Clinical implications of respiratory virus infections in solid organ transplant recipients: a prospective study

Respiratory viral infections including COVID-19 in solid organ transplantation

PURPOSE OF REVIEW

Respiratory viral infections are prevalent and contribute to significant morbidity and mortality among solid organ transplant (SOT) recipients. We review updates from literature on respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in the SOT recipient.

RECENT FINDINGS

With the wider availability and use of molecular diagnostic tests, our understanding of the epidemiology and impact of respiratory viruses in the SOT population continues to expand. While considerable attention has been given to the coronavirus disease 2019 (COVID-19) pandemic, the advances in prevention and treatment strategies of SARS-CoV-2 offered valuable insights into the development of new therapeutic options for managing other respiratory viruses in both the general and SOT population.

SUMMARY

Respiratory viruses can present with a diverse range of symptoms in SOT recipients, with potentially associated acute rejection and chronic lung allograft dysfunction in lung transplant recipients. The epidemiology, clinical presentations, diagnostic approaches, and treatment and preventive strategies for clinically significant RNA and DNA respiratory viruses in SOT recipients are reviewed. This review also covers novel antivirals, immunologic therapies, and vaccines in development for various community-acquired respiratory viruses.

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.

Respiratory Syncytial Virus

Human respiratory syncytial virus (RSV) is a negative sense single-stranded RNA virus that can result in epidemics of seasonal respiratory infections. Generally, one of the two genotypes (A and B) predominates in a single season and alternate annually with regional variation. RSV is a known cause of disease and death at both extremes of ages in the pediatric and elderly, as well as immunocompromised populations. The clinical impact of RSV on the hospitalized adults has been recently clarified with the expanded use of multiplex molecular assays. Among adults, RSV can produce a wide range of clinical symptoms due to upper respiratory tract infections potentially leading to severe lower respiratory tract infections, as well as exacerbations of underlying cardiac and lung diseases. While supportive care is the mainstay of therapy, there are currently multiple therapeutic and preventative options under development.

Respiratory Viruses in Solid Organ Transplant Recipients

Solid organ transplantation is often lifesaving, but does carry an increased risk of infection. Respiratory viral infections are one of the most prevalent infections, and are a cause of significant morbidity and mortality, especially among lung transplant recipients. There is also data to suggest an association with acute rejection and chronic lung allograft dysfunction in lung transplant recipients. Respiratory viral infections can appear at any time post-transplant and are usually acquired in the community. All respiratory viral infections share similar clinical manifestations and are all currently diagnosed using nucleic acid testing. Influenza has good treatment options and prevention strategies, although these are hampered by resistance to neuraminidase inhibitors and lower vaccine immunogenicity in the transplant population. Other respiratory viruses, unfortunately, have limited treatments and preventive methods. This review summarizes the epidemiology, clinical manifestations, therapies and preventive measures for clinically significant RNA and DNA respiratory viruses, with the exception of SARS-CoV-2. This area is fast evolving and hopefully the coming decades will bring us new antivirals, immunologic treatments and vaccines.

The Magnitude and Functionality of SARS-CoV-2 Reactive Cellular and Humoral Immunity in Transplant Population Is Similar to the General Population Despite Immunosuppression

BACKGROUND

The ability of transplant (Tx) patients to generate a protective antiviral response under immunosuppression is pivotal in COVID-19 infection. However, analysis of immunity against SARS-CoV-2 is currently lacking.

METHODS

Here, we analyzed T cell immunity directed against SARS-CoV-2 spike-, membrane-, and nucleocapsid-protein by flow cytometry and spike-specific neutralizing antibodies in 10 Tx in comparison to 26 nonimmunosuppressed (non-Tx) COVID-19 patients.

RESULTS

Tx patients (7 renal, 1 lung, and 2 combined pancreas-kidney Txs) were recruited in this study during the acute phase of COVID-19 with a median time after SARS-CoV-2-positivity of 3 and 4 d for non-Tx and Tx patients, respectively. Despite immunosuppression, we detected antiviral CD4+ T cell-response in 90% of Tx patients. SARS-CoV-2-reactive CD4+ T cells produced multiple proinflammatory cytokines, indicating their potential protective capacity. Neutralizing antibody titers did not differ between groups. SARS-CoV-2-reactive CD8+ T cells targeting membrane- and spike-protein were lower in Tx patients, albeit without statistical significance. However, frequencies of anti-nucleocapsid-protein-reactive, and anti-SARS-CoV-2 polyfunctional CD8+ T cells, were similar between patient cohorts. Tx patients showed features of a prematurely aged adaptive immune system, but equal frequencies of SARS-CoV-2-reactive memory T cells.

CONCLUSIONS

In conclusion, a polyfunctional T cell immunity directed against SARS-CoV-2 proteins as well as neutralizing antibodies can be generated in Tx patients despite immunosuppression. In comparison to nonimmunosuppressed patients, no differences in humoral and cellular antiviral-immunity were found. Our data presenting the ability to generate SARS-CoV-2-specific immunity in immunosuppressed patients have implications for the handling of SARS-CoV-2-infected Tx patients and raise hopes for effective vaccination in this cohort.

Burden, epidemiology, and outcomes of microbiologically confirmed respiratory viral infections in solid organ transplant recipients: a nationwide, multi-season prospective cohort study

Solid organ transplant (SOT) recipients are exposed to respiratory viral infection (RVI) during seasonal epidemics; however, the associated burden of disease has not been fully characterized. We describe the epidemiology and outcomes of RVI in a cohort enrolling 3294 consecutive patients undergoing SOT from May 2008 to December 2015 in Switzerland. Patient and allograft outcomes, and RVI diagnosed during routine clinical practice were prospectively collected. Median follow-up was 3.4 years (interquartile range 1.61-5.56). Six hundred ninety-six RVIs were diagnosed in 151/334 (45%) lung and 265/2960 (9%) non-lung transplant recipients. Cumulative incidence was 60% (95% confidence interval [CI] 53%-69%) in lung and 12% (95% CI 11%-14%) in non-lung transplant recipients. RVI led to 17.9 (95% CI 15.7-20.5) hospital admissions per 1000 patient-years. Intensive care unit admission was required in 4% (27/691) of cases. Thirty-day all-cause case fatality rate was 0.9% (6/696). Using proportional hazard models we found that RVI (adjusted hazard ratio [aHR] 2.45; 95% CI 1.62-3.73), lower respiratory tract RVI (aHR 3.45; 95% CI 2.15-5.52), and influenza (aHR 3.57; 95% CI 1.75-7.26) were associated with graft failure or death. In this cohort of SOT recipients, RVI caused important morbidity and may affect long-term outcomes, underlying the need for improved preventive strategies.

