Guidance on novel influenza A/H1N1 in solid organ transplant recipients

Deficient long-term response to pandemic vaccine results in an insufficient antibody response to seasonal influenza vaccination in solid organ transplant recipients

BACKGROUND

Little is known about the long-term antibody response to the 2009-H1N1 vaccine in solid organ transplant recipients (SOTR) and its clinical repercussion on the efficacy of following 2010-2011 influenza vaccine.

METHODS

We performed a multicenter prospective study in SOTR receiving one dose of the nonadjuvant 2010-2011 seasonal influenza vaccine and determined the immunological response at 5 weeks after vaccination.

RESULTS

One hundred SOTR were included. Long-term antibody titers to the previous vaccine were only detected in one third of the patients. Patients with baseline titers had significantly higher seroprotection for the 2009-H1N1 strain (100% vs. 73%, relative risks [RR] 1.37, 95% confidence intervals [CI] 1.19-1.57; P=0.006), for H3N2 strain (100% vs. 62.2%, RR 1.61, 95% CI 1.36-1.90; P=0.005), and for B strain (100% vs. 69%; P=0.02). The seroconversion rate in patients with baseline titers was 90.9% vs. 73% (RR 2.97, 95% CI 0.75-11.74; P=0.07) for the 2009-H1N1 strain, 92.2% vs. 62.2% (RR 5.29, 95% CI 0.8-35.7; P=0.02) for the H3N2 strain, and 58.3% vs. 69% (P=0.45) for the B strain.

CONCLUSIONS

SOTR response to the 2010-2011 influenza vaccine was not optimal. The response was related to baseline titers; however, most of the patients did not exhibit detectable antibodies at vaccination lacking long-term response. New strategies are necessary to improve vaccination efficacy.

Mycophenolate and lower graft function reduce the seroresponse of kidney transplant recipients to pandemic H1N1 vaccination

In late 2009 transplant organizations recommended that kidney recipients be vaccinated for pandemic H1N1 influenza (pH1N1); however, the vaccine efficacy was unknown. We had offered a monovalent non-adjuvanted pH1N1 vaccine to transplant recipients. Here we compared the pre- and post-vaccination seroresponses of 151 transplant recipients to that of 71 hemodialysis patients and 30 healthy controls. Baseline seroprotection was similar between groups but was significantly different at 1 month (44, 56, and 87%, respectively). Seroconversion was significantly less common for transplant recipients (32%) than dialysis patients (45%) and healthy controls (77%). After adjusting for age and gender, dialysis patients were significantly more likely (2.7-fold) to achieve new seroprotection than transplant recipients. The likelihood of seroprotection in transplant recipients was significantly reduced by mycophenolate use (adjusted odds ratio 0.24), in a dose-dependent manner, and by reduced eGFR (adjusted odds ratio 0.16 for worst to best). Seroprotection and geometric mean antibody titers increased substantially in 49 transplant recipients who subsequently received the 2010 seasonal influenza vaccine. Thus, patients requiring renal replacement therapy had reduced seroresponses to vaccination with the monovalent vaccine compared with healthy controls. Transplant recipient responses were further reduced if they were receiving mycophenolate or had significantly lower graft function.

Morbimortality of pandemic influenza A H1N1 infection in kidney transplant recipients requiring hospitalization: a comparative analysis with nonimmunocompromised patients

BACKGROUND

Clinical and epidemiological data of pandemic influenza A H1N1 infection in solid-organ transplant recipients have been described, but scarce data compare these outcomes with nonimmunocompromised patients.

METHODS

We retrospectively reviewed and compared the clinical presentation, morbidity, and mortality of all kidney transplant (KT) and nonimmunocompromised (non-KT) patients admitted for at least 12 hr with a diagnosis of pandemic influenza A H1N1 infection in a single hospital complex during the 2009 pandemic.

RESULTS

There were 22 patients in the KT group (29.3%) and 53 in the non-KT group (70.7%). The prevalence of diabetes was higher in KT group (27.3% vs. 5.7%) while chronic pulmonary disease was more frequent in non-KT group (34% vs. 9.1%). Clinical and radiological presentations and duration of disease were similar between the two groups. The incidence of acute renal failure was higher among KT patients (40.9% vs. 17%). No differences in the rate of intensive care unit admission (22.7% vs. 22.6%) or hospital mortality (9.1% vs. 7.5%) were observed. For the overall population, poor outcome, defined as intensive care unit admission or death, was associated with in-hospital acquisition (relative risk [RR]=42.6 [95% confidence interval {95% CI } 2.2-831.9], P=0.003), symptom onset more than 48 hr (RR=12.17 [95% CI 1.3-117.2], P=0.007), and acute renal failure (RR=11.8 [95% CI 2.9-48.8], P<0.001). Among KT recipients, in-hospital acquisition was the only covariate associate with poor outcome (RR=30.0 [95% CI 2.1-421.1], P=0.004).

CONCLUSIONS

No significant differences in morbidity and mortality were observed comparing KT and non-KT patients infected with pandemic H1N1 influenza A virus.

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.

