Severe novel influenza A (H1N1) infection in cancer patients

Revolutionizing oncology care: pioneering AI models to foresee pneumonia-related mortality

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality among patients with cancer, and survival time is a primary concern. Despite their importance, there is a dearth of accurate predictive models in clinical settings. This study aimed to determine the incidence of pneumonia as a cause of death in patients with cancer, analyze trends and risk factors associated with mortality, and develop corresponding predictive models.

METHODS

We included 26,938 cancer patients in the United States who died from pneumonia between 1973 and 2020, as identified through the Surveillance, Epidemiology, and End Results (SEER) program. Cox regression analysis was used to ascertain the prognostic factors for patients with cancer. The CatBoost model was constructed to predict survival rates via a cross-validation method. Additionally, our model was validated using a cohort of cancer patients from our institution and deployed via a free-access software interface.

RESULTS

The most common cancers resulting in pneumonia-related deaths were prostate (n=7300) and breast (n=5107) cancers, followed by lung and bronchus (n=2839) cancers. The top four cancer systems were digestive (n=5882), endocrine (n=5242), urologic (n=5198), and hematologic (n=3104) systems. The majority of patients were over 70 years old (57.7%), and 54.4% were male. Our CatBoost model demonstrated high precision and accuracy, outperforming other models in predicting the survival of cancer patients with pneumonia (6-month AUC=0.8384,1-year AUC=0.8255,2-year AUC=0.8039, and 3-year AUC=0.7939). The models also revealed robust performance in an external independent dataset (6-month AUC=0.689; 1-year AUC=0.838; 2-year AUC=0.834; and 3-year AUC=0.828). According to the SHAP explanation analysis, the top five factors affecting prognosis were surgery, stage, age, site, and sex; surgery was the most significant factor in both the short-term (6 months and 1 year) and long-term (2 years and 3 years) prognostic models; surgery improved patient prognosis for digestive and endocrine tumor sites with respect to both short- and long-term outcomes but decreased the prognosis of urological and hematologic tumors.

CONCLUSION

Pneumonia remains a major cause of illness and death in patients with cancer, particularly those with digestive system cancers. The early identification of risk factors and timely intervention may help mitigate the negative impact on patients' quality of life and prognosis, improve outcomes, and prevent early deaths caused by infections, which are often preventable.

The Effects of Different Respiratory Viruses on the Oxidative Stress Marker Levels in an In Vitro Model: A Pilot Study

Respiratory viruses are among the most common causes of human infections. Examining pathological processes linked to respiratory viral infections is essential for diagnosis, treatment strategies, and developing novel therapeutics. Alterations in oxidative stress levels and homeostasis are significant processes associated with respiratory viral infections. The study aimed to compare selected oxidative stress markers: total oxidative status (TOS), total antioxidant capacity (TAC), and the oxidative stress index (OSI) levels and glutathione peroxidase (GPx) and glutathione reductase (GR) activities in normal (MRC5 cell line) and tumor (A549 cell line) lung cells infected with human coronaviruses (HCoV) OC43 and 229E, human adenovirus type 5 (HAdV5), or human rhinovirus A (HRV A). We observed that a respiratory viral infection more significantly affected non-enzymatic oxidative stress markers in a lung adenocarcinoma model (A549 cells), while human lung fibroblasts (MRC-5 cell line) presented changes in enzymatic and non-enzymatic oxidative stress markers. We suggest that further detailed research is required to analyze this phenomenon.

Generation of Human Lung Organoid Cultures from Healthy and Tumor Tissue to Study Infectious Diseases

Three-dimensional (3D) human lung organoids reflect the native cell composition of the lung as well as its physiological properties. Human 3D lung organoids offer ideal conditions, such as timely availability in large quantities and high physiological relevance for reassessment and prediction of disease outbreaks of respiratory pathogens and pathogens that use the lung as a primary entry portal.

Lung Histopathology in Coronavirus Disease 2019 as Compared With Severe Acute Respiratory Sydrome and H1N1 Influenza: A Systematic Review

BACKGROUND

Patients with severe coronavirus disease 2019 (COVID-19) have respiratory failure with hypoxemia and acute bilateral pulmonary infiltrates, consistent with ARDS. Respiratory failure in COVID-19 might represent a novel pathologic entity.