Clinical manifestations and outcomes of coronavirus disease-19 in heart transplant recipients: a multicentre case series with a systematic review and meta-analysis

Available data on clinical presentation and mortality of coronavirus disease‐2019 (COVID‐19) in heart transplant (HT) recipients remain limited. We report a case series of laboratory‐confirmed COVID‐19 in 39 HT recipients from 3 French heart transplant centres (mean age 54.4 ± 14.8 years; 66.7% males). Hospital admission was required for 35 (89.7%) cases including 14/39 (35.9%) cases being admitted in intensive care unit. Immunosuppressive medications were reduced or discontinued in 74.4% of the patients. After a median follow‐up of 54 (19–80) days, death and death or need for mechanical ventilation occurred in 25.6% and 33.3% of patients, respectively. Elevated C‐reactive protein and lung involvement ≥50% on chest computed tomography (CT) at admission were associated with an increased risk of death or need for mechanical ventilation. Mortality rate from March to June in the entire 3‐centre HT recipient cohort was 56% higher in 2020 compared to the time‐matched 2019 cohort (2% vs. 1.28%, P = 0.15). In a meta‐analysis including 4 studies, pre‐existing diabetes mellitus (OR 3.60, 95% CI 1.43–9.06, I² = 0%, P = 0.006) and chronic kidney disease stage III or higher (OR 3.79, 95% CI 1.39–10.31, I² = 0%, P = 0.009) were associated with increased mortality. These findings highlight the aggressive clinical course of COVID‐19 in HT recipients.

Risk Classification for Respiratory Viral Infections in Adult Solid Organ Transplantation Recipients

INTRODUCTION

Molecular testing such as nasopharyngeal viral polymerase chain reaction (PCR) (NVP) is available now in most hospitals and widely used to identify respiratory viral infections (RVIs) in solid organ transplantation (SOT) recipients.

MATERIALS AND METHODS

A retrospective multicenter study at 8 hospitals from March 1, 2016, to April 30, 2019. We included all adult SOT recipients who were admitted to the hospitals and had their first NVP post transplantation.

RESULTS

A total of 102 adult SOT recipients were enrolled. NVP test was positive in 33 (32.4%) SOT recipients and negative in 69 (67.6%). Median age was more than 60 years old with female predominance in both groups. The majority of patients who had positive NVP were hospitalized either in fall or winter seasons (91%). RVI symptoms were documented in about 73% of the positive NVP group. Rhinovirus was the most common identified virus (48.4%). On logistic regression analysis, clinical presentation in fall or winter seasons, presenting with upper respiratory infection (URI) symptoms and taking prednisone ≥10 mg/d were significantly associated with positive NVP. This model classified patients into 3 categories of risk for RVIs-low (none of the variables), 0%; intermediate (1 variable), 6.5%; and high (≥2 variables), 55.4% with P < .001 for all predictors.

CONCLUSION

SOT recipients who are taking prednisone (≥10 mg) and have URI symptoms in fall or winter seasons are more likely to have RVIs.

Respiratory syncytial virus infection in adults

Human respiratory syncytial virus (RSV) belongs to the recently defined Pneumoviridae family, Orthopneumovirus genus. It is a negative sense, single stranded RNA virus that results in epidemics of respiratory infections that typically peak in the winter in temperate climates and during the rainy season in tropical climates. Generally, one of the two genotypes (A and B) predominates in a single season, alternating annually, although regional variation occurs. RSV is a cause of disease and death in children, older people, and immunocompromised patients, and its clinical effect on adults admitted to hospital is clarified with expanded use of multiplex molecular assays. Among adults, RSV produces a wide range of clinical symptoms including upper respiratory tract infections, severe lower respiratory tract infections, and exacerbations of underlying disease. Here we discuss the latest evidence on the burden of RSV related disease in adults, especially in those with immunocompromise or other comorbidities. We review current therapeutic and prevention options, as well as those in development.

RNA respiratory viral infections in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of RNA respiratory viral infections in the pre‐ and post‐transplant period. Viruses reviewed include influenza, respiratory syncytial virus (RSV), parainfluenza, rhinovirus, human metapneumovirus (hMPV), and coronavirus. Diagnosis is by nucleic acid testing due to improved sensitivity, specificity, broad range of detection of viral pathogens, automatization, and turnaround time. Respiratory viral infections may be associated with acute rejection and chronic lung allograft dysfunction in lung transplant recipients. The cornerstone of influenza prevention is annual vaccination and in some cases antiviral prophylaxis. Treatment with neuraminidase inhibitors and other antivirals is reviewed. Prevention of RSV is limited to prophylaxis with palivizumab in select children. Therapy of RSV upper or lower tract disease is controversial but may include oral or aerosolized ribavirin in some populations. There are no approved vaccines or licensed antivirals for parainfluenza, rhinovirus, hMPV, and coronavirus. Potential management strategies for these viruses are given. Future studies should include prospective trials using contemporary molecular diagnostics to understand the true epidemiology, clinical spectrum, and long‐term consequences of respiratory viruses as well as to define preventative and therapeutic measures.

Respiratory Viral Infections in Transplant Recipients

Respiratory viral infections (RVIs) are common among the general population; however, these often mild viral illnesses can lead to serious morbidity and mortality among recipients of hematopoietic stem cell and solid organ transplantation. The disease spectrum ranges from asymptomatic or mild infections to life-threatening lower respiratory tract infection or long-term airflow obstruction syndromes. Progression to lower respiratory tract infection or to respiratory failure is determined by the intrinsic virulence of the specific viral pathogen as well as various host factors, including the type of transplantation, status of the host’s immune dysfunction, the underlying disease, and other comorbidities. This chapter focuses on the epidemiology, clinical manifestations, diagnosis, and management of RVIs in this susceptible population and includes respiratory syncytial virus, parainfluenza virus, human metapneumovirus, influenza virus, human coronavirus, and human rhinovirus. The optimal management of these infections is limited by the overall paucity of available treatment, highlighting the need for new antiviral drug or immunotherapies.

