Immunosuppressed patients with pandemic influenza A 2009 (H1N1) virus infection

Monkeypox (mpox) in immunosuppressed patients

The World Health Organization (WHO) proclaimed a public health emergency in July 2022 due to the emergence of Mpox (formerly monkeypox) while the globe was still dealing with the COVID-19 epidemic. The characteristics of mpox in immunocompetent individuals are well-characterized, despite difficulties in diagnostics, immunization, and access to treatment that persist in low-income countries. Patients with weakened immune systems are more likely to spread an illness and die from it than healthy people because they cannot mount a protective immune response against it, such as a neutralizing IgG and poxvirus-specific Th1 response. A health warning on severe mpox in people who are immunocompromised due to Human Immunodeficiency virus (HIV) and other illnesses was released by the U.S. Centers for Disease Control and Prevention (CDC) on September 29, 2022. The advice does not specifically include primary immunodeficiency, but it does define other immunocompromising disorders as “having autoimmune disease with immunodeficiency as a clinical component”. Both those with healthy immune systems and those with weakened immune systems, such as those who are immunosuppressed, older people, children, etc., have encountered serious health issues, but the latter group is more likely to do so. According to the advisory, “of the people with severe mpox manifestations for whom CDC has been consulted, the majority have had HIV with CD4 counts 200 cells/ml, indicating substantial immunosuppression”. However, new cases are still expected to be discovered, especially in low-income countries with limited access to diagnosis, treatment, and prevention, and where a large percentage of the mpox-infected population also has advanced HIV infection. Thus, further research is always needed to determine the best way to treat mpox in immunocompromised people. In this context, we discussed /reviewed the mpox clinical presentation, available treatment options and current preventive guidelines in immunocompromised patients.

Monkeypox (mpox) in immunosuppressed patients

The World Health Assembly declared that smallpox had been completely eradicated from the human population in 1980. Monkeypox, a zoonosis native to damp forested regions in West and Central Africa, is the illness that is most comparable to smallpox clinically and immunologically. Both illnesses could be prevented by the smallpox vaccine. Although the monkeypox virus is a less effective human disease than the smallpox virus, it could now spread among human populations if smallpox had not been eradicated and population-wide immunity had not been developed. A health warning on severe monkeypox in people who are immunocompromised due to Human Immunodeficiency virus (HIV) and other illnesses was released by the U.S. Centers for Disease Control and Prevention (CDC) on September 29, 2022. The advise does not specifically include primary immunodeficiency, but it does define other immunocompromising disorders as “having autoimmune disease with immunodeficiency as a clinical component”. The documented severe signs of monkeypox include widespread rashes with secondary fungal or bacterial skin infections or tissue death (necrosis), intestine obstruction, and difficulties with the heart, lungs, urinary system, and nervous system. Both those with healthy immune systems and those with weakened immune systems, such as those who are immunosuppressed, older people, children, etc., have encountered serious health issues, but the latter group is more likely to do so. According to the advisory, “of the people with severe monkeypox manifestations for whom CDC has been consulted, the majority have had HIV with CD4 counts 200 cells/ml, indicating substantial immunosuppression”. The current article goes into great detail about monkeypox disease occurring in immunocompromised patients and preventive guidelines.

Clinical features and outcome of influenza pneumonia in critically-ill immunocompromised patients