RESEARCH QUESTION

How does the lung histopathology described in COVID-19 compare with the lung histopathology described in SARS and H1N1 influenza?

STUDY DESIGN AND METHODS

We conducted a systematic review to characterize the lung histopathologic features of COVID-19 and compare them against findings of other recent viral pandemics, H1N1 influenza and SARS. We systematically searched MEDLINE and PubMed for studies published up to June 24, 2020, using search terms for COVID-19, H1N1 influenza, and SARS with keywords for pathology, biopsy, and autopsy. Using PRISMA-Individual Participant Data guidelines, our systematic review analysis included 26 articles representing 171 COVID-19 patients; 20 articles representing 287 H1N1 patients; and eight articles representing 64 SARS patients.

RESULTS

In COVID-19, acute-phase diffuse alveolar damage (DAD) was reported in 88% of patients, which was similar to the proportion of cases with DAD in both H1N1 (90%) and SARS (98%). Pulmonary microthrombi were reported in 57% of COVID-19 and 58% of SARS patients, as compared with 24% of H1N1 influenza patients.

INTERPRETATION

DAD, the histologic correlate of ARDS, is the predominant histopathologic pattern identified in lung pathology from patients with COVID-19, H1N1 influenza, and SARS. Microthrombi were reported more frequently in both patients with COVID-19 and SARS as compared with H1N1 influenza. Future work is needed to validate this histopathologic finding and, if confirmed, elucidate the mechanistic underpinnings and characterize any associations with clinically important outcomes.

Prevalence and healthcare utilization of acute respiratory infections among cancer survivors in the United States: a population-based study

Objective: To examine the prevalence and healthcare use of acute respiratory tract infections (RTIs) among cancer survivors in the United States in a population-based cohort.Methods: Medical Expenditure Panel Survey for 2013, 2015, and 2017 was accessed and adults (>20 years) with known status of cancer diagnosis were reviewed. Multivariable logistic regression analysis was then used to examine factors associated with the likelihood of influenza and pneumonia as well as the likelihood of hospitalization secondary to acute RTIs.Results: A total of 75,665 participants were included (including 6397 cancer survivors and 68,733 participants without a cancer history). Within the cohort of cancer survivors, upper RTIs were recorded in 10.6% and influenza and pneumonia were recorded in 7.8%. Within the cohort of cancer survivors, individuals with influenza and pneumonia have a higher total healthcare expenditure (mean: 19,387.59 $ versus 12,714.57 $; P < 0.001) and total out-of-pocket expenditure (mean: 1494.61 $ versus 1159.27 $; P < 0.001). Multivariable logistic regression analysis showed that a history of cancer was associated with a higher likelihood of influenza and pneumonia (OR: 1.119; 95% CI: 1.005-1.247; P = 0.041) as well as hospitalization following acute RTIs (1.586; 95% CI: 1.197-2.103; P = 0.001).Conclusions: Within the studied cohort, cancer Survivors were more likely to be diagnosed with influenza and pneumonia and they were more likely to be hospitalized because of acute RTIs.

Influenza and pneumonia-attributed deaths among cancer patients in the United States; a population-based study

Objective: To assess the patterns and trends of influenza and pneumonia-attributed deaths among cancer patients in the United States.Methods: Surveillance, Epidemiology and End Results (SEER) database was accessed and cancer patients diagnosed 1975-2016 who have been included in the SEER-9 registries were included. The primary endpoint of the study is standardized mortality rate (SMR; calculated as observed/ Expected (O/E) ratio for death from influenza and pneumonia among cancer patients).Results: The current study evaluates a total of 3,579,199 cancer patients (diagnosed 1975-2016) within the SEER-9 registries; and influenza and pneumonia-attributed deaths represent 1.5% of the recorded deaths for this cohort. SMR for influenza/ pneumonia-attributed death within the first year following cancer diagnosis was 1.88 (1.83-1.94);while SMR for influenza/pneumonia-attributed death following the first year was 1.11 (1.10-1.12). Within the first year following cancer diagnosis, SMR from influenza/pneumonia was higher among individuals with black race (SMR for white race: 1.75 (95% CI: 1.69-1.81) while SMR for black race: 2.90 (95% CI: 2.65-3.16), lung cancer (SMR for lung cancer: 4.39 (95% CI: 4.11-4.69)), head and neck cancer (SMR for oral cavity/ pharynx cancer: 4.02 (95% CI: 3.50-4.59)), lymphomas (SMR for lymphoma: 3.28 (95% CI: 2.92-3.68)), leukemias (SMR for leukemia: 3.32 (95% CI: 2.89-3.80)) and myeloma (SMR for myeloma: 3.91 (95% CI: 3.28-4.63)).Conclusions: Cancer patients are more likely to have influenza/ pneumonia-attributed death compared to the general US population. This risk is higher among patients with lung cancer, head and neck cancer, and hematological malignancies.