Respiratory Tract Infections: Sinusitis, Bronchitis, and Pneumonia

Solid organ and hematopoietic stem cell transplant recipients are at increased risk of upper and lower respiratory tract infections. While these infections are frequently encountered in the general population, the spectrum of their clinical presentation including morbidity and mortality is increased in patients undergoing transplantation procedures. Impaired innate and adaptive immunity, potential anatomical abnormalities resulting from extensive surgical procedures, presences of indwelling medical devices, and increased healthcare exposure put transplant recipients at particularly high risk for respiratory tract disease. Infections of the respiratory tract can be divided into those affecting the paranasal sinuses, the upper airways such as bronchitis and tracheobronchitis, and the lower airways like pneumonia. Each of these clinical syndromes can further be classified based on their chronicity, acute vs. chronic; their setting, community vs. nosocomial; and the etiology such as bacteria, viruses, fungi, and rarely parasites. It is also important to realize that such immunologically vulnerable patients are at risk for polymicrobial infection that may present concurrently or in a sequential, consecutive fashion. This chapter reviews the common respiratory tract infections affecting transplant recipients with particular attention directed toward epidemiological risk factors, clinical presentations, diagnostic strategies, and common pathogens. Specific causes of opportunistic pneumonias are also reviewed.

Post-transplant Viral Respiratory Infections in the Older Patient: Epidemiology, Diagnosis, and Management

Organ and stem cell transplantation has been one of the greatest advances in modern medicine, and is the primary treatment modality for many end-stage diseases. As our population ages, so do the transplant recipients, and with that comes many new challenges. Respiratory viruses have been a large contributor to the mortality and morbidity of solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. Respiratory viruses are generally a long-term complication of transplantation and primarily acquired in the community. With the emergence of molecular methods, newer respiratory viruses are being detected. Respiratory viruses appear to cause severe disease in the older transplant population. Influenza vaccine remains the mainstay of prevention in transplant recipients, although immunogenicity of current vaccines is suboptimal. Limited therapies are available for other respiratory viruses. The next decade will likely bring newer antivirals and vaccines to the forefront. Our goal is to provide the most up to date knowledge of respiratory viral infections in our aging transplant population.

Update in the treatment of non-influenza respiratory virus infection in solid organ transplant recipients

INTRODUCTION

Despite the improved outcomes in solid organ transplantation with regard to prevention of rejection and increased patient and graft survival, infection remains a common cause of morbidity and mortality. Respiratory viruses are a frequent and potentially serious cause of infection after solid organ transplantation. Furthermore, clinical manifestations of respiratory virus infection (RVI) may be more severe and unusual in solid organ transplant recipients (SOTRs) compared with the non-immunocompromised population. Areas covered: This article reviews the non-influenza RVIs that are commonly encountered in SOTRs. Epidemiologic and clinical characteristics are highlighted and available treatment options are discussed. Expert opinion: New diagnostic tools, particularly rapid molecular assays, have expanded the ability to identify specific RVI pathogens in SOTRs. This is not only useful from a treatment standpoint but also to guide infection control practices. More data are needed on RVIs in the solid organ transplant population, particularly regarding their effect on rejection and graft dysfunction. There is also a need for new antiviral agents active against these infections as well as markers that can identify which patients would most benefit from treatment.

Epidemiology and Immediate Indirect Effects of Respiratory Viruses in Lung Transplant Recipients: A 5-Year Prospective Study

The epidemiology of respiratory viruses (RVs) in lung transplant recipients (LTRs) and the relationship of RVs to lung function, acute rejection (AR) and opportunistic infections in these patients are not well known. We performed a prospective cohort study (2009-2014) by collecting nasopharyngeal swabs (NPSs) from asymptomatic LTRs during seasonal changes and from LTRs with upper respiratory tract infectious disease (URTID), lower respiratory tract infectious disease (LRTID) and AR. NPSs were analyzed by multiplex polymerase chain reaction. Overall, 1094 NPSs were collected from 98 patients with a 23.6% positivity rate and mean follow-up of 3.4 years (interquartile range 2.5-4.0 years). Approximately half of URTIDs (47 of 97, 48.5%) and tracheobronchitis cases (22 of 56, 39.3%) were caused by picornavirus, whereas pneumonia was caused mainly by paramyxovirus (four of nine, 44.4%) and influenza (two of nine, 22.2%). In LTRs with LRTID, lung function changed significantly at 1 mo (p = 0.03) and 3 mo (p = 0.04). In a nested case-control analysis, AR was associated with RVs (hazard ratio [HR] 6.54), Pseudomonas aeruginosa was associated with LRTID (HR 8.54), and cytomegalovirus (CMV) replication or disease was associated with URTID (HR 2.53) in the previous 3 mo. There was no association between RVs and Aspergillus spp. colonization or infection (HR 0.71). In conclusion, we documented a high incidence of RV infections in LTRs. LRTID produced significant lung function abnormalities. Associations were observed between AR and RVs, between P. aeruginosa colonization or infection and LRTID, and between CMV replication or disease and URTID.

Overview of Infections in the Immunocompromised Host

Understanding the components of the immune system that contribute to host defense against infection is key to recognizing infections that are more likely to occur in an immunocompromised patient. In this review, we discuss the integrated system of physical barriers and of innate and adaptive immunity that contributes to host defense. Specific defects in the components of this system that predispose to particular infections are presented. This is followed by a review of primary immunodeficiency diseases and secondary immunodeficiencies, the latter of which develop because of a specific illness or condition or are treatment-related. The effects of treatment for neoplasia, autoimmune diseases, solid organ and stem cell transplants on host defenses are reviewed and associated with susceptibility to particular infections. In conclusion, an approach to laboratory screening for a suspected immunodeficiency is presented. Knowledge of which host defects predispose to specific infections allows clinicians to prevent, diagnose, and manage infections in their immunocompromised patients most effectively.