Immunocompromised subjects are at risk of severe viral infections which may require intensive care unit (ICU) admission. Data on the outcome of influenza pneumonia in critically-ill immunocompromised subjects are limited. We conducted a single-center observational study. All subjects admitted to the ICU for influenza pneumonia between 2016 and 2020 were included. The main objective was to compare the clinical features and outcome of critically-ill subjects with flu according to their immune status. 137 subjects (age 60 years-old, 58.4% male) were included, of whom 58 (42.34%) were intubated during the ICU stay. Forty-three (31.4%) subjects were immunocompromised. Immunocompromised subjects had a higher Charlson comorbidity index. In contrast, severity scores and hypoxemia at ICU admission, and ventilatory support during ICU stay were similar between the 2 groups. There was no difference in the rate of co-infections and ventilator-associated pneumonia between the 2 groups. Among intubated subjects, 10 (23.26%) immunocompromised subjects developed severe acute respiratory distress syndrome compared to 13 (13.83%) non-immunocompromised (P = .218). ICU mortality was 13.97%, with mortality being 3-times higher in immunocompromised subjects (25.58% vs 8.6%, P = .015). On multivariable analysis, immunocompromised status, higher age and lower arterial oxygen partial pressure/fraction of inspired oxygen were associated with an increased ICU mortality. Immunocompromised subjects with severe influenza pneumonia were more likely to develop severe acute respiratory distress syndrome and had a 3-fold increase in ICU mortality compared to non-immunocompromised subjects. Such difference was not explained by an increased rate of co-infections or nosocomial pneumonia, suggesting that influenza virus was by itself responsible of a more severe form of pulmonary disease in immunocompromised subjects.

Pre-existing Hemagglutinin Stalk Antibodies Correlate with Protection of Lower Respiratory Symptoms in Flu-Infected Transplant Patients

Hemagglutination-inhibitory antibodies are usually highly strain specific with little effect on infection with drifted or shifted strains. The significance of broadly cross-reactive non-HAI anti-influenza antibodies against conserved domains of virus glycoproteins, such as the hemagglutinin (HA) stalk, is of great interest. We characterize a cohort of 40 H1N1pmd09 influenza-infected patients and identify lower respiratory symptoms (LRSs) as a predictor for development of pneumonia. A binomial logistic regression of log10 pre-existing antibody values shows that the probability of LRS occurrence decreased with increased anti-HA full-length and stalk antibody ELISA titers. However, a multilevel logistic regression model adjusted by other potential serocorrelates demonstrates that only antibodies directed against the stalk of HA correlate with protection from lower respiratory infection, limiting disease progression. Our predictive model indicates that a threshold of protective immunity based on broadly cross-reactive HA stalk antibodies could be feasible.

Epidemic and pandemic viral infections: impact on tuberculosis and the lung: A consensus by the World Association for Infectious Diseases and Immunological Disorders (WAidid), Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases Study Group for Mycobacterial Infections (ESGMYC)

Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Clinical Course, Imaging Features, and Outcomes of COVID-19 in Kidney Transplant Recipients

Coronavirus disease 2019 (COVID-19) is a novel and highly contagious disease caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Older adults and patients with comorbidities and immunosuppressive conditions may experience severe signs and symptoms that can lead to death. This case series assesses the clinical course, imaging features, and outcomes for 12 patients with COVID-19 and a history of kidney transplantation. Patients were evaluated for symptoms, laboratory data, imaging findings, and outcomes from February 2020 to April 2020. Fever, cough, and dyspnea were the most common clinical symptoms, noted in 75% (nine/12), 75% (nine/12), and 41.7% (five/12) of the patients, respectively. Most of the patients had a normal white blood cell count, while 33.3% (four/12) had leukopenia and 8.3% (one/12) had leukocytosis. A combination of consolidation and ground glass opacity was the most predominant (75%) pattern of lung involvement on computed tomography (CT). Eight patients died of severe COVID-19 pneumonia and acute respiratory distress syndrome and four were discharged. All recovered cases had a unilateral peripheral pattern of involvement limited to only one zone on initial chest CT. It seems that CT imaging has an important role in predicting COVID-19 outcomes for solid organ transplant recipients. Future studies with long-term follow up and more cases are needed to elucidate COVID-19 diagnosis, outcome, and management strategies for these patients.

Influenza in patients with cancer after 2009 pandemic AH1N1: An 8-year follow-up study in Mexico

BACKGROUND

Immunosupressed patients are at high risk of influenza-related complications. Influenza AH1N1 has been hypothesized to induce worse outcomes in patients with malignancies, but after the A(H1N1)pdm09 few publications have analyzed the presentation and complications related to influenza afterward.