Outcome of Patients Admitted to Intensive Care Units due to Influenza-Related Severe Acute Respiratory Illness in 2017-2018 Flu Season: A Multicenter Study from Turkey

BACKGROUND

Influenza can cause severe acute respiratory illness (SARI), which occurs as local outbreaks or seasonal epidemics with high intensive care unit (ICU) admission and mortality rates. Mortality is mainly due to SARI.

OBJECTIVE

The aim of this study was to evaluate the outcome of patients admitted to ICU due to influenza-related SARI in 2017-2018 flu season in Turkey.

METHODS

A retrospective multicenter study was conducted in 13 ICUs with a total of 216 beds from 6 cities in Turkey. All adult patients (over 18 years) admitted to the ICUs in 2017-2018 flu season (between September 1, 2017, and April 30, 2018) because of SARI and with a positive nasopharyngeal swab for influenza were included in the study.

RESULTS

A total of 123 cases were included in the study. The mean age of patients was 64.5 ± 17.5 years, and 66 (53.7%) patients were older than 65 years. The ICU mortality was 33.9%, and hospital mortality was 35.6%. Invasive mechanical ventilation (IMV), acute kidney injury (AKI), hematologic malignancy, and >65 years of age were the factors affecting mortality in influenza.

CONCLUSION

SARI due to influenza carries a high mortality rate, and IMV, AKI, presence of hematologic malignancy, and older age are independent risk factors for mortality.

Influenza vaccination of cancer patients during PD-1 blockade induces serological protection but may raise the risk for immune-related adverse events

Background

Immune checkpoint inhibiting antibodies were introduced into routine clinical practice for cancer patients. Checkpoint blockade has led to durable remissions in some patients, but may also induce immune-related adverse events (irAEs). Lung cancer patients show an increased risk for complications, when infected with influenza viruses. Therefore, vaccination is recommended. However, the efficacy and safety of influenza vaccination during checkpoint blockade and its influence on irAEs is unclear. Similarly, the influence of vaccinations on T cell-mediated immune reactions in patients during PD-1 blockade remains poorly defined.

Methods

We vaccinated 23 lung cancer patients and 11 age-matched healthy controls using a trivalent inactivated influenza vaccine to investigate vaccine-induced immunity and safety during checkpoint blockade.

Results

We did not observe significant differences between patients and healthy controls in vaccine-induced antibody titers against all three viral antigens. Influenza vaccination resulted in protective titers in more than 60% of patients/participants. In cancer patients, the post-vaccine frequency of irAEs was 52.2% with a median time to occurrence of 3.2 months after vaccination. Six of 23 patients (26.1%) showed severe grade 3/4 irAEs. This frequency of irAEs might be higher than the rate previously published in the literature and the rate observed in a non-study population at our institution (all grades 25.5%, grade 3/4 9.8%).

Conclusions

Although this is a non-randomized trial with a limited number of patients, the increased rate of immunological toxicity is concerning. This finding should be studied in a larger patient population.

Managing the oncologic patient with suspected pneumonia in the intensive care unit

INTRODUCTION

Solid cancer patients are frequently admitted in intensive care units for critical events. Improving survival rates in this setting is considered an achievable goal today. Respiratory failure is the main reason for admission, representing a primary target for research.

AREAS COVERED

This review presents a diagnostic and therapeutic algorithm for pneumonia and other severe respiratory events in the solid cancer population. It aims to increase awareness of the risk factors and the different etiologies in this changing scenario in which neutropenia no longer seems to be a decisive factor in poor outcome. Bacterial pneumonia is the leading cause, but opportunistic diseases and non-infectious etiologies, especially unexpected adverse effects of radiation, biological drugs and monoclonal antibodies, are becoming increasingly frequent. Options for respiratory support and diagnostics are discussed and indications for antibiotics in the management of pneumonia are detailed. Expert commentary: Prompt initiation of critical care to facilitate optimal decision-making in the management of respiratory failure, early etiological assessment and appropriate antibiotic therapy are cornerstones in management of severe pneumonia in oncologic patients.

