of patients. Lower respiratory tract disease can manifest itself as airflow obstruction or viral pneumonia, which can be fatal. Infection in HCT candidates may require delay of transplantation. The risk of progression differs between viruses and immunosuppressive regimens. Risk factors for progression and severity scores have been described, which may allow targeting treatment to high-risk patients. Ribavirin is the only antiviral treatment option for noninfluenza respiratory viruses; however, high-quality data demonstrating its efficacy and relative advantages of the aerosolized versus oral form are lacking. There are significant unmet needs, including data defining the virologic characteristics and clinical significance of human rhinoviruses, human coronaviruses, human metapneumovirus, and human bocavirus, as well as the need for new treatment and preventative options.

Respiratory syncytial virus, an ongoing medical dilemma: an expert commentary on respiratory syncytial virus prophylactic and therapeutic pharmaceuticals currently in clinical trials

As the most important viral cause of severe respiratory disease in infants and increasing recognition as important in the elderly and immunocompromised, respiratory syncytial virus (RSV) is responsible for a massive health burden worldwide. Prophylactic antibodies were successfully developed against RSV. However, their use is restricted to a small group of infants considered at high risk of severe RSV disease. There is still no specific therapeutics or vaccines to combat RSV. As such, it remains a major unmet medical need for most individuals. The World Health Organisations International Clinical Trials Registry Platform (WHO ICTRP) and PubMed were used to identify and review all RSV vaccine, prophylactic and therapeutic candidates currently in clinical trials. This review presents an expert commentary on all RSV-specific prophylactic and therapeutic candidates that have entered clinical trials since 2008.

Poor positive predictive value of influenza-like illness criteria in adult transplant patients: a case for multiplex respiratory virus PCR testing

Background

Respiratory viral infections (RVIs) are a significant cause of morbidity and mortality among transplant patients. The CDC's influenza‐like illness (ILI) criteria (fever ≥100°F with cough and/or sore throat) are a screening tool for influenza with unknown applicability to the transplant population.

Methods

We reviewed all respiratory virus PCR tests performed on adult patients with a history of solid organ (SOT) or stem cell transplantation (HSCT) during the 2012–2013 influenza season. The positive (PPV) and negative predictive values (NPV) of ILI criteria were calculated.

Results

Of 126 transplant patients (66 HSCT, 60 SOT), 54 (42.8%) tested positive for an RVI by PCR: 24 influenza and 30 non‐influenza. Of 30 patients who met ILI criteria, 12 (40%) were positive for influenza. The PPV and NPV of ILI for influenza were 50% and 82.4%, respectively. Mortality was low (3.7%), but morbidity was high (14.8% required ICU stay) among transplant patients diagnosed with RVI.

Conclusions

Influenza and non‐influenza RVIs are associated with significant morbidity among transplant patients. CDC ILI criteria correlate poorly with PCR‐positive cases of influenza in transplant patients, but may be useful in excluding the diagnosis. Routine RVI PCR testing is recommended for better diagnosis and improved antiviral use in transplant patients with suspected RVI.

Identification of CCL2, RARRES2 and EFNB2 as host cell factors that influence the multistep replication of respiratory syncytial virus

Human respiratory syncytial virus (RSV) is a major causative agent of respiratory tract infections in children worldwide. Preterm children or those with underlying cardiopulmonary disorders are at particularly high risk of developing severe and lethal RSV respiratory tract infections; however, there are currently no effective vaccines or anti-viral drugs. To identify targets for the development of drugs to treat RSV infections, we investigated host cell factors involved in the replication of RSV. To this end, MDCK cells with low susceptibility to RSV were transfected with cDNA libraries derived from RSV-susceptible human lung or HeLa cells. A microarray analysis was subsequently performed on parental MDCK cells and MDCK cells that were converted to an RSV-susceptible form. Among the genes identified, chemokine (C-C motif) ligand 2 (CCL2), retinoic acid receptor responder protein 2 (RARRES2) and ephrin-B2 (EFNB2) had a positive effect on RSV replication. Expression of these genes in MDCK cells resulted in a 10- to 100-fold increase in RSV replication. CCL2 expression also disrupted the distribution of claudin-1, a tight junction protein, suggesting that CCL2 plays a role in claudin-based tight junction formation during RSV replication. The knockdown of EFNB2 and RARRES2 by siRNA in RSV-susceptible cell lines (HEp-2 and A549) resulted in reduced RSV replication, suggesting that EFNB2 and RARRES2 participate in RSV replication. Together, our findings suggest that CCL2, RARRES2 and EFNB2 are host cell factors involved in RSV replication.

Oral Ribavirin for the Treatment of Noninfluenza Respiratory Viral Infections: A Systematic Review

OBJECTIVE

To review clinical outcomes data for patients treated with oral ribavirin for noninfluenza respiratory viral infections (NIRVIs).

DATA SOURCES

MEDLINE, EMBASE, and PubMed Central (1972 to June 1, 2015) were queried with the following search term combinations: "Oral" AND "ribavirin" AND ("respiratory syncytial virus" OR "metapneumovirus" OR "parainfluenza" OR "coronavirus" OR "rhinovirus" OR "enterovirus" OR "adenovirus").