OBJECTIVES

We aimed to describe the characteristics, risk factors, and outcomes of influenza in an oncologic center after the 2009 pandemic and to compare our case distribution to the National community acquired influenza databases in Mexico and the United States.

METHODS

We reviewed the cases of confirmed influenza in patients with cancer from an oncological center in Mexico from April 2009 to April 2017. Data on severity and influenza type, malignancy, comorbidities, and outcomes were recorded. We correlated data between the Centers for Disease Control and Prevention (CDC) in the United States and SISVEFLU (Influenza Surveillance Program) in Mexico.

RESULTS

One hundred eighty-eight patients were included; 75 (39.9%) had a solid neoplasm and 113 (60.1%) had hematologic malignancies. AH1N1 was the most frequent influenza type (54.2%). Patients with hematologic malignancies had more pneumonia (55% vs 25%, P < .001), needed more hospitalizations (75% vs 39% P < .001), had higher all-cause mortality at 30 days (20% vs 9% P = .048) and influenza-associated mortality (17% vs 7% P = .041). Thirty (16%) patients died within 30 days, and 24 (12.7%) were related to influenza. Influenza type was not associated with worse outcomes. Yearly occurrence of influenza reported by the CDC and SISVEFLU showed a significant correlation (ρ = 0.823, P = .006).

CONCLUSIONS

AH1N1 was the dominant serotype. Patients with hematologic malignancies had more severe influenza and presented worse outcomes. Annual SISVEFLU and CDC surveillance information showed a similar distribution of cases along time but influenza serotypes did not match for all seasons.

Humoral response to natural influenza infection in solid organ transplant recipients

The humoral immune response of transplant recipients to influenza vaccination has been studied in detail. In contrast, the hemagglutinin inhibiting (HI) antibody response evoked by natural influenza infection and its impact on viral kinetics is unknown. In this prospective, multicenter, cohort study of natural influenza infection in transplant recipients, we measured HI antibody titers at presentation and 4 weeks later. Serial nasopharyngeal viral loads were determined using a quantitative influenza A polymerase chain reaction (PCR). We analyzed 196 transplant recipients with influenza infection. In the cohort of organ transplant patients with influenza A (n = 116), seropositivity rates for strain-specific antibodies were 44.0% (95% confidence interval [CI] 31.5-53.2%) at diagnosis and 64.7% (95% CI 55.4-72.9%) 4 weeks postinfection. Seroconversion was observed in 32.8% (95% CI 24.7-41.9%) of the cases. Lung transplant recipients were more likely to seroconvert (P = .002) and vaccine recipients were less likely to seroconvert (P = .024). A subset of patients (n = 30) who were unresponsive to prior vaccination were also unresponsive to natural infection. There was no correlation between viral kinetics and antibody response. This study provides novel data on the seroresponse to influenza infection in transplant patients and its relationship to a number of parameters including a prior vaccination status, virologic measures, and clinical variables.

Vaccines in pediatric transplant recipients-Past, present, and future

Infections significantly impact outcomes for solid organ and hematopoietic stem cell transplantation in children. Vaccine-preventable diseases contribute to morbidity and mortality in both early and late posttransplant time periods. Several infectious diseases and transplantation societies have published recommendations and guidelines that address immunization in adult and pediatric transplant recipients. In many cases, pediatric-specific studies are limited in size or quality, leading to recommendations being based on adult data or mixed adult-pediatric studies. We therefore review the current state of evidence for selected immunizations in pediatric transplant recipients and highlight areas for future investigation. Specific attention is given to studies that enrolled only children.

Clinical characteristics, evolution, and treatment-related risk factors for mortality among immunosuppressed patients with influenza A (H1N1) virus admitted to the intensive care unit

PURPOSE

Information about immunocompromised patients infected with influenza A (H1N1) virus and requiring admission to the ICU is lacking. Our objective was to know the clinical characteristics of these patients and to identify treatment-related variables associated with mortality.