Noninvasive mechanical ventilation in high-risk pulmonary infections: a clinical review

The aim of this article was to review the role of noninvasive ventilation (NIV) in acute pulmonary infectious diseases, such as severe acute respiratory syndrome (SARS), H1N1 and tuberculosis, and to assess the risk of disease transmission with the use of NIV from patients to healthcare workers. We performed a clinical review by searching Medline and EMBASE. These databases were searched for articles on "clinical trials" and "randomised controlled trials". The keywords selected were non-invasive ventilation pulmonary infections, influenza-A (H1N1), SARS and tuberculosis. These terms were cross-referenced with the following keywords: health care workers, airborne infections, complications, intensive care unit and pandemic. The members of the International NIV Network examined the major results regarding NIV applications and SARS, H1N1 and tuberculosis. Cross-referencing mechanical ventilation with SARS yielded 76 studies, of which 10 studies involved the use of NIV and five were ultimately selected for inclusion in this review. Cross-referencing with H1N1 yielded 275 studies, of which 27 involved NIV. Of these, 22 were selected for review. Cross-referencing with tuberculosis yielded 285 studies, of which 15 involved NIV and from these seven were selected. In total 34 studies were selected for this review. NIV, when applied early in selected patients with SARS, H1N1 and acute pulmonary tuberculosis infections, can reverse respiratory failure. There are only a few reports of infectious disease transmission among healthcare workers.

Antiviral prophylaxis in patients with solid tumours and haematological malignancies--update of the Guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO)

Reactivation of viral infections is common in patients with solid tumour or haematological malignancy. Incidence and severity depend on the extent of cellular immunosuppression. Antiviral prophylaxis may be effective to prevent viral reactivation. In 2006, the Infectious Diseases Working Party of German Society for Hematology and Medical Oncology (DGHO) published guidelines for antiviral prophylaxis in these patient populations. Here, we present an update of these guidelines for patients with solid and haematological malignancies undergoing antineoplastic treatment but not allogeneic stem cell transplantation. Relevant literature for reactivation of different viruses (herpes simplex virus (HSV), varicella zoster virus (VZV), hepatitis B virus (HBV) and respiratory viruses) is discussed to provide evidence-based recommendations for clinicians taking care of this patient population. We recommend a risk-adapted approach with (val)acyclovir against HSV and VZV in patients treated with alemtuzumab, bortezomib or purine analogues. Seasonal vaccination against influenza is recommended for all patients with solid or haematological malignancies regardless of antineoplastic therapy. Hepatitis B screening is recommended in lymphoproliferative disorders, acute leukaemia, and breast cancer, and during treatment with monoclonal anti-B-cell antibodies, anthracyclines, steroids and in autologous stem cell transplantation. In those with a history of hepatitis B prophylactic lamivudine, entecavir or nucleotide analogues as adefovir are recommended to prevent reactivation.

Immunogenicity of a 2009 pandemic influenza virus A H1N1 vaccine, administered simultaneously with the seasonal influenza vaccine, in children receiving chemotherapy

BACKGROUND

No examination of simultaneous vaccination against pandemic H1N1 and the seasonal influenza virus strains, in children with cancer receiving chemotherapy, are yet published. We investigated the immunogenicity of a whole-virion, inactivated, adjuvanted pandemic H1N1, and seasonal influenza vaccines administered simultaneously to children with cancer undergoing chemotherapy.

PROCEDURE

We prospectively enrolled 27 pediatric patients receiving therapy for various types of cancer. All received influenza vaccination once in a seasonal risk period. We checked hemaglutination-inhibition (HAI) antibody titers in the sera of patients before, and 21-28 days after vaccination. Seroprotective titer was defined as an antibody titer ≥ 40, and seroresponse as ≥ 4-fold increase in antibody titers after vaccination.