STUDY SELECTION AND DATA EXTRACTION

Included studies must have characterized the clinical outcomes of a cohort of patients treated with oral ribavirin for symptomatic NIRVIs. Case reports and series with <5 cases, conference abstracts, and articles written in languages other than English were excluded.

DATA SYNTHESIS

Of the 1256 unique reports, 15 met inclusion criteria: 12 retrospective, 3 prospective, and 3 comparative with untreated control groups. All studies except for 2 Middle East respiratory syndrome coronavirus (MERS-CoV) studies were in immunocompromised patients (9 malignancy/stem cell transplant, 4 lung transplant). The mortality rate ranged from 0% to 31% in malignancy/stem cell transplant recipients treated with oral ribavirin, and 1/108 (0.9%) ribavirin-treated lung transplant recipients died at 30 days. Three studies (one each for malignancy, lung transplant, and MERS-CoV) suggested a clinical outcomes benefit with oral ribavirin compared with supportive care alone; however, the nonrandomized design precludes efficacy determination. Hemolysis was the most common adverse reaction, occurring in 14% (54/375) of patients. Ribavirin was discontinued in 4% of patients secondary to adverse reactions.

CONCLUSIONS

Oral ribavirin should be considered for the treatment of NIRVI in immunocompromised adults (malignancy/stem cell transplant or lung transplant) or adults with MERS-CoV.

Management of respiratory viral infections in hematopoietic cell transplant recipients and patients with hematologic malignancies

Despite preventive strategies and increased awareness, a high incidence of respiratory viral infections still occur in patients with hematologic malignancies (HMs) and in recipients of hematopoietic cell transplant (HCT). Progression of these viral infections to lower respiratory tract may prove fatal, especially in HCT recipients. Increasing evidence on the successful use of ribavirin (alone or in combination with immunomodulators) for the treatment of respiratory syncytial virus infections in HM patients and HCT recipients is available from retrospective studies; however, prospective clinical trials are necessary to establish its efficacy with confidence. The impact on progression to pneumonitis and/or mortality of treating parainfluenza virus infections with available (ribavirin) or investigational (DAS181) antiviral agents still needs to be determined. Influenza infections have been successfully treated with neuraminidase inhibitors (oseltamivir or zanamivir); however, the efficacy of these agents for influenza pneumonia has not been established, and immunocompromised patients are highly susceptible to emergence of antiviral drug resistance, most probably due to prolonged viral shedding. Infection control measures and an appreciation of the complications following respiratory viral infections in immunocompromised patients remain crucial for reducing transmission. Future studies should focus on strategies to identify patients at high risk for increased morbidity and mortality from these infections and to determine the efficacy of novel or available antiviral drugs.

Predictors of viral pneumonia in patients with community-acquired pneumonia

BACKGROUND

Viruses are increasingly recognized as major causes of community-acquired pneumonia (CAP). Few studies have investigated the clinical predictors of viral pneumonia, and the results have been inconsistent. In this study, the clinical predictors of viral pneumonia were investigated in terms of their utility as indicators for viral pneumonia in patients with CAP.

METHODS

Adult patients (≥ 18 years old) with CAP, tested by polymerase chain reaction (PCR) for respiratory virus, at two teaching hospitals between October 2010 and May 2013, were identified retrospectively. Demographic and clinical data were collected by reviewing the hospital electronic medical records.

RESULTS

During the study period, 456 patients with CAP were identified who met the definition, and 327 (72%) patients were tested using the respiratory virus PCR detection test. Viral pneumonia (n = 60) was associated with rhinorrhea, a higher lymphocyte fraction in the white blood cells, lower serum creatinine and ground-glass opacity (GGO) in radiology results, compared to non-viral pneumonia (n = 250) (p < 0.05, each). In a multivariate analysis, rhinorrhea (Odd ratio (OR) 3.52; 95% Confidence interval (CI), 1.58-7.87) and GGO (OR 4.68; 95% CI, 2.48-8.89) were revealed as independent risk factors for viral pneumonia in patients with CAP. The sensitivity, specificity, positive- and negative-predictive values (PPV and NPV) of rhinorrhea were 22, 91, 36 and 83%: the sensitivity, specificity, PPV and NPV of GGO were and 43, 84, 40 and 86%, respectively.

CONCLUSION

Symptom of rhinorrhea and GGO predicted viral pneumonia in patients with CAP. The high specificity of rhinorrhea and GGO suggested that these could be useful indicators for empirical antiviral therapy.

Respiratory syncytial virus in hematopoietic cell transplant recipients: factors determining progression to lower respiratory tract disease

BACKGROUND

Respiratory syncytial virus (RSV) lower respiratory tract disease (LRD) is a life-threatening complication in hematopoietic cell transplant (HCT) recipients. Lymphopenia has been associated with an increased risk of progression from upper respiratory tract infection (URI) to LRD.

METHODS

This study retrospectively analyzed the significance of lymphocyte engraftment dynamics, lung function, smoking history, corticosteroids, antiviral treatment, viral subtypes, and RSV-specific neutralizing antibodies for the progression to LRD in 181 HCT recipients with RSV URI.