MATERIAL AND METHODS

A prospective multicenter observational cohort study was based on data from a Spanish registry (2009-2015) collected by 148 Spanish ICUs. All patients admitted to the ICU with the diagnosis of influenza A (H1N1) virus infection were included. Immunosuppression was clearly defined. Factors associated with mortality in immunocompromised patients were assessed by conventional logistic regression analysis and by a propensity score (PS) adjusted-multivariable analysis.

RESULTS

Of 1899 patients with influenza A (H1N1) infection, 238 (12.5%) were classified as immunocompromised. Mortality was significantly higher in immunosuppressed patients. Four variables independently associated with mortality were identified: SOFA score, need of vasopressor, use of corticosteroids, and acute renal failure, AKIN 3 stage. In the PS-adjusted model, corticosteroid therapy remained as an independent factor associated with increased mortality (OR 2.25;95%CI, 1.15-4.38;p = 0.017). In the subgroup of hematological patients (n = 141), corticosteroid therapy was also associated with increased mortality (OR 3.12; 95%CI, 1.32-7.41; p = 0.010).

CONCLUSION

Immunocompromised individuals with influenza A (H1N1) admitted to the ICU have a poor outcome. In this population, the use of corticosteroids is strongly discouraged.

Possible explanations for why some countries were harder hit by the pandemic influenza virus in 2009 - a global mortality impact modeling study

BACKGROUND

A global pandemic mortality study found prominent regional mortality variations in 2009 for Influenza A(H1N1)pdm09. Our study attempts to identify factors that explain why the pandemic mortality burden was high in some countries and low in others.

METHODS

As a starting point, we identified possible risk factors worth investigating for Influenza A(H1N1)pdm09 mortality through a targeted literature search. We then used a modeling procedure (data simulations and regression models) to identify factors that could explain differences in respiratory mortality due to Influenza A(H1N1)pdm09. We ran sixteen models to produce robust results and draw conclusions. In order to assess the role of each factor in explaining differences in excess pandemic mortality, we calculated the reduction in between country variance, which can be viewed as an effect-size for each factor.

RESULTS

The literature search identified 124 publications and 48 possible risk factors, of which we were able to identify 27 factors with appropriate global datasets. The modelling procedure indicated that age structure (explaining 40% of the mean between country variance), latitude (8%), influenza A and B viruses circulating during the pandemic (3-8%), influenza A and B viruses circulating during the preceding influenza season (2-6%), air pollution (pm10; 4%) and the prevalence of other infections (HIV and TB) (4-6%) were factors that explained differences in mortality around the world. Healthcare expenditure, levels of obesity, the distribution of antivirals, and air travel did not explain global pandemic mortality differences.

CONCLUSIONS

Our study found that countries with a large proportion of young persons had higher pandemic mortality rates in 2009. The co-circulation of influenza viruses during the pandemic and the circulation of influenza viruses during the preceding season were also associated with pandemic mortality rates. We found that real time assessments of 2009 pandemic mortality risk factors (e.g. obesity) probably led to a number of false positive findings.

Travel vaccination recommendations and endemic infection risks in solid organ transplantation recipients

BACKGROUND

Solid organ transplant (SOT) recipients are often heavily immunosuppressed and consequently at risk of serious illness from vaccine preventable viral and bacterial infections or with endemic fungal and parasitic infections. We review the literature to provide guidance regarding the timing and appropriateness of vaccination and pathogen avoidance related to the immunological status of SOT recipients.

METHODS

A PUBMED search ([Vaccination OR vaccine] AND/OR ["specific vaccine"] AND/OR [immunology OR immune response OR cytokine OR T lymphocyte] AND transplant was performed. A review of the literature was performed in order to develop recommendations on vaccination for SOT recipients travelling to high-risk destinations.

RESULTS

Whilst immunological failure of vaccination in SOT is primarily the result of impaired B-cell responses, the role of T-cells in vaccine failure and success remains unknown. Vaccination should be initiated at least 4 weeks prior to SOT or more than 6 months post-SOT. Avoidance of live vaccination is generally recommended, although some live vaccines may be considered in the specific situations (e.g. yellow fever). The practicing physician requires a detailed understanding of region-specific endemic pathogen risks.