An outbreak of the 2009 influenza a (H1N1) virus in a children's hospital

Please cite this paper as: Bearden et al. (2012) An outbreak of the 2009 influenza a (H1N1) virus in a children’s hospital. Influenza and Other Respiratory Viruses 6(5), 374–379.

Context  Preventing nosocomial transmission of influenza is essential to reduce the morbidity and mortality associated with this infection. In October 2009, an outbreak of the 2009 influenza A (H1N1) virus occurred in a hematology ward of a children’s hospital over a 21‐day period and involved two patients and four healthcare workers.

Objective  To investigate nosocomial transmission of the 2009 influenza A (H1N1) virus in patients and healthcare workers.

Design, setting, and participants  An outbreak investigation was initiated in response to suspected nosocomial transmission of the 2009 influenza A (H1N1) virus during the peak of the 2009 pandemic. Cases were confirmed using a polymerase chain reaction (PCR) test specific for the 2009 H1N1 influenza A virus. Viruses isolated from nasopharyngeal swabs were genetically characterized using Sanger sequencing of uncloned “bulk” PCR products.

Main outcome measures  Virus sequencing to investigate nosocomial transmission.

Results  Two immunocompromised patients and four healthcare workers were found to be part of a nosocomial outbreak of the 2009 influenza A (H1N1) virus. One immunocompromised patient had a second episode of clinical influenza infection after isolation precautions had been discontinued, resulting in additional exposures. Strain‐specific PCR showed that all cases were caused by infection of the 2009 H1N1 virus. Sequencing of viral genes encoding hemagglutinin and polymerase basic subunit 2 (PB2) revealed that all viruses isolated were genetically identical at these loci, including the two episodes occurring in the same immunocompromised patient.

Conclusions  Prompt institution of isolation precautions is essential in preventing nosocomial outbreaks of the 2009 novel influenza A (H1N1) virus. Our data suggest that isolation precautions may need to be continued for a prolonged period of time in immunocompromised patients with influenza infection.

Pandemic influenza A(H1N1) virus infection in solid organ transplant recipients: impact of viral and non-viral co-infection

Solid organ transplant recipients (SOTR) are at risk of serious influenza-related complications. The impact of respiratory co-infection in SOTR with 2009 pandemic influenza A(H1N1) is unknown. A multicentre prospective study of consecutive cases of pandemic influenza A(H1N1) in SOTR was carried out to assess the clinical characteristics and outcome and the risk factors for co-infection. Overall, 51 patients were included. Median time from transplant was 3.7 years, 5.9% of the cases occurred perioperatively and 7.8% were hospital-acquired. Pneumonia was diagnosed in 15 (29.4%) patients. Ten cases were severe (19.6%): 13.7% were admitted to intensive care units, 5.9% suffered septic shock, 5.9% developed acute graft rejection and 7.8% died. Co-infection was detected in 15 patients (29.4%): eight viral, six bacterial and one fungal. Viral co-infection did not affect the outcome. Patients with non-viral co-infection had a worse outcome: longer hospital stay (26.2 ± 20.7 vs. 5.5 ± 10.2) and higher rate of severe diseases (85.7% vs. 2.3%) and mortality (42.8% vs. 2.3%). Independent risk factors for non-viral co-infection were: diabetes mellitus and septic shock. Other factors associated with severe influenza were: delayed antiviral therapy, diabetes mellitus, time since transplantation <90 days and pneumonia. In conclusion, pandemic influenza A can cause significant direct and indirect effects in SOTR, especially in the early post-transplant period, and should be treated early. Clinicians should be aware of the possibility of non-viral co-infection, mainly in diabetic patients and severe cases. An effort should be made to prevent influenza with immunization of the patient and the environment.

Antiviral resistance during the 2009 influenza A H1N1 pandemic: public health, laboratory, and clinical perspectives

Influenza A H1N1 2009 virus caused the first pandemic in an era when neuraminidase inhibitor antiviral drugs were available in many countries. The experiences of detecting and responding to resistance during the pandemic provided important lessons for public health, laboratory testing, and clinical management. We propose recommendations for antiviral susceptibility testing, reporting results, and management of patients infected with 2009 pandemic influenza A H1N1. Sustained global monitoring for antiviral resistance among circulating influenza viruses is crucial to inform public health and clinical recommendations for antiviral use, especially since community spread of oseltamivir-resistant A H1N1 2009 virus remains a concern. Further studies are needed to better understand influenza management in specific patient groups, such as severely immunocompromised hosts, including optimisation of antiviral treatment, rapid sample testing, and timely reporting of susceptibility results.

XIth International Symposium on Respiratory Viral Infections

Please cite this paper as: Belser et al. (2011) XIth International Symposium on Respiratory Viral Infections. Influenza and Other Respiratory Viruses 5(6), 443–e457.