Cost-effectiveness analysis of quadrivalent influenza vaccine in Spain

Influenza has a major impact on healthcare systems and society, but can be prevented using vaccination. The World Health Organization (WHO) currently recommends that influenza vaccines should include at least two virus A and one virus B lineage (trivalent vaccine; TIV). A new quadrivalent vaccine (QIV), which includes an additional B virus strain, received regulatory approval and is now recommended by several countries. The present study estimates the cost-effectiveness of replacing TIVs with QIV for risk groups and elderly population in Spain. A static, lifetime, multi-cohort Markov model with a one-year cycle time was adapted to assess the costs and health outcomes associated with a switch from TIV to QIV. The model followed a cohort vaccinated each year according to health authority recommendations, for the duration of their lives. National epidemiological data allowed the determination of whether the B strain included in TIVs matched the circulating one. Societal perspective was considered, costs and outcomes were discounted at 3% and one-way and probabilistic sensitivity analyses were performed. Compared to TIVs, QIV reduced more influenza cases and influenza-related complications and deaths during periods of B-mismatch strains in the TIV. The incremental cost-effectiveness ratio (ICER) was 8,748€/quality-adjusted life year (QALY). One-way sensitivity analysis showed mismatch with the B lineage included in the TIV was the main driver for ICER. Probabilistic sensitivity analysis shows ICER below 30,000€/QALY in 96% of simulations. Replacing TIVs with QIV in Spain could improve influenza prevention by avoiding B virus mismatch and provide a cost-effective healthcare intervention.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

DAMPs and influenza virus infection in ageing

Influenza A virus (IAV) is a serious global health problem worldwide due to frequent and severe outbreaks. IAV causes significant morbidity and mortality in the elderly population, due to the ineffectiveness of the vaccine and the alteration of T cell immunity with ageing. The cellular and molecular link between ageing and virus infection is unclear and it is possible that damage associated molecular patterns (DAMPs) may play a role in the raised severity and susceptibility of virus infections in the elderly. DAMPs which are released from damaged cells following activation, injury or cell death can activate the immune response through the stimulation of the inflammasome through several types of receptors found on the plasma membrane, inside endosomes after endocytosis as well as in the cytosol. In this review, the detriment in the immune system during ageing and the links between influenza virus infection and ageing will be discussed. In addition, the role of DAMPs such as HMGB1 and S100/Annexin in ageing, and the enhanced morbidity and mortality to severe influenza infection in ageing will be highlighted.

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.

Adult patients with respiratory syncytial virus infection: impact of solid organ and hematopoietic stem cell transplantation on outcomes

BACKGROUND

Respiratory syncytial virus (RSV) is a common community-acquired pathogen responsible for a substantial disease burden in adults. We investigated the outcomes after RSV infection in hospitalized adults over a 3-year period.

METHODS

This single-center, retrospective study identified 174 patients hospitalized with RSV upper or lower respiratory tract infection (LRTI) between January 1, 2009 and June 30, 2012. Clinical data were extracted from medical records. The primary outcome analyzed was all-cause mortality, defined as death during the index hospital admission. Subjects were divided into 3 groups for comparison: hematopoietic stem cell transplant (HSCT) patients, solid organ transplant (SOT) patients, and non-transplant patients.

RESULTS

In our study, 41/174 (23.6%) were HSCT recipients and 28/174 (16.1%) were SOT recipients. Twelve of 174 (6.9%) died. Death occurred in 2/41 (4.9%) HSCT and 3/28 (10.7%) SOT recipients, compared to 7/106 (6.6%) non-transplant patients. When compared to the non-transplant cohort, HSCT and SOT were not found to be significant risk factors for mortality (P = 0.685 and 0.645, respectively). In multivariate logistic regression, age >60 was associated with mortality (P = 0.019), while lymphopenia on admission trended toward an association with death (P = 0.054). HSCT patients were less likely to be admitted to an intensive care unit (odds ratio [OR] 0.26, P = 0.04), but were significantly more likely to receive ribavirin therapy (OR 11.62, P < 0.0001).

CONCLUSION

Adults hospitalized with RSV LRTI are at significant risk of mortality, and this risk may be increased in patients age >60 or with lymphopenia on admission. This study did not identify any significant increased mortality or morbidity associated with RSV infection in immune suppressed transplant recipients vs. patients who had not received a transplant.

Randomized, double-blind comparison of standard-dose vs. high-dose trivalent inactivated influenza vaccine in pediatric solid organ transplant patients

Children who have undergone SOT mount a lower immune response after vaccination with TIV compared to healthy controls. HD or SD TIV in pediatric SOT was given to subjects 3-17 yr and at least six months post-transplant. Subjects were randomized 2:1 to receive either the HD (60 μg) or the SD (15 μg) TIV. Local and systemic reactions were solicited after each vaccination, and immune responses were measured before and after each vaccination. Thirty-eight subjects were enrolled. Mean age was 11.25 yr; 68% male, 45% renal, 26% heart, 21% liver, 5% lung, and 5% intestinal. Twenty-three subjects were given HD and 15 SD TIV. The median time since transplant receipt was 2.2 yr. No severe AEs or rejection was attributed to vaccination. The HD group reported more tenderness and local reactions, fatigue, and body ache when compared to the SD cohort, but these were considered mild and resolved within three days. Subjects in the HD group demonstrated a higher percentage of four-fold titer rise to H3N2 compared to the SD group. HD influenza vaccine was well tolerated and may have increased immunogenicity. A phase 2 trial is needed to confirm.

Rhinosinusitis in hematopoietic stem cell-transplanted patients: influence of nasosinus mucosal abnormalities?

Introduction

Rhinosinusitis is characterized by inflammation extending from the mucosa of the nasal cavity into the paranasal sinuses. There are some aggravating features, such as immunosuppression, that can cause the nasal mucosal inflammation to linger for a long period, resulting in chronic or recurrent episodes. Such immunosuppression is the major feature of patients undergoing a hematopoietic stem cell transplant (HSCT); rhinosinusitis prevalence is higher in this group compared to immunocompetent patients. Nasal epithelial abnormalities have been described in, and may have some influence over, recurrent sinus infections among those patients. However, it is not clear whether rhinosinusitis can trigger mucosal abnormalities or whether a preexisting vulnerability for sinusitis recurrence is more likely. The objective of the study was to verify the influence of rhinosinusitis on nasal epithelial damage in patients undergoing hematopoietic stem cell transplantation.

Method

A total of 30 allogeneic HSCT patients were divided into two groups: 24 patients with chronic or recurrent rhinosinusitis and 6 patients without rhinosinusitis. These patients underwent a biopsy of the uncinate process that was analyzed by transmission electron microscopy and optical microscopy.