CONCLUSIONS

We provide a vaccination and endemic pathogen guide for physicians and travel clinics involved in the care of SOT recipients. In addition, recommendations based on timing of anticipated immunological recovery and available evidence regarding vaccine immunogenicity in SOT recipients are provided to help guide pre-travel consultations.

Translational research on influenza virus infection using a nonhuman primate model

Influenza virus infection is a seasonal infectious disease for humans, whereas it is also a zoonosis that is originally transmitted from animals to humans. Therefore, several animal models are used in research on influenza virus infection. We have used a nonhuman primate (NHP) model to extrapolate pathogenicity of various influenza viruses and efficacy of vaccines and antiviral drugs against the influenza viruses in humans. NHPs have genes, anatomical structure, and immune responses similar to those of humans as compared to other animal models. Using an NHP model, we revealed that the pandemic 2009 influenza A virus caused viral pneumonia as reported in human patients. Thus, it is thought that NHP models can be used to predict replication of emerging viruses in humans. We also examined the pathogenicity of highly pathogenic avian influenza viruses and evaluated a new therapeutic antibody in macaques under an immunocompromised condition. NHP models have provided promising results in research on other infectious diseases including Ebola virus and human/simian immunodeficiency virus infections. Thus, NHPs are important in biomedical research for determining the pathogenesis and for development of treatments, especially when clinical trials are difficult. We summarize the characteristics and advantages of research using NHP models in this review.

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.

Outcomes of influenza A(H1N1)pdm09 virus infection: results from two international cohort studies

BACKGROUND

Data from prospectively planned cohort studies on risk of major clinical outcomes and prognostic factors for patients with influenza A(H1N1)pdm09 virus are limited. In 2009, in order to assess outcomes and evaluate risk factors for progression of illness, two cohort studies were initiated: FLU 002 in outpatients and FLU 003 in hospitalized patients.

METHODS AND FINDINGS

Between October 2009 and December 2012, adults with influenza-like illness (ILI) were enrolled; outpatients were followed for 14 days and inpatients for 60 days. Disease progression was defined as hospitalization and/or death for outpatients, and hospitalization for >28 days, transfer to intensive care unit (ICU) if enrolled from general ward, and/or death for inpatients. Infection was confirmed by RT-PCR. 590 FLU 002 and 392 FLU 003 patients with influenza A (H1N1)pdm09 were enrolled from 81 sites in 17 countries at 2 days (IQR 1-3) and 6 days (IQR 4-10) following ILI onset, respectively. Disease progression was experienced by 29 (1 death) outpatients (5.1%; 95% CI: 3.4-7.2%) and 80 inpatients [death (32), hospitalization >28 days (43) or ICU transfer (20)] (21.6%; 95% CI: 17.5-26.2%). Disease progression (death) for hospitalized patients was 53.1% (26.6%) and 12.8% (3.8%), respectively, for those enrolled in the ICU and general ward. In pooled analyses for both studies, predictors of disease progression were age, longer duration of symptoms at enrollment and immunosuppression. Patients hospitalized during the pandemic period had a poorer prognosis than in subsequent seasons.

CONCLUSIONS

Patients with influenza A(H1N1)pdm09, particularly when requiring hospital admission, are at high risk for disease progression, especially if they are older, immunodeficient, or admitted late in infection. These data reinforce the need for international trials of novel treatment strategies for influenza infection and serve as a reminder of the need to monitor the severity of seasonal and pandemic influenza epidemics globally.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: FLU 002--NCT01056354, FLU 003--NCT01056185.