RESULTS

The pre- and post-vaccination seroprotective rates were H1N1: 33-48%, H3N2: 56-78%, B: 0-15% for seasonal influenza, and for pandemic H1N1: 15-37%. The seroresponse rates for seasonal influenza H1N1, H3N2, and B were 22%, 37%, and 22%, respectively, and 30% for the pandemic H1N1 vaccine.

CONCLUSIONS

Whole-virion, inactivated, adjuvanted vaccine for the pandemic H1N1 Influenza A virus and the seasonal influenza vaccines were found safe and partially immunogenic in children with cancer receiving chemotherapy. The only determinants of responsiveness were lymphocyte count and serum immunoglobulin-G. Only influenza B vaccine elicited significant differences in differences in pre- and post-vaccination seroprotective rates. The response to vaccination for pandemic H1N1 is as effective as other vaccines, however administration of a single vaccine during chemotherapy is more comfortable for pediatric cancer patients.

Ventilatory Strategy Used for Management of Acute Respiratory Failure Due to Novel Influenza A(H1N1) Infection

The first cases of the novel influenza A(H1N1) virus were reported in April 2009, especially in Mexico and the United States [1, 2]. The disease spread rapidly, becoming a pandemic by June 2009. On August 21, 2009, a total of 177 reported cases of novel influenza 182.166 A(H1N1) infection, of which 1,799 were fatal [2]. It has been observed in animal studies that the novel influenza virus A has a high replication rate in lung tissue, with a great capacity to invade the lower respiratory tract in humans, causing especially acute fulminant respiratory failure.

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.

How Does Influenza A (H1N1) Infection Proceed in Allogeneic Stem Cell Transplantation Recipients?

The clinical course of influenza A (H1N1) infection in allogeneic hematopoietic stem cell transplantation (AHSCT)recipients is not clearly known. We report 3 AHSCT recipients that were infected with influenza A (H1N1). Each of thepatients had a different hematological disease and was at a different post-transplantation stages. All the patients weretreated with oseltamivir, and zanamivir was switched to oseltamivir in 1 patient. All the patients survived without anycomplications. The course of swine flu can vary and progress with bacterial or other viral infections in immunosuppressedpatients.

A prospective study of the factors shaping antibody responses to the AS03-adjuvanted influenza A/H1N1 vaccine in cancer outpatients

PURPOSE

To identify the determinants of antibody responses to adjuvanted influenza A/H1N1/09 vaccines in a cohort of cancer outpatients.

PATIENTS AND METHODS

Patients with cancer and controls were enrolled in a prospective single-center field study. Two doses of AS03-adjuvanted pandemic influenza vaccine were administered to patients and one dose was administered to controls. Antibody responses were measured using hemagglutination inhibition and confirmed by microneutralization. Geometric mean titers (GMTs) and seroprotection rates (defined as GMTs ≥40) were compared.

RESULTS

Immunizations were safe and well tolerated in 197 cancer patients (lymphoma, 57; glioma, 26; lung or head and neck, 37; gastrointestinal, 41; breast, 36) and 138 controls. Similar seroprotection rates (82.3% versus 87%) and GMTs (336.9 versus 329.9) were achieved after two doses of adjuvanted vaccine in cancer patients and one dose in controls. Univariate analyses identified older age, prior immunization against seasonal influenza, lymphoma, CD4 count, active chemotherapy, and rituximab and steroid treatments as being associated with weaker antibody responses. However, only age and chemotherapy plus rituximab remained independent determinants of vaccine responses in multivariate analyses.

CONCLUSIONS

Two doses of AS03-adjuvanted influenza vaccine elicited potent antibody responses in most cancer patients despite ongoing chemotherapy, with the exception of rituximab-induced B-cell depletion. Oncology patients treated in an outpatient setting benefit from preventive vaccination against influenza with adjuvanted vaccines.

Immune response to 2009 pandemic H1N1 influenza virus A monovalent vaccine in children with cancer

PURPOSE

This study investigated the immune response to 2009 pandemic H1N1 influenza monovalent vaccine in children with cancer receiving chemotherapy.

METHODS

We enrolled 25 pediatric patients. Ten patients younger than 10 years old received two vaccinations and the remaining 15 patients older than 10 years old received one. We checked hemagglutination-inhibition (HAI) antibody titers in sera of patients before and 3-4 weeks after vaccination. Seroprotective titer was defined as HAI antibody titer ≥ 40 and seroresponse as ≥ 4-fold increase in HAI antibody titers after vaccination.