Results

The nasal mucosa analysis by optical microscopy showed no significant abnormalities. The ciliary orientation was obviously normal in the transplanted patients without rhinosinusitis. There was a trend toward a difference in the amount of cilia (decreased) and the primary modification of the ultrastructure of transplanted patients with rhinosinusitis.

Conclusion

HSCT patients, with and without rhinosinusitis, showed no significant histological abnormalities, except for ciliary disorientation and a possible decrease in ciliary and ultrastructural abnormalities in HSCT patients with rhinosinusitis.

A patient self-collection method for longitudinal monitoring of respiratory virus infection in solid organ transplant recipients

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We evaluate self-collection of nasal swabs using a longitudinal study design.

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Self-collected nasal swabs are feasible in solid organ transplant recipients.

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Self-collected nasal swabs are acceptable to solid organ transplant recipients.

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Self-collected nasal swabs are convenient to longitudinally study respiratory viruses.

Background

Methods for the longitudinal study of respiratory virus infections are cumbersome and limit our understanding of the natural history of these infections in solid organ transplant (SOT) recipients.

Objectives

To assess the feasibility and patient acceptability of self-collected foam nasal swabs for detection of respiratory viruses in SOT recipients and to define the virologic and clinical course.

Study design

We prospectively monitored the course of symptomatic respiratory virus infection in 18 SOT patients (14 lung, 3 liver, and 1 kidney) using patient self-collected swabs.

Results

The initial study sample was positive in 15 patients with the following respiratory viruses: rhinovirus (6), metapneumovirus (1), coronavirus (2), respiratory syncytial virus (2), parainfluenza virus (2), and influenza A virus (2). One hundred four weekly self-collected nasal swabs were obtained, with a median of 4 samples per patient (range 1–17). Median duration of viral detection was 21 days (range 4–77 days). Additional new respiratory viruses detected during follow-up of these 15 patients included rhinovirus (3), metapneumovirus (2), coronavirus (1), respiratory syncytial virus (1), parainfluenza virus (1), and adenovirus (1). Specimen collection compliance was good; 16/18 (89%) patients collected all required specimens and 79/86 (92%) follow-up specimens were obtained within the 7 ± 3 day protocol-defined window. All participants agreed or strongly agreed that the procedure was comfortable, simple, and 13/14 (93%) were willing to participate in future studies using this procedure.

Conclusion

Self-collected nasal swabs provide a convenient, feasible, and patient-acceptable methodology for longitudinal monitoring of upper respiratory virus infection in SOT recipients.

Mucosal cysts of the maxillary sinus in solid organ transplant population: computerised tomography follow-up results

BACKGROUND

The clinical significance of maxillary sinus mucosal cysts in liver and kidney transplant recipients remains unclear.

AIM

To investigate the course of maxillary mucosal cysts in liver and kidney transplantation patients.

STUDY DESIGN

Retrospective clinical study.

METHODS

Paranasal sinus computed tomography scans of 169 renal and 43 hepatic transplant recipients were reviewed. The incidence, size and growth characteristics of maxillary mucosal cysts in the renal and hepatic transplant population were noted.

RESULTS

Overall incidence of maxillary sinus mucosal cyst in transplantation patients was found to be 24.5%, with a male to female ratio of 2:1 (p<0.05). Follow-up views of 26 patients showed that the size of the cysts increased in 19, decreased in 4, and remained the same in 3 patients. Mean growth rate of the cysts was calculated to be 6.30 ± 7.02 mm(2) per month. Most of the cysts were located on the inferior wall of the maxillary sinus.

CONCLUSION

Incidence of the maxillary mucosal cysts in renal and hepatic transplant recipients does not differ from general population, but these cysts have a greater tendency to grow. Specific measures are not needed for isolated, asymptomatic maxillary mucosal cysts in transplant populations.

[Nosocomial infection in patients receiving a solid organ transplant or haematopoietic stem cell transplant]

Bacterial infections are the most common infections in solid organ transplant recipients. These infections occur mainly in the first month after transplantation and are hospital-acquired. Nosocomial infections cause significant morbidity and are the most common cause of mortality in this early period of transplantation. These infections are caused by multi-drug resistant (MDR) microorganisms, mainly Gram-negative enterobacteria, non-fermentative Gram-negative bacilli, enterococci, and staphylococci. The patients at risk of developing nosocomial bacterial infections are those previously colonized with MDR bacteria while on the transplant waiting list. Intravascular catheters, the urinary tract, the lungs, and surgical wounds are the most frequent sources of infection. Preventive measures are the same as those applied in non-immunocompromised, hospitalized patients except in patients at high risk for developing fungal infection. These patients need antifungal therapy during their hospitalization, and for preventing some bacterial infections in the early transplant period, patients need vaccinations on the waiting list according to the current recommendations. Although morbidity and mortality related to infectious diseases have decreased during the last few years in haematopoietic stem cell transplant recipients, they are still one of the most important complications in this population. Furthermore, as occurs in the general population, the incidence of nosocomial infections has increased during the different phases of transplantation. It is difficult to establish general preventive measures in these patients, as there are many risk factors conditioning these infections. Firstly, they undergo multiple antibiotic treatments and interventions; secondly, there is a wide variability in the degree of neutropenia and immunosuppression among patients, and finally they combine hospital and home stay during the transplant process. However, some simple measures could be implemented to improve the current situation.

Risks and prevention of severe RS virus infection among children with immunodeficiency and Down's syndrome

By the age of two years, almost all infants are infected with the Respiratory syncytial virus (RSV). One of the main causes of hospitalizations for bronchiolitis and pneumonia at this age is RSV infection. In addition to well-known risks for severe RSV disease, such as prematurity, bronchopulmonary dysplasia and congenital heart disease, immunodeficiencies, chromosomal abnormalities such as Down's syndrome or neuromuscular diseases have also been identified as risks. While the medical needs for RSV prevention in these risk groups are high, clinical evidence to support this is limited. Palivizumab was recently approved in Japan for prophylaxis in children with immunodeficiency or Down's syndrome. A clinical guidance protocol for the prevention of RSV infection using Palivizumab in these risk groups is provided here on the basis of a review of the available literature and on expert opinion. Thus, the present article reviews the published literature related to RSV infections in infants and children with immunodeficiencies or Down's syndrome in order to outline the risks, pathology and physiology of severe RSV disease in these patient groups. The purpose of this article is to facilitate understanding of the medical scientific bases for the clinical guidance.