Changing face of vaccination in immunocompromised hosts

Infection prevention is a key component of care and an important determinant of clinical outcomes in a diverse population of immunocompromised hosts. Vaccination remains a fundamental preventative strategy, and clear guidelines exist for the vaccination of immunocompromised individuals and close contacts. Unfortunately, adherence to such guidelines is frequently suboptimal, with consequent missed opportunities to prevent infection. Additionally, vaccination of immunocompromised individuals is known to produce responses inferior to those observed in immunocompetent hosts. Multiple factors contribute to this finding, and developing improved vaccination strategies for those at high risk of infectious complications remains a priority of care providers. Herein, we review potential factors contributing to vaccine outcomes, focusing on host immune responses, and propose a means for applying modern, innovative systems biology technology to model critical determinants of vaccination success. With influenza vaccine in solid organ transplants used as a case in point, novel means for stratifying individuals using a host "immunophenotype" are explored, and strategies for individualizing vaccine approaches tailored to safely optimize vaccine responses in those most at risk are discussed.

HIV-1 and its gp120 inhibits the influenza A(H1N1)pdm09 life cycle in an IFITM3-dependent fashion

HIV-1-infected patients co-infected with A(H1N1)pdm09 surprisingly presented benign clinical outcome. The knowledge that HIV-1 changes the host homeostatic equilibrium, which may favor the patient resistance to some co-pathogens, prompted us to investigate whether HIV-1 infection could influence A(H1N1)pdm09 life cycle in vitro. We show here that exposure of A(H1N1)pdm09-infected epithelial cells to HIV-1 viral particles or its gp120 enhanced by 25% the IFITM3 content, resulting in a decrease in influenza replication. This event was dependent on toll-like receptor 2 and 4. Moreover, knockdown of IFITM3 prevented HIV-1 ability to inhibit A(H1N1)pdm09 replication. HIV-1 infection also increased IFITM3 levels in human primary macrophages by almost 100%. Consequently, the arrival of influenza ribonucleoproteins (RNPs) to nucleus of macrophages was inhibited, as evaluated by different approaches. Reduction of influenza RNPs entry into the nucleus tolled A(H1N1)pdm09 life cycle in macrophages earlier than usual, limiting influenza's ability to induce TNF-α. As judged by analysis of the influenza hemagglutin (HA) gene from in vitro experiments and from samples of HIV-1/A(H1N1)pdm09 co-infected individuals, the HIV-1-induced reduction of influenza replication resulted in delayed viral evolution. Our results may provide insights on the mechanisms that may have attenuated the clinical course of Influenza in HIV-1/A(H1N1)pdm09 co-infected patients during the recent influenza form 2009/2010.

Detection of the influenza A(H1N1)pdm09 virus carrying the K-15E, P83S and Q293H mutations in patients who have undergone bone marrow transplant

The 2009 pandemic influenza A(H1N1)pdm09 virus emerged and caused considerable morbidity and mortality in the third world, especially in Brazil. Although circulating strains of A(H1N1)pdm09 are A/California/04/2009-like (CA-04-like) viruses, various studies have suggested that some mutations in the viral hemagglutinin (HA) may be associated with enhanced severity and fatality. This phenomenon is particularly challenging for immunocompromised individuals, such as those who have undergone bone marrow transplant (BMT), because they are more likely to display worse clinical outcomes to influenza infection than non-immunocompromised individuals. We studied the clinical and viral aspects of post-BMT patients with confirmed A(H1N1)pdm09 diagnosis in the largest cancer hospital in Brazil. We found a viral strain with K-15E, P83S and Q293H polymorphisms in the HA, which is presumably more virulent, in these individuals. Despite that, these patients showed only mild symptoms of infection. Our findings complement the discovery of mild cases of infection with the A(H1N1)pdm09 virus with the K-15E, P83S and Q293H mutations in Brazil and oppose other studies that have linked these changes with increased disease severity. These results could be important for a better comprehension of the impact of the pandemic influenza in the context of BMT.

The impact of influenza A(H1N1)pdm09 infection on immunosuppressed patients

Before the advent of the influenza A(H1N1)pdm virus in 2009, the information available about the clinical manifestations and prognosis of influenza in immunosuppressed patients was scarce. With the 2009 pandemic, knowledge of the behavior, severity and importance of antiviral therapy for influenza A infection in immunocompromised hosts has increased considerably. The aim of the present manuscript is to review the main challenges of influenza in the most representative immunosuppressed populations such as solid organ transplant recipients, hematopoietic stem cell transplant recipients, patients with solid and hematological cancer and human immunodeficiency virus infected patients.