Antivirals and resistance: influenza virus

Influenza causes annual epidemics of respiratory viral infections are associated with significant morbidity and mortality. Influenza vaccines have been shown to reduce the risk of infection and mitigate against some of the virus' sequellae. Likewise, two classes of antivirals, the adamantanes (amantadine and rimantadine) and the neuraminidase inhibitors (laninamivir, oseltamivir, peramivir, and zanamivir) are currently approved for the prevention and treatment of influenza; several other classes of antivirals and immune modulators are also currently under investigation. One of the greatest challenges to our armamentarium of antivirals is the emergence of resistant mutants. In this paper, we will review the currently approved and investigational antiviral agents and the mechanisms of resistance that impact their activity.

Influenza vaccination in the organ transplant recipient: review and summary recommendations

Influenza virus causes a spectrum of illness in transplant recipients with a high rate of lower respiratory disease. Seasonal influenza vaccination is an important public health measure recommended for transplant recipients and their close contacts. Vaccine has been shown to be safe and generally well tolerated in both adult and pediatric transplant recipients. However, responses to vaccine are variable and are dependent on various factors including time from transplantation and specific immunosuppressive medication. Seasonal influenza vaccine has demonstrated safety and no conclusive evidence exists for a link between vaccination and allograft dysfunction. Annually updated trivalent inactivated influenza vaccines have been available and routinely used for several decades, although newer influenza vaccination formulations including high-dose vaccine, adjuvanted vaccine, quadrivalent inactivated vaccine and vaccine by intradermal delivery system are now available or will be available in the near future. Safety and immunogenicity data of these new formulations in transplant recipients requires investigation. In this document, we review the current state of knowledge on influenza vaccines in transplant recipients and make recommendations on the use of vaccine in both adult and pediatric organ transplant recipients.

Transplantation of solid organs procured from influenza A H1N1 infected donors

Following the influenza A H1N1 (swine flu) pandemic, there remains little evidence informing the safety of transplanting organs from donors suspected or diagnosed with H1N1. Limited guidelines from the major transplant societies leave the use of such organs at the discretion of individual transplant centres, and practice varies considerably both nationally and internationally. We present the largest published series of outcome following transplantation of organs from H1N1 positive donors and demonstrate that these organs can be transplanted safely and with good short-term outcome. We discuss our local policy for treatment of recipients with Oseltamivir.

Influenza A/H1N1 vaccine in patients treated by kidney transplant or dialysis: a cohort study

BACKGROUND AND OBJECTIVES

In 2009, the pandemic influenza A/H1N1 accounted for worldwide recommendations about vaccination. There are few data concerning the immunogenicity or the security of the adjuvanted-A/H1N1 vaccine in transplanted and hemodialyzed patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Sera from 21 controls, 53 hemodialyzed (HD) patients, and 111 renal transplant recipients (RT) were sampled before (T0) and 1 month after (T1) a single dose of Pandemrix® vaccine (GSK Biologicals, AS03-adjuvanted). We measured the neutralizing antibodies against A/H1N1/2009, the geometric mean (GM) titers, the GM titer ratios (T1/T0) with 95% confidence intervals, and the seroconversion rate (responders: ≥4-fold increase in titer). The HLA and MICA immunization was determined by Luminex technology.

RESULTS

The GM titer ratio was 38 (19 to 78), 9 (5 to 16), and 5 (3 to 6) for controls, HD patients, and RT patients, respectively (P < 0.001). The proportion of responders was 90%, 57%, and 44%, respectively (P < 0.001). In RT patients, the prevalence of histocompatibility leukocyte antigen (HLA) class I, histocompatibility leukocyte antigen class II, and MHC class I-related chain A immunization, was, respectively, 15%, 14%, and 14% before and 14%, 14%, and 11% after vaccination (P = 1, 1, and 0.39).

CONCLUSIONS

The influenza A/H1N1-adjuvanted vaccine is of limited efficacy but is safe in renal disease populations. The humoral response is lower in transplanted versus hemodialyzed patients. Further studies are needed to improve the efficacy of vaccination in those populations.

[H1N1 (2009) influenza A infection in transplant recipient patients: a comparative study versus non-transplanted patients]

OBJECTIVE

To compare H1N1 (2009) influenza A infection characteristics between transplant recipient patients and non-transplanted patients. To assess the evolution of transplanted patients up to 6 months following infection.

METHODS

Patients diagnosed with confirmed influenza A infection from three Parisian transplant centers between September 1st, 2009 and February 15th, 2010. Clinical symptoms, biological, and radiological findings, and management were analysed and retrospectively compared between transplanted (T) and non-transplanted patients (NT). The evolution was assessed by a follow-up questionnaire, CT results 1 to 3 months after influenza infection and FEV1 variation.

RESULTS

Seventy patients were included. Thirteen patients had an allograft (lung: eight, kidney: four, stem cells: one): (1) hospitalization: 100% (13 out of 13) in group T, 54% (31 out of 57) in group NT (P=0.0013); (2) pneumonia: 62% (eight out of 13) in group T, 26% (eight out of 57) in group NT (P=0.004); (3) mortality rate among hospitalized patients: 7.7% (one out of 13) in the group T, 9.7% (three out of 57) in group NT (P=NS); (4) chest CT scan abnormalities remained in four lung transplanted patients; (5) a minimum 10% decrease in FEV1 was detected in four lung transplant recipients.