RESULTS

In multivariable models, smoking history, conditioning with high-dose total body irradiation, and an absolute lymphocyte count (ALC) ≤100/mm(3) at the time of URI onset were significantly associated with disease progression. No progression occurred in patients with ALCs of >1000/mm(3) at URI onset. Lymphocyte engraftment dynamics were similar in progressors and nonprogressors. Pre- and posttransplant donor and posttransplant recipient RSV subtype-specific neutralizing antibody levels, RSV viral subtypes, and corticosteroids also were not significantly associated with LRD progression.

CONCLUSIONS

Host and transplant related factors appear to determine the risk of progression to LRD more than viral factors. Dysfunctional cell-mediated immunity appears to be important in the pathogenesis of progressive RSV disease after HCT. A characterization of RSV-specific T-cell immunity is warranted.

Oral ribavirin therapy for respiratory syncytial virus infections in moderately to severely immunocompromised patients

BACKGROUND

Respiratory syncytial virus (RSV) infections may be fatal in immunocompromised patients. Aerosolized ribavirin is used for treatment, but it is very costly, teratogenic, and inconvenient. We aimed to assess the outcome of oral ribavirin treatment, with or without intravenous immunoglobulin (IVIG), for RSV infections in moderately to severely immunocompromised patients.

METHODS

Medical records of RSV polymerase chain reaction (PCR)-positive patients during 2011-2013 were reviewed retrospectively. Eligible patients were moderately to severely immunocompromised and received oral ribavirin (600-800 mg twice daily) with or without IVIG (500 mg/kg q 48 h) as per protocol.

RESULTS

Of 96 adults with PCR-proven RSV infection, 34 were moderately to severely immunocompromised and received oral ribavirin treatment. The mean age was 56.2 years (range: 18-90); 21 were male. Underlying conditions were hematologic malignancy with or without hematopoietic stem cell transplant (n = 25), lung transplant (n = 3), or receipt of cytotoxic chemotherapy (n = 11). The presenting symptoms were cough (94%), fever (62%), and dyspnea (59%). The most common radiographic findings were patchy and nodular infiltrates and opacities. Of 34 patients, 31 were hospitalized, with 13 admitted to the intensive care unit and 6 required mechanical ventilation. The median absolute lymphocyte count on presentation was 480 cells/mm(3) . RSV pneumonia developed in 24 patients. The median initial duration of oral ribavirin treatment was 10 days (range: 4-11); 4 patients were re-treated. Of 34 patients, 19 received a mean of 2.7 doses of IVIG. Two patients had adverse reactions to ribavirin (hemolytic anemia and lactic acidosis in 1 patient, and altered mental status in another). No patient died from RSV infection. Three patients died from complications of their underlying illness; all others recovered clinically.

CONCLUSIONS

Oral ribavirin with or without IVIG is a well-tolerated treatment for RSV infection in moderately to severely immunocompromised hosts. Comparative prospective studies should ideally be performed to determine if oral ribavirin is the optimal therapy for RSV infection in this patient population.

Virale Infektionen: RNA-Viren

Rhinoviren sind die Haupterreger der sog. Erkältungskrankheiten. Eine wichtige Rolle spielen sie auch als Auslöser von Asthmaattacken.

Es findet eine stete Kozirkulation mehrerer Serotypen statt, im gemäßigten Klima gibt es Herbst-, Winter- und Frühjahrsepidemien, die Übertragung geschieht weit häufiger über infizierte Sekrete als durch Aerosole.

Rhinoviren gehören zu den Picornaviren. Rhinoviren sind sehr kleine Viren mit einem positiven Einzelstrang-RNA-Genom ohne Lipidhülle und daher gegen Detergens enthaltende Desinfektionsmittel sehr resistent. Sie sind empfindlich gegen Umgebungs-pH außerhalb des Bereichs 5,0–7,5.

Zurzeit bilden sie zusammen mit den Enteroviren das Genus Enterovirus der Picornaviren. Serologisch lassen sich über 100 Typen unterscheiden. Kennzeichnend ist die Bindungsfähigkeit an das von den meisten Rhinoviren für die Zelladsorption genützte ICAM-1 (interzelluläres Adhäsionsmolekül).

Nach einer Inkubationszeit von 1–3 Tagen tritt Schnupfen auf, die höchste Viruskonzentration im Nasensekret nach 2–4 Tagen, wiederum nach 2–4 Tagen bei disponierten Patienten auch bronchiale Obstruktion. Es konnte gezeigt werden, dass zu dieser Zeit auch Virus-RNA im Bronchialepithel vorhanden ist. Die postinfektiöse bronchiale Hyperreagibilität korreliert mit der Dauer des Virus-RNA-Nachweises im Nasopharynx. Die Immunität ist im Wesentlichen abhängig von der nur sehr kurzen Anwesenheit sekretorischer spezifischer IgA-Antikörper. Die bei den Serotypen beobachtbare Kreuzreaktivität spiegelt sich nicht in Kreuzimmunität wider.