RESULTS

The pre- and post-vaccination seroprotective rates were 52% and 72% (P = 0.24). Sixteen (64%) patients were possibly exposed to 2009 pandemic H1N1 influenza previously, and there was significant association between possible exposure and pre-vaccination seroprotective rate (P = 0.03). Post-vaccination seroresponse rate was 32%, and seroresponse was greater in patients without pre-vaccination seroprotective titer than those with pre-vaccination seroprotective titer (50% vs. 15%, P = 0.07). Children with lymphocyte counts above 1,500/µl during vaccination period had better seroresponse than those with lymphocyte counts below 1,500/µl (P = 0.008). Post-vaccination geometric mean titer (GMT) significantly increased in patients younger than 10 years receiving two vaccinations (pre- and post-vaccination GMT were 21.4 and 60.6, respectively; P = 0.025).

CONCLUSIONS

Monovalent vaccine for the 2009 pandemic H1N1 influenza A was found to be partially immunogenic in children with cancer, as evidenced by 32% of seroresponse rate. Immune response can be improved with vaccinations administered to patients whose absolute lymphocyte counts returned to a level of 1,500/µl or higher.

Pandemic H1N1 influenza A viral infection complicated by atypical hemolytic uremic syndrome and diffuse alveolar hemorrhage

We report here on a case of a 27-year-old man with atypical hemolytic uremic syndrome and diffuse alveolar hemorrhage associated with influenza A H1N1 infection. Treatment with oseltamivir, plasma exchange and hemodiafiltration for the hemolytic uremic syndrome and meticulous supportive care with steroid pulse therapy for the pulmonary alveolar hemorrhage was successful in this case. We discuss the relationship between hemolytic uremic syndrome and influenza A and the underlying immunologic factors that should be tested in a patient with atypical hemolytic uremic syndrome. We also discuss using steroid therapy for patients with H1N1-related diffuse alveolar hemorrhage.

Severe H1N1-associated acute respiratory failure in immunocompromised children

BACKGROUND

Severe pandemic influenza A (H1N1) infection can lead to acute respiratory failure (ARF) with associated high mortality. Children with malignancy may be at higher risk of H1N1-associated ARF because of underlying primary disease or immunosuppression associated with chemotherapy.

PROCEDURE

We describe the clinical course and outcome of critically ill pediatric oncology/hematology patients with H1N1-associated ARF.

RESULTS

Five patients were admitted to the St. Jude Children's Research Hospital (SJCRH) ICU with H1N1 infection during the 2009-2010 influenza season. Underlying diagnoses included 2 patients with acute lymphoblastic leukemia and one each with neuroblastoma, brainstem glioma, and hemolytic anemia secondary to pyruvate kinase deficiency. All patients were mechanically ventilated secondary to ARF following unsuccessful trials of non-invasive ventilatory support. The majority of patients (4/5) required inotropic support, and none required dialysis. Further measures to support their ARF included high frequency oscillatory ventilation in 2 patients, nitric oxide in 3 patients, and surfactant in 1 patient. Three patients had bronchopleural air leak. All patients received oseltamivir; however, 2 were switched to intravenous zanamivir once resistance to oseltamivir was documented. Mean duration of mechanical ventilation was 24 ± 6.8 days and mean duration of ICU admission was 37 ± 12 days. All patients survived to hospital discharge.

CONCLUSION

Our series suggests an overall favorable outcome in immunocompromised children with H1N1-related ARF. Our experience underscores the value of aggressive support during H1N1-related ARF, and early detection and management of oseltamivir-resistant H1N1 infection in this high-risk population.

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.

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.

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.

Novel influenza A (H1N1) 2009 infection in the pediatric patients with hematologic and oncologic diseases in the Yeungnam region

Purpose

Natural history and consequences of the novel 2009 influenza A H1N1 (2009 H1N1) infection in immunocompromised pediatric patients are not yet fully understood. In this study, we investigated the clinical features and outcomes of the 2009 H1N1 infection in pediatric patients with hematological and oncological diseases.