CONCLUSION

Our results suggest that H1N1(2009) influenza A infection in transplant recipient patients compared to non-transplanted patients: (1) more often leads to hospitalization; (2) is more frequently associated with pneumonia; (3) is responsible for a persistent graft functional impairment in lung transplant recipients; (4) has a low mortality rate similar to admitted non-transplanted patients.

Efficacy of influenza A H1N1/2009 vaccine in hemodialysis and kidney transplant patients

BACKGROUND AND OBJECTIVES

Data are needed to assess safety and efficacy of the 2009 pandemic influenza A H1N1 vaccine in renal patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We prospectively evaluated seroconversion, predictors of response, and vaccine safety in renal patients. Hemagglutination inhibition tests to detect serum antibodies against a new influenza A-H1N1 virus were performed in 79 transplant patients, 48 hemodialysis patients, and 15 healthy workers before and 1 month after vaccination. Healthy controls and 88 of 127 renal patients were vaccinated. Seroconversion was defined as at least 2 dilutions increase in titer.

RESULTS

We excluded 19 individuals seroprotected (≥1/40) against the novel H1N1 in the initial sample. Efficacy rate in the 96 vaccinated individuals was 43.7% (42 of 96 seroconverted versus four of 27 nonvaccinated patients, P = 0.007). For vaccinated subgroups, efficacy was 41.8% in transplant patients (P = 0.039 versus nonvaccinated), 33.3% in hemodialysis patients (P = 0.450), and 81.8% in controls. Healthy controls showed better response to vaccine than transplant (P = 0.021) and dialysis (P = 0.012) patients. For the transplant subgroup, longer time after transplantation (P = 0.028) was associated with seroconversion, but no influence was found for age, gender, renal function, or immunosuppression. In the hemodialysis subgroup, younger age was associated with response (55.7 ± 20.8 versus 71.6 ± 10.1 years, P = 0.042), but other specific variables, including Kt/V or time on dialysis, were not. No serious adverse events were reported, and kidney function was stable.

CONCLUSION

The novel influenza A 2009 H1N1 vaccine was safe in renal patients, although administration of a single dose of adjuvanted vaccine induced a poor response in these patients.

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.

Immune response to pandemic H1N1 2009 influenza a vaccination in pediatric liver transplant recipients

After the announcement of a worldwide pandemic in June 2009, a single dose of a monovalent pandemic H1N1 2009 influenza A (pH1N1/09) vaccine was advocated for all Australians who were 10 years and older because of excellent immunogenicity trial results for healthy children and adults. Immunocompromised patients have previously been shown to have lower seroconversion rates after routine vaccinations. There is a lack of data concerning the immune response of this patient group after pH1N1/09 vaccination. The aim of this study was to assess the immunogenicity of a pH1N1/09 vaccine in pediatric liver transplant recipients 10 years of age or older. Liver transplant recipients ≥ 10 years were prospectively recruited. All participants were administered a single intramuscular injection of the pH1N1/09 vaccine (15 μg). Serum antibody levels were determined by hemagglutination immediately before and ≥ 6 weeks after vaccination. Clinical and laboratory data (age, time since transplantation, immunosuppression, and lymphocyte counts) were analyzed comparing seroconverters and nonconverters with the Student's t test. A second dose of the vaccine was offered to all those who displayed no seroprotective titers after the first vaccination. Antibody levels were again determined 6 weeks later. Twenty-one of 28 liver transplant patients completed the study. The seroconversion rate was 62% after the first dose and 89.5% after the second dose. At baseline, 7 of 21 patients (33.4%) were already seropositive. Increasing time since transplantation positively correlated with successful seroconversion. In conclusion, a single dose of a pandemic influenza A vaccine does not elicit a reliable immune response in adolescent pediatric liver transplant patients. A second dose of the vaccine is warranted in this group of patients, at least in a pandemic scenario. There is an urgent need to further assess vaccine strategies in this high-risk group.

Emerging oseltamivir resistance in seasonal and pandemic influenza A/H1N1

The emergence of oseltamivir resistance in seasonal and pandemic influenza A/H1N1 has created challenges for diagnosis and clinical management. This review discusses how clinical virology laboratories have handled diagnosis of oseltamivir-resistant H1N1 and what we have learned from clinical studies and case series. Immunocompetent patients infected with oseltamivir-resistant H1N1 have similar outcomes as patients infected with oseltamivir-susceptible H1N1. However, immunocompromised patients infected with oseltamivir-resistant H1N1 experience potentially more risks of complication and transmissibility with few therapeutic options.