Lower respiratory tract viral infections in pediatric abdominal organ transplant recipients: a single hospital inpatient cohort study

Respiratory viral infections are a major cause of morbidity and mortality in solid organ transplant recipients. Early detection of a viral etiology of a LRTI in a febrile transplant recipient can theoretically reduce the use of antibiotics, trigger modification of immunosuppression and prompt appropriate isolation procedures to reduce nosocomial infections. We retrospectively evaluated pediatric abdominal organ transplant recipients hospitalized with respiratory illnesses to determine the viral pathogens identified by various methods including multiplex RT-PCR performed on nasopharyngeal or endotracheal aspirates. Among 30 symptomatic subjects (median age, 2.5 yr) evaluated using this methodology, 25 (83%) were positive for at least one virus. Rhinovirus was the most frequently identified virus (14 subjects). RSV was identified in five subjects with associated mortality of 40%. Parainfluenza, influenza, metapneumovirus, and adenovirus were also identified. This study indicates that rhinovirus is a significant cause of morbidity in this single center cohort of pediatric abdominal organ transplant recipients.

Prolonged influenza virus shedding and emergence of antiviral resistance in immunocompromised patients and ferrets

Immunocompromised individuals tend to suffer from influenza longer with more serious complications than otherwise healthy patients. Little is known about the impact of prolonged infection and the efficacy of antiviral therapy in these patients. Among all 189 influenza A virus infected immunocompromised patients admitted to ErasmusMC, 71 were hospitalized, since the start of the 2009 H1N1 pandemic. We identified 11 (15%) cases with prolonged 2009 pandemic virus replication (longer than 14 days), despite antiviral therapy. In 5 out of these 11 (45%) cases oseltamivir resistant H275Y viruses emerged. Given the inherent difficulties in studying antiviral efficacy in immunocompromised patients, we have infected immunocompromised ferrets with either wild-type, or oseltamivir-resistant (H275Y) 2009 pandemic virus. All ferrets showed prolonged virus shedding. In wild-type virus infected animals treated with oseltamivir, H275Y resistant variants emerged within a week after infection. Unexpectedly, oseltamivir therapy still proved to be partially protective in animals infected with resistant virus. Immunocompromised ferrets offer an attractive alternative to study efficacy of novel antiviral therapies.

Immunocompromised patients, such as transplant recipients on immune suppressive therapy, are a substantial and gradually expanding patient group. Upon influenza virus infection, these patients clear the virus less efficiently and are more likely to develop severe pneumonia than immunocompetent individuals. Existing antiviral strategies are far from satisfactory for this patient group, as they show limited effectiveness with frequent emergence of antiviral resistance. For ethical and practical reasons antiviral efficacy studies are hard to conduct in these patients. Therefore, we developed an immunocompromised ferret, mimicking an immune suppressive regimen used for solid organ transplant recipients. Upon infection with 2009 pandemic influenza A/H1N1 virus these animals, like immunocompromised patients, develop severe respiratory disease with prolonged virus excretion. Interestingly, all immunocompromised ferrets on oseltamivir therapy excreted oseltamivir resistant viruses (H275Y) within one week after start of treatment. Furthermore, high dose oseltamivir therapy still proved to be partially effective against these oseltamivir resistant viruses. These immunocompromised ferrets provide a useful tool in the development of novel antiviral approaches for immunocompromised patients suffering from influenza.

Management of influenza infection in solid-organ transplant recipients: consensus statement of the Group for the Study of Infection in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Network for Research in Infectious Diseases (REIPI)

BACKGROUND

Solid organ transplant (SOT) recipients are at greater risk than the general population for complications and mortality from influenza infection.

METHODS

Researchers and clinicians with experience in SOT infections have developed this consensus document in collaboration with several Spanish scientific societies and study networks related to transplant management. We conducted a systematic review to assess the management and prevention of influenza infection in SOT recipients. Evidence levels based on the available literature are given for each recommendation. This article was written in accordance with international recommendations on consensus statements and the recommendations of the Appraisal of Guidelines for Research and Evaluation II (AGREE II).

RESULTS

Recommendations are provided on the procurement of organs from donors with suspected or confirmed influenza infection. We highlight the importance of the possibility of influenza infection in any SOT recipient presenting upper or lower respiratory symptoms, including pneumonia. The importance of early antiviral treatment of SOT recipients with suspected or confirmed influenza infection and the necessity of annual influenza vaccination are emphasized. The microbiological techniques for diagnosis of influenza infection are reviewed. Guidelines for the use of antiviral prophylaxis in inpatients and outpatients are provided. Recommendations for household contacts of SOT recipients with influenza infection and health care workers in close contact with transplant patients are also included. Finally antiviral dose adjustment guidelines are presented for cases of impaired renal function and for pediatric populations.

CONCLUSIONS

The latest scientific information available regarding influenza infection in the context of SOT is incorporated into this document.

The impact of RSV, adenovirus, influenza, and parainfluenza infection in pediatric patients receiving stem cell transplant, solid organ transplant, or cancer chemotherapy

RVIs are a significant cause of morbidity and mortality in immunocompromised children. We analyzed the characteristics and outcomes of infection by four respiratory viruses (RSV, adenovirus, influenza, and parainfluenza) treated at a pediatric tertiary care hospital in a retrospective cohort of patients who had received cancer chemotherapy, hematopoietic stem cell, or SOT. A total of 208 infections were studied among 166 unique patients over a time period of 1993-2006 for transplant recipients, and 2000-2005 for patients with cancer. RSV was the most common respiratory virus identified. There were 17 (10% of all patients) deaths overall, of which 12 were at least partly attributed to the presence of a RVI. In multivariate models, LRT symptoms in the absence of upper respiratory symptoms on presentation (OR 10.2 [2.3, 45.7], p = 0.002) and adenoviral infection (OR 3.7 [1.1, 12.6], p = 0.034) were significantly associated with poor outcome, defined as death or disability related to RVI. All of the deaths occurred in patients who had received either solid organ or HSCT. There were no infections resulting in death or disability in the cancer chemotherapy group.