Methods

We retrospectively reviewed the medical records of 528 patients who had hematological and oncological diseases and who were treated at 7 referral centers located in the Yeungnam region. Among the 528 patients, 27 with definite diagnosis of 2009 H1N1 infection were the subjects of this study. All patients were divided into the following 3 groups: patients who were receiving chemotherapy (group 1), patients who were immunosuppressed due to a non-malignant hematological disease (group 2), and patients who were off chemotherapy and had undergone their last chemotherapy course within 2 years from the influenza A pandemic (group 3).

Results

All 28 episodes of 2009 H1N1 infection were treated with the antiviral agent oseltamivir (Tamiflu®), and 20 episodes were treated after hospitalization. Group 1 patients had higher frequencies of lower respiratory tract infection and longer durations of fever and hospitalization as compared to those in group 2. Ultimately, all episodes resolved completely with no complications.

Conclusion

These results suggest that early antiviral therapy did not influence the morbidity or mortality of pediatric patients with hematological and oncological diseases in the Yeungnam region of Korea after the 2009 H1N1 infection. However, no definite conclusions can be drawn because of the small sample size.

Serological response to the 2009 pandemic influenza A (H1N1) virus for disease diagnosis and estimating the infection rate in Thai population

Background

Individuals infected with the 2009 pandemic virus A(H1N1) developed serological response which can be measured by hemagglutination-inhibition (HI) and microneutralization (microNT) assays.

Methodology/Principal Findings

MicroNT and HI assays for specific antibody to the 2009 pandemic virus were conducted in serum samples collected at the end of the first epidemic wave from various groups of Thai people: laboratory confirmed cases, blood donors and health care workers (HCW) in Bangkok and neighboring province, general population in the North and the South, as well as archival sera collected at pre- and post-vaccination from vaccinees who received influenza vaccine of the 2006 season. This study demonstrated that goose erythrocytes yielded comparable HI antibody titer as compared to turkey erythrocytes. In contrast to the standard protocol, our investigation found out the necessity to eliminate nonspecific inhibitor present in the test sera by receptor destroying enzyme (RDE) prior to performing microNT assay. The investigation in pre-pandemic serum samples showed that HI antibody was more specific to the 2009 pandemic virus than NT antibody. Based on data from pre-pandemic sera together with those from the laboratory confirmed cases, HI antibody titers ≥40 for adults and ≥20 for children could be used as the cut-off level to differentiate between the individuals with or without past infection by the 2009 pandemic virus.

Conclusions/Significance

Based on the cut-off criteria, the infection rates of 7 and 12.8% were estimated in blood donors and HCW, respectively after the first wave of the 2009 influenza pandemic. Among general population, the infection rate of 58.6% was found in children versus 3.1% in adults.

H1N1pdm influenza infection in hospitalized cancer patients: clinical evolution and viral analysis

Background

The novel influenza A pandemic virus (H1N1pdm) caused considerable morbidity and mortality worldwide in 2009. The aim of the present study was to evaluate the clinical course, duration of viral shedding, H1N1pdm evolution and emergence of antiviral resistance in hospitalized cancer patients with severe H1N1pdm infections during the winter of 2009 in Brazil.

Methods

We performed a prospective single-center cohort study in a cancer center in Rio de Janeiro, Brazil. Hospitalized patients with cancer and a confirmed diagnosis of influenza A H1N1pdm were evaluated. The main outcome measures in this study were in-hospital mortality, duration of viral shedding, viral persistence and both functional and molecular analyses of H1N1pdm susceptibility to oseltamivir.

Results

A total of 44 hospitalized patients with suspected influenza-like illness were screened. A total of 24 had diagnosed H1N1pdm infections. The overall hospital mortality in our cohort was 21%. Thirteen (54%) patients required intensive care. The median age of the studied cohort was 14.5 years (3–69 years). Eighteen (75%) patients had received chemotherapy in the previous month, and 14 were neutropenic at the onset of influenza. A total of 10 patients were evaluated for their duration of viral shedding, and 5 (50%) displayed prolonged viral shedding (median 23, range = 11–63 days); however, this was not associated with the emergence of a resistant H1N1pdm virus. Viral evolution was observed in sequentially collected samples.

Conclusions

Prolonged influenza A H1N1pdm shedding was observed in cancer patients. However, oseltamivir resistance was not detected. Taken together, our data suggest that severely ill cancer patients may constitute a pandemic virus reservoir with major implications for viral propagation.