Outcome of pandemic H1N1 infections in hematopoietic stem cell transplant recipients

During 2009, a new strain of A/H1N1 influenza appeared and became pandemic. A prospective study was performed to collect data regarding risk factors and outcome of A/H1N1 in hematopoietic stem cell transplant recipients. Only verified pandemic A/H1N1 influenza strains were included: 286 patients were reported, 222 allogeneic and 64 autologous recipients. The median age was 38.3 years and the median time from transplant was 19.4 months. Oseltamivir was administered to 267 patients and 15 patients received zanamivir. One hundred and twenty-five patients (43.7%) were hospitalized. Ninety-three patients (32.5%) developed lower respiratory tract disease. In multivariate analysis, risk factors were age (OR 1.025; 1.01-1.04; P=0.002) and lymphopenia (OR 2.49; 1.33-4.67; P<0.001). Thirty-three patients (11.5%) required mechanical ventilation. Eighteen patients (6.3%) died from A/H1N1 infection or its complications. Neutropenia (P=0.03) and patient age (P=0.04) were significant risk factors for death. The 2009 A/H1N1 influenza pandemic caused severe complications in stem cell transplant recipients.

Infections in liver transplant recipients

Liver transplantation is a standard life-saving procedure for the treatment of many end-stage liver diseases. The success of this procedure may be limited by infectious complications. In this article, we review the contemporary state of infectious complications during the post-operative period, with particular emphasis on those that occur most commonly during the first 6 mo after liver transplantation. Bacteria, and less commonly Candida infections, remain the predominant pathogens during the immediate post-operative period, especially during the first month, and infections caused by drug-resistant strains are emerging. Infections caused by cytomegalovirus and Aspergillus sp. present clinically during the "opportunistic" period characterized by intense immunosuppression. As newer potent immunosuppressive therapies with the major aim of reducing allograft rejection are developed, one potential adverse effect is an increase in certain infections. Hence, it is essential for liver transplant centers to have an effective approach to prevention that is based on predicted infection risk, local antimicrobial resistance patterns, and surveillance. A better understanding of the common and most important infectious complications is anticipated to lead to improvements in quality of life and survival of liver transplant recipients.

Increased mortality of solid organ transplant recipients with H1N1 infection: a single center experience

Immunosuppressed solid organ transplant recipients are included in the cohort at increased risk for complications of viral infections such as the newly encountered H1N1. A retrospective review was performed to collect data on patients hospitalized during a recent H1N1 epidemic. H1N1 was suspected based on symptoms and real-time reverse-transcriptase-polymerase-chain-reaction assay confirmed the diagnosis. From August through October of 2009, 89 patients were admitted to The Methodist Hospital, Houston, Texas, with H1N1. Eighteen were solid organ transplant recipients with an age range of 34-69 yr. This group included nine kidney, five lung, one kidney-pancreas, one liver, and two heart recipients. Severe cardiac or pulmonary comorbidities existed in over half of non-transplant patients, while only eight of these non-transplant patients were otherwise healthy. Eighty-nine percent of transplant patients presented with fever or chills, 72% with cough, and 56% with gastrointestinal distress. Symptoms were similar to non-transplant patients. All transplant patients were treated with oseltamivir. Two non-transplant patients and three transplant patients died. Thirty-day survival was 97% in non-transplant and 83% in transplant patients (p=0.02). In the context of an initial epidemic of H1N1, infection was associated with increased risk of complications and mortality in solid organ transplant recipients.

Differences in clinical outcomes after 2009 influenza A/H1N1 and seasonal influenza among hematopoietic cell transplant recipients

It is not known whether pandemic 2009 influenza A/H1N1 (2009 H1N1) leads to more serious disease than seasonal influenza in hematopoietic cell transplant (HCT) recipients. In a retrospective study in HCT recipients with virologically proven influenza virus infection, a total of 161 HCT recipients (18 2009 H1N1, 103 seasonal influenza A, and 40 seasonal influenza B) were analyzed. In multivariable analyses, more patients with 2009 H1N1 had lower respiratory tract disease (LRD), hypoxemia, and prolonged viral shedding compared with seasonal influenza A. Seasonal influenza A and B outcomes were similar. There was no difference in overall and influenza-associated mortality among influenza virus types. Both early and delayed administration of antiviral therapy was shown to be beneficial in terms of decreased rates of development of LRD, although earlier intervention appeared to be more effective. Profound lymphopenia and lack of early antiviral therapy were associated significantly with LRD, hypoxemia, and death. High-dose corticosteroid treatment (≥ 1 mg/kg) given at the time of influenza diagnosis was associated with a reduced risk for mechanical ventilation. Thus, our data suggest that infection with 2009 influenza A/H1N1 resulted in more severe respiratory disease in HCT recipients compared with seasonal influenza.

The impact of pandemic influenza A H1N1 2009 on Australian lung transplant recipients

Influenza A H1N1 2009 led to 189 deaths during the Australian pandemic. Community-acquired respiratory viruses not only can cause prolonged allograft dysfunction in lung transplant recipients but have also been linked to bronchiolitis obliterans syndrome (BOS). We report the impact of the 2009 H1N1 pandemic on Australian lung transplant recipients. An observational study of confirmed H1N1 cases was conducted across five Australian lung transplant programs during the pandemic. An electronic database collected patient demographics, clinical presentation, management and outcomes up to a year follow-up. Twenty-four H1N1 cases (mean age 43 ± 14 years, eight females) were identified, incidence of 3%. Illness severity varied from upper respiratory tract symptoms only in 29% to lung allograft dysfunction (≥10% decline FEV1) in 75% to death in 5 (21%) cases (pre-existing BOS grade 3, n = 4). Treatment with oseltamivir occurred in all but one case confirmed after death, reduced immunosuppression, n = 1, augmented corticosteroid therapy, n = 16, and mechanical/noninvasive ventilation, n = 4. There was BOS grade decline within a year in six cases (32%). In conclusion, Australian lung transplant recipients were variably affected by the H1N1 pandemic mirroring the broader community with significant morbidity and mortality. After initial recovery, a considerable proportion of survivors have demonstrated BOS progression.