Efficacy of oral ribavirin in hematologic disease patients with paramyxovirus infection: analytic strategy using propensity scores

Few antiviral agents are available for treating paramyxovirus infections, such as those involving respiratory syncytial virus (RSV), parainfluenza virus (PIV), and human metapneumovirus (hMPV). We evaluated the effect of oral ribavirin on clinical outcomes of paramyxovirus infections in patients with hematological diseases. All adult patients with paramyxovirus were retrospectively reviewed over a 2-year period. Patients who received oral ribavirin were compared to those who received supportive care without ribavirin therapy. A propensity-matched case-control study and a logistic regression model with inverse probability of treatment weighting (IPTW) were performed to reduce the effect of selection bias in assignment for oral ribavirin therapy. A total of 145 patients, including 64 (44%) with PIV, 60 (41%) with RSV, and 21 (15%) with hMPV, were analyzed. Of these 145 patients, 114 (78%) received oral ribavirin and the remaining 31 (21%) constituted the nonribavirin group. Thirty-day mortality and underlying respiratory death rates were 31% (35/114) and 12% (14/114), respectively, for the oral ribavirin group versus 19% (6/31) and 16% (5/31), respectively, for the nonribavirin group (P = 0.21 and P = 0.56). In the case-control study, the 30-day mortality rate in the ribavirin group was 24% (5/21) versus 19% (4/21) in the nonribavirin group (P = 0.71). In addition, the logistic regression model with IPTW revealed no significant difference in 30-day mortality (adjusted hazard ratio of 1.3; 95% confidence interval [95% CI] of 0.3 to 5.8) between the two groups. Steroid use (adjusted odds ratio, 5.67; P = 0.01) and upper respiratory tract infection (adjusted odds ratio, 0.07; P = 0.001) was independently associated with mortality. Our data suggest that oral ribavirin therapy may not improve clinical outcomes in hematologic disease patients infected with paramyxovirus.

Emerging viral diseases in kidney transplant recipients

Viruses are the most important cause of infections and a major source of mortality in Kidney Transplant Recipients (KTRs). These patients may acquire viral infections through exogenous routes including community exposure, donor organs, and blood products or by endogenous reactivation of latent viruses. Beside major opportunistic infections due to CMV and EBV and viral hepatitis B and C, several viral diseases have recently emerged in KTRs. New medical practices or technologies, implementation of new diagnostic tools, and improved medical information have contributed to the emergence of these viral diseases in this special population. The purpose of this review is to summarize the current knowledge on emerging viral diseases and newly discovered viruses in KTRs over the last two decades. We identified viruses in the field of KT that had shown the greatest increase in numbers of citations in the NCBI PubMed database. BKV was the most cited in the literature and linked to an emerging disease that represents a great clinical concern in KTRs. HHV-8, PVB19, WNV, JCV, H1N1 influenza virus A, HEV, and GB virus were the main other emerging viruses. Excluding HHV8, newly discovered viruses have been infrequently linked to clinical diseases in KTRs. Nonetheless, pathogenicity can emerge long after the discovery of the causative agent, as has been the case for BKV. Overall, antiviral treatments are very limited, and reducing immunosuppressive therapy remains the cornerstone of management.

Molecular detection of respiratory viruses in immunocopromised ICU patients: incidence and meaning

Purpose

Prospective single-center study to assess the sensitivity and clinical relevance of molecular testing for respiratory viruses in critically ill immunocompromised patients with acute respiratory failure (ARF).

Methods

100 consecutive critically ill immunocompromised patients with ARF in 2007–2009. Among them, 65 had hematologic malignancies (including 14 hematopoietic stem cell transplant recipients), 22 had iatrogenic immunosuppression, and 13 had solid malignancies. A multiplex molecular assay (MMA) was added to the usual battery of tests performed to look for causes of ARF.

Results

Nasopharyngeal aspirates and/or bronchoalveolar lavage fluid were tested for respiratory viruses using both the MMA and immunofluorescence. A virus was detected in 47 (47%) patients using the MMA and 8 (8%) patients using immunofluorescence (P = 0.006). MMA-positive and MMA-negative patients had similar clinical and radiographic presentations and were not significantly different for the use of ventilatory support (58% vs. 76%, P = 0.09), occurrence of shock (43% vs. 53%, P = 0.41), use of renal replacement therapy (26% vs. 23%, P = 0.92), SAPS II (35 [26–44] vs. 38 [27–50], P = 0.36), time spent in the ICU (6 vs. 7 days, P = 0.35), or ICU mortality (17% vs. 28%, P = 0.27). Using MMA, a virus was found in 6 of the 12 patients with no diagnosis at the end of the etiologic investigations.

Conclusions

In critically ill immunocompromised patients, an MMA was far more sensitive than immunofluorescence for respiratory virus detection. Patients with RVs detected in the respiratory tract had the same clinical characteristics and outcomes as other patients.

Other viral infections in solid organ transplantation

Viral infections are a major cause of morbidity and even mortality in solid organ transplant recipients. This article reviews key aspects of infections in solid organ transplant recipients from respiratory viruses, such as influenza, polyomavirus, erythrovirus B19 and measles.

Novel influenza (H1N1) infection in pediatric renal transplant recipients: a single center experience

In 2009, novel influenza A H1N1 caused significant morbidity and mortality worldwide, particularly in children. Because they are immunocompromised, pediatric transplant recipients are presumed to be at high risk. This study assessed epidemiological characteristics, presenting symptoms, and clinical course among pediatric renal transplant recipients with confirmed H1N1 infection. A retrospective review was conducted in renal transplant recipients followed at The Hospital for Sick Children (Toronto) who contracted H1N1 infection between June and November, 2009. Epidemiological, clinical, and laboratory features at presentation, and clinical course were analyzed. Of 59 children, 14 (23.7%) developed H1N1 infection. Children with H1N1 infection had undergone kidney transplantation more recently than their uninfected counterparts. The most common symptoms included fever (92.9%), cough (85.7%), headache (42.9%), and vomiting (42.9%). Fifty percent of patients required hospitalization, of median duration 3.0 (1.0-5.0) days. No child required intensive care treatment. Half the H1N1-infected children had acute renal dysfunction, with serum creatinine elevated >10% above basal values (median increase 21.6 [14.3-46.2]%). In five of the seven children, serum creatinine returned to baseline within two wk. These findings indicate that H1N1 influenza infection in pediatric kidney transplant recipients followed at our center was surprisingly mild, and produced no lasting sequelae.