Early post-transplant vaccination with pandemic influenza A/H1N1 vaccine in pediatric heart transplant recipients

Pandemic influenza A/H1N1 virus has the potential to cause severe disease in pediatric transplant patients. A pandemic vaccine against H1N1 is effective in immunocompetent children. We investigated the immunogenicity of this vaccine when given in the first six months after heart transplantation. Four patients younger than two yr received two doses of vaccine and one patient older than seven yr received one dose. Titers were obtained using the HAI at baseline and after final immunization. Five patients were enrolled, ages 0.5-7 yr. Median age at the time of transplant was five months (range 3 wk-7 yr). All patients received induction with anti-thymoglobulin and maintenance immunosuppression with tacrolimus, MMF, and prednisone. Patients were immunized with the adjuvanted H1N1 vaccine after heart transplant at median time of nine wk (range 5-23 wk) post-transplant. Three of five developed protective titers against H1N1. A proportion of pediatric patients may respond to influenza vaccine even when immunized in the early post-transplant period.

Pandemic influenza A/H1N1 virus infection in solid organ transplant recipients: a multicenter study

BACKGROUND

The 2009 novel influenza A/H1N1 virus pandemic did not spare solid organ transplant (SOT) recipients. We aimed to describe the behavior of pandemic influenza infection in a group of SOT recipients in Argentina.

METHODS

Data from 10 transplant (Tx) centers were retrospectively collected for SOT that presented with a respiratory illness compatible with pandemic influenza A infection, between May and September 2009. Cases were defined as suspected, probable, or confirmed according to diagnostic method.

RESULTS

Seventy-seven cases were included. No significant differences in presenting symptoms, pulmonary infiltrates, and graft involvement were found among 35 suspected, 19 probable, and 23 confirmed cases. The 33 ambulatory cases had significantly more sore throat and headache when compared with 34 cases admitted to medical ward (MW) and 10 admitted to intensive care unit (ICU), 9 of whom required ventilatory support. MW and ICU cases had significantly more dyspnea, hypoxemia, pulmonary infiltrates, and graft dysfunction. Time from onset of symptoms to first visit and to treatment was significantly longer in MW and ICU cases (P=0.008). Coinfections were found in six cases. Most cases received oseltamivir for 5 to 10 days. Six patients (7.8%) died from viral infection at a median of 15 days from admission. No differences in outcome were seen related to the transplanted organ, the immunosuppressive regimen, time from Tx, or confirmation of diagnosis.

CONCLUSIONS

Mortality is higher in Tx recipients than in the general population. Poor outcome seems to be related to a delay in the beginning of treatment.

Oseltamivir-resistant influenza A 2009 H1N1 virus in immunocompromised patients

BACKGROUND

First-line treatment of influenza A 2009 H1N1 relies on neuraminidase inhibitors such as oseltamivir. Resistance conferred by the H275Y neuraminidase gene mutation is concerning and likely to increase.

OBJECTIVES

To characterize oseltamivir resistance in a hospital-based patient population.

PATIENTS AND METHODS

All available respiratory specimens positive for influenza A by direct fluorescent antibody, RT-PCR, or culture from patients at the University of Utah 5/09-12/09 were collected. Specimens were confirmed as 2009 H1N1 by the Utah Department of Health. RT-PCR and pyrosequencing were used to test for the H275Y mutation (CDC protocol). PyroMark Q24 AQ software (Qiagen, Valencia, CA, USA) was used to allow for quantitative H275Y mutation analysis. Medical records of patients with resistant virus were reviewed.

RESULTS

We tested 191 influenza A virus-positive samples from 187 unique patients. Fifty (27%) patients were hospitalized. Four patient specimens (2.1%) were found to carry the H275Y mutation. Three patients were hospitalized, representing 6% of inpatient samples tested. Three patients had undergone hematopoietic stem cell transplant in the past year. Two patients died. Their influenza viruses were confirmed to be oseltamivir-resistant at an independent reference laboratory and through the Center for Disease Control and Prevention (CDC). One patient reported no history of prior oseltamivir exposure.

CONCLUSIONS

Widespread oseltamivir resistance among 2009 H1N1 remains a potential threat. Rapid techniques, such as pyrosequencing, which has the additional benefit of identifying mixed mutant populations of virus, may play a key role in identifying at-risk individuals and potentially unsuspected cases. Targeted surveillance of immunocompromised patients will be critical toward improving future influenza planning and therapy.

Novel Influenza A (H1N1/09) Virus Infection during Pregnancy in a Kidney Transplant Recipient

We report the first case of a pregnant renal transplant patient with H1N1/09 infection. The woman showed a mild clinical course after diagnosis of H1N1/09 infection and therapy with oseltamivir (2 × 45 mg per day). After delivery by cesarean section, the neonate exhibited moderate respiratory and circulatory dysregulation, which spontaneously normalised a few days postpartum. In conclusion, rapid diagnosis of H1N1/09 and dose-adapted therapy with oseltamivir resulted in successful delivery of a healthy infant in our renal transplanted patient but emphasized the need for consequent vaccination strategies in pregnant transplant recipients for new influenza A pandemics in the future.

Challenges in the diagnosis of 2009 H1N1 in a lung transplant patient and the long-term implications for prevention and treatment: a case report

Although respiratory viral infections have been associated with acute rejection and bronchiolitis obliterans syndrome, the long-term impact of the novel pandemic influenza A (2009 H1N1) virus on lung transplant patients has not been defined. We describe the diagnostic challenges and long-term consequences of 2009 H1N1 infection in a lung transplant patient, discuss the potential implications for prevention and treatment, and conclude that even timely antiviral therapy may be insufficient to prevent long-term morbidity.

Pandemic (H1N1) 2009 infection in adult solid organ transplant recipients in Singapore

BACKGROUND

Influenza can produce significant complications in immunocompromised persons.

METHODS

We studied the effects of the pandemic (H1N1) 2009 (pH1N1) infection on solid organ transplant recipients in our hospital, with emphasis on clinical information, duration of viral culture positivity, polymerase chain reaction positivity, effects of oseltamivir therapy, and graft status at 6 months of follow-up.

RESULTS

Twenty-two cases of pH1N1 infection involving 18 renal, two lung, one heart, and one liver transplant recipients were seen from July 14 to September 8, 2009. Their median age was 50.5 years (range 20-70 years); 64% were women, and median time posttransplant was 40 months (range 6-204 months). Common symptoms were fever (86%), cough (77%), sore throat (55%), phlegm (32%), and myalgia (27%). The median duration of symptoms (n=21) and duration of polymerase chain reaction positivity (n=15) were 7 (range 4-13 days) and 8 days (range 4-16 days), respectively. Mean (± SD) duration of symptom resolution (7.4 ± 3.0 vs. 7.8 ± 3.0 days, P=0.76) and viral culture positivity (5.3 ± 2.8 vs. 4.3 ± 3.2 days, P=0.65) did not differ between those who received a 5-day (n=9) or 10-day (n=12) course of oseltamivir. Five patients (22.7%) developed pneumonia with three needing intensive care. Mortality rate was 4.5% (1/22). At 6 months, three graft rejections involving two renal and one lung developed.

CONCLUSIONS

Our findings indicate that the pH1N1 infection in solid organ transplant recipients is associated with some degree of morbidity and may affect the function of the transplanted organ. In this nonrandomized comparison, patients treated with 5 days of oseltamivir did not fare worse compared with those who received 10 days.

2009 H1N1 influenza in hospitalized transplant recipients

BACKGROUND

The 2009 H1N1 influenza virus was first identified in April 2009 and rapidly evolved into a pandemic. There are limited reports of 2009 H1N1 influenza in transplant recipients. We report on our experience with hospitalized transplant recipients with 2009 H1N1 influenza virus.

METHODS

Ongoing review of hospitalized 2009 H1N1 influenza cases identified six patients who had received transplants. Clinical characteristics and outcomes were abstracted from the medical record.

RESULTS

Between April 27 and November 30, 2009, 29 patients with influenza A virus were admitted to the Mayo Clinic Hospital. Six of the 29 patients were transplant recipients; 4 were confirmed to have 2009 H1N1 influenza virus. Most patients presented with an acute febrile respiratory illness. Duration of antiviral treatment was 5 to 7 days except for one patient who was treated for 11 days until withdrawal of care. Prolonged viral shedding was not noted, and the patients recovered promptly except for a patient with recalcitrant multiple myeloma who died because of the disease.

CONCLUSION

2009 H1N1 influenza disease in this cohort of hospitalized transplant recipients was relatively mild. The majority of the patients improved promptly, and prolonged viral shedding was not noted.

An open-label, randomized clinical trial assessing immunogenicity, safety and tolerability of pandemic influenza A/H1N1 MF59-adjuvanted vaccine administered sequentially or simultaneously with seasonal virosomal-adjuvanted influenza vaccine to paediatric kidney transplant recipients

Background. The aim of this study was to investigate the immunogenicity, safety and tolerability of the 2009 A/H1N1 MF59-adjuvanted influenza vaccine, administered sequentially or simultaneously with the seasonal 2009–10 virosomal-adjuvanted influenza vaccine, to paediatric kidney transplant recipients.

Methods. Thirty-two children and adolescents with transplanted kidneys and 32 age- and gender-matched healthy controls were randomized 1:1 to receive the pandemic vaccine upon enrolment and the seasonal vaccine 1 month later (16 transplant recipients and 16 healthy controls), or to receive the two vaccines simultaneously upon enrolment (16 transplant recipients and 16 healthy controls).