Respiratory syncytial virus pneumonia treated with lower-dose palivizumab in a heart transplant recipient

Respiratory syncytial virus (RSV) is an important community-acquired pathogen that can cause significant morbidity and mortality in patients who have compromised pulmonary function, are elderly, or are immunosuppressed. This paper describes a 70-year-old man with a remote history of heart transplantation who presented with signs and symptoms of pneumonia. Chest computed tomography (CT) imaging demonstrated new patchy ground glass infiltrates throughout the upper and lower lobes of the left lung, and the RSV direct fluorescence antibody (DFA) was positive. The patient received aerosolized ribavirin, one dose of intravenous immunoglobulin, and one dose of palivizumab. After two months of followup, the patient had improved infiltrates on chest CT, improved pulmonary function testing, and no evidence of graft rejection or dysfunction. There are few data on RSV infections in heart transplant patients, but this case highlights the importance of considering this potentially serious infection and introduces a novel method of treatment.

Clinical and radiological features of respiratory syncytial virus in solid organ transplant recipients: a single-center experience

BACKGROUND

Respiratory syncytial virus (RSV) infections range from upper respiratory illness to severe lower respiratory disease. There is no universally accepted treatment for RSV in solid organ transplant (SOT) recipients.

METHODS

Retrospective review of adult SOT patients with RSV infections, between January 2007 and December 2009, in a single transplant center was performed.

RESULTS

During the 3-year period, a total of 24 adults developed RSV infection, including 12 (50%) SOT recipients (5 kidneys, 4 livers, and 3 lungs). Most cases were seen in 2009 during the influenza H1N1 pandemic, likely as a result of increased testing. In 83% of the cases, the diagnosis was based on RSV antigen detection, which was also used to follow subsequent shedding (mean duration: 20.6 days). Most of the cases presented with lower respiratory disease and required hospitalization. All the patients were on at least two classes of immunosuppressive drugs. We observed a lower lymphocyte count in patients with lower respiratory tract infection. Computed tomography was superior to chest x-ray in demonstrating pulmonary disease, with the most common findings being pulmonary nodules and ground-glass opacities. Novel radiographic findings were small cavities and pleural effusions. No co-infections were documented, and no mortality could be attributed to RSV. Inhaled or oral ribavirin was administered in 67% of the cases, with variations in the treatment regimens.

CONCLUSION

SOT recipients accounted for half of all adult cases of RSV at our institution. Type and length of treatment varied widely, and we cannot conclude that outcomes differed between treatments with oral or inhaled ribavirin. Current therapeutic management of RSV in SOT is empiric, and can be rather expensive and difficult, without clear evidence of effectiveness.

Changing epidemiology of respiratory viral infections in hematopoietic cell transplant recipients and solid organ transplant recipients

PURPOSE OF REVIEW

New respiratory viruses have been discovered in recent years and new molecular diagnostic assays have been developed that improve our understanding of respiratory virus infections. This article will review the changing epidemiology of these viruses after hematopoietic stem cell and solid organ transplantation.

RECENT FINDINGS

Respiratory viruses are frequently detected in transplant recipients. A number of viruses have been newly discovered or emerged in the last decade, including human metapneumovirus, human bocavirus, new human coronaviruses and rhinoviruses, human polyomaviruses, and a new 2009 pandemic strain of influenza A/H1N1. The potential for these viruses to cause lower respiratory tract infections after transplantation varies, and is greatest for human metapneumovirus and H1N1 influenza, but appears to be limited for the other new viruses. Acute and long-term complications in hematopoietic and solid organ transplant recipients are active areas of research.

SUMMARY

Respiratory viral infections are frequently associated with significant morbidity following transplantation and are therefore of great clinical and epidemiologic interest. As new viruses are discovered, and more sensitive diagnostic methods are developed, defining the full impact of emerging respiratory viruses in transplant recipients must be elucidated by well designed clinical studies.

Respiratory viral infections in hematopoietic stem cell and solid organ transplant recipients

Respiratory viral infections (RVIs) are common causes of mild illness in immunocompetent children and adults with rare occurrences of significant morbidity or mortality. Complications are more common in the very young, very old, and those with underlying lung diseases. However, RVIs are increasingly recognized as a cause of morbidity and mortality in recipients of hematopoietic stem cell transplants (HSCT) and solid organ transplants (SOTs). Diagnostic techniques for respiratory syncytial virus (RSV), parainfluenza, influenza, and adenovirus have been clinically available for decades, and these infections are known to cause serious disease in transplant recipients. Modern molecular technology has now made it possible to detect other RVIs including human metapneumovirus, coronavirus, and bocavirus, and the role of these viruses in causing serious disease in transplant recipients is still being worked out. This article reviews the current information regarding epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment of these infections, as well as the aspects of clinical significance of RVIs unique to HSCT or SOT.

Changing attitudes toward influenza vaccination in U.S. Kidney transplant programs over the past decade

BACKGROUND AND OBJECTIVES

Influenza infection in transplant recipients is often associated with significant morbidity. Surveys were conducted in 1999 and 2009 to find out if the influenza vaccination practices in the U.S. transplant programs had changed over the past 10 years.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 1999, a survey of the 217 United Network for Organ Sharing-certified kidney and kidney-pancreas transplant centers in the U.S. was conducted regarding their influenza vaccination practice patterns. A decade later, a second similar survey of 239 transplant programs was carried out.

RESULTS

The 2009 respondents, compared with 1999, were more likely to recommend vaccination for kidney (94.5% versus 84.4%, P = 0.02) and kidney-pancreas recipients (76.8% versus 48.5%, P < 0.001), family members of transplant recipients (52.5% versus 21.0%, P < 0.001), and medical staff caring for transplant patients (79.6% versus 40.7%, P < 0.001). Physicians and other members of the transplant team were more likely to have been vaccinated in 2009 compared with 1999 (84.2% versus 62.3% of physicians, P < 0.001 and 91.2% versus 50.3% of nonphysicians, P < 0.001).

CONCLUSIONS

Our study suggests a greater adoption of the Centers for Disease Control and Prevention influenza vaccination guidelines by U.S. transplant programs in vaccinating solid-organ transplant recipients, close family contacts, and healthcare workers.