Results. When the pandemic vaccine was administered sequentially to the seasonal vaccine, it was significantly less immunogenic in the patients than in the controls (P < 0.05); when it was administered together with the seasonal vaccine, the immune response of both patients (P < 0.05) and controls (P < 0.05) was significantly greater than when it was administered sequentially. Seroconversion rates and the geometric mean titres of all of the seasonal antigens were significantly lower in the patients, regardless of the type of vaccine administration (P < 0.05). Simultaneous administration was associated with a better immune response against A/H1N1 and A/H3N2 antigens in both patients and controls, and did not increase the mild local and systemic reactions. No impact on renal function was observed.

Conclusions. Paediatric kidney transplant recipients have a lower immune response to the pandemic influenza A/H1N1 MF59-adjuvanted and seasonal virosomal-adjuvanted influenza vaccines than healthy controls. The simultaneous administration of the two vaccines seems to increase immune response to both pandemic and seasonal A/H1N1 and A/H3N2 antigens, and has the same safety profile as that of the pandemic vaccine administered sequentially to the seasonal vaccine.

Influenza, including the novel H1N1, in organ transplant patients

PURPOSE OF REVIEW

This article will review the epidemiology, diagnosis, prevention and management of influenza in solid organ transplant recipients.

RECENT FINDINGS

A number of recent studies have documented that influenza vaccination is both well tolerated and generally effective in producing an immunologic response in most solid organ transplant (SOT) recipients. Antiviral use is associated with improved clinical outcomes, but prolonged shedding may require a longer course of therapy than what is currently approved by the FDA. Antiviral resistance emerges rarely in transplant patients and should be considered in all patients with an inadequate clinical and/or virologic response.

SUMMARY

Influenza is associated with significant morbidity and mortality, particularly in lung transplant recipients. Molecular diagnostics are preferred over other diagnostic modalities, if available. Influenza vaccination is well tolerated and provides protective benefit in most SOT recipients; in those with contraindications to vaccination or in whom responses are predicted to be poor, antivirals may be considered. Antiviral therapy is associated with improved outcomes in transplant patients and treatment should be continued until clinically and virologic response have been documented. Resistance, particularly with patients infected with the pandemic influenza A/H1N1, should be considered and treated with an antiviral with predicted activity.

New influenza A (H1N1/09) in three renal transplant patients

The pandemic new influenza A (H1N1/09) virus may be especially threatening for immunosuppressed renal transplant patients as they are at increased risk for complications, prolonged infection and mortality. This is the first case report of renal transplant patients with PCR-confirmed H1N1 respiratory tract infection. They showed a surprisingly mild clinical course despite respiratory fungal or viral co-infections in two cases. Treatment with oseltamivir in standard dosage was immediately started after diagnosis and proved to be rapidly beneficial with respect to clinical outcome and virus shedding without deteriorating renal transplant function.

Outcomes from pandemic influenza A H1N1 infection in recipients of solid-organ transplants: a multicentre cohort study

BACKGROUND

There are few data on the epidemiology and outcomes of influenza infection in recipients of solid-organ transplants. We aimed to establish the outcomes of pandemic influenza A H1N1 and factors leading to severe disease in a cohort of patients who had received transplants.

METHODS

We did a multicentre cohort study of adults and children who had received organ transplants with microbiological confirmation of influenza A infection from April to December, 2009. Centres were identified through the American Society of Transplantation Influenza Collaborative Study Group. Demographics, clinical presentation, treatment, and outcomes were assessed. Severity of disease was measured by admission to hospital and intensive care units (ICUs). The data were analysed with descriptive statistics. Proportions were compared by use of chi(2) tests. We used univariate analysis to identify factors leading to pneumonia, admission to hospital, and admission to an ICU. Multivariate analysis was done by use of a stepwise logistic regression model. We analysed deaths with Kaplan-Meier survival analysis.

FINDINGS

We assessed 237 cases of medically attended influenza A H1N1 reported from 26 transplant centres during the study period. Transplant types included kidney, liver, heart, lung, and others. Both adults (154 patients; median age 47 years) and children (83; 9 years) were assessed. Median time from transplant was 3.6 years. 167 (71%) of 237 patients were admitted to hospital. Data on complications were available for 230 patients; 73 (32%) had pneumonia, 37 (16%) were admitted to ICUs, and ten (4%) died. Antiviral treatment was used in 223 (94%) patients (primarily oseltamivir monotherapy). Seven (8%) patients given antiviral drugs within 48 h of symptom onset were admitted to an ICU compared with 28 (22.4%) given antivirals later (p=0.007). Children who received transplants were less likely to present with pneumonia than adults, but rates of admission to hospital and ICU were similar.

INTERPRETATION

Influenza A H1N1 caused substantial morbidity in recipients of solid-organ transplants during the 2009-10 pandemic. Starting antiviral therapy early is associated with clinical benefit as measured by need for ICU admission and mechanical ventilation.

FUNDING

None.