Changes in severity of influenza A(H1N1)pdm09 infection from pandemic to first postpandemic season, Germany

We studied risk factors for a severe clinical outcome in hospitalized patients with laboratory-confirmed influenza A(H1N1)pdm09 infection at the University Hospital Heidelberg in the pandemic and first postpandemic seasons. We identified 102 patients in 2009–10 and 76 in 2010–11. The proportion of severely diseased patients dramatically increased from 14% in 2009–10 to 46% in 2010–11 as did the mortality rate (5%–12%). Patients in the first postpandemic season were significantly older (38 vs. 18 years) and more frequently had underlying medical conditions (75% vs. 51%). Overall, 50 patients (28%) had a severe clinical outcome, resulting in 14 deaths. Multivariate analysis showed that older male patients with chronic lung disease were at increased risk for a severe clinical outcome. In summary, the proportion of patients with severe disease and fatal cases increased in the postpandemic season. Therefore, patients with suspected infections should be promptly identified and receive early treatment.

Respiratory tract infections in the immunocompromised

PURPOSE OF REVIEW

Pulmonary infections are particularly common in the immunosuppressed host. This review discusses emerging threats, newer modalities of diagnostic tests and emerging treatment options, and also highlights the increasing problem of antimicrobial resistance.

RECENT FINDINGS

Nosocomial pneumonia is increasingly due to multidrug-resistant Gram-negative organisms in immunosuppressed patients. Viral pneumonias remain a very significant threat, present atypically and carry a high mortality. Aspergillosis remains the most common fungal infection, and infections due to Mucorales are increasing. Multidrug-resistant tuberculosis is on the increase throughout the world. Mixed infections are common and early bronchoscopy with appropriate microbiological tests, including molecular diagnostics, optimise management and reduce mortality.

CONCLUSION

Pulmonary infection remains the most frequent infectious complication in the immunocompromised host. These complex infections are often mixed, have atypical presentations and can be due to multidrug-resistant organisms. Multidisciplinary involvement in specialist centres with appropriate diagnostics, treatment and infection control improves outcome. There is a desperate need for new antimicrobial agents active against Gram-negative pathogens.

Pathogenicity of pandemic H1N1 influenza A virus in immunocompromised cynomolgus macaques

Pandemic (H1N1) 2009 influenza virus spread throughout the world since most people did not have immunity against the virus. In the post pandemic phase when many humans might possess immunity against the pandemic virus, one of the concerns is infection in immunocompromised people. Therefore, we used an immunosuppressed macaque model to examine pathogenicity of the pandemic (H1N1) 2009 virus under an immunocompromised condition. The virus in nasal samples of immunosuppressed macaques infected with the pandemic (H1N1) 2009 virus was detected longer after infection than was the virus in nasal samples of immunocompetent macaques. As expected, not only virus amounts but also virus propagation sites in the immunosuppressed macaques were larger than those in lungs of the immunocompetent macaques when they were infected with the pandemic virus. Immunosuppressed macaques possessed low levels of immune cells producing cytokines and chemokines, but levels of inflammatory cytokines/chemokine interleukin (IL)-6, IL-18, and monocyte chemotactic protein (MCP)-1 in lungs of the immunosuppressed macaques were higher than those in lungs of the immunocompetent macaques, though the differences were not statistically significant. Therefore, under an immunosuppressive condition, the pandemic influenza (H1N1) 2009 virus might cause more severe morbidity with high cytokine/chemokine production by the host innate immune system than that seen in macaques under the immunocompetent condition.

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.

Higher memory responses in HIV-infected and kidney transplanted patients than in healthy subjects following priming with the pandemic vaccine

Background

Memory responses require immune competence. We assessed the influence of priming with AS03-adjuvanted pandemic vaccine (Pandemrix®) on memory responses of HIV patients, kidney recipients (SOT) and healthy controls (HC).

Method

Participants (HIV: 197, SOT: 53; HC: 156) were enrolled in a prospective study and 390/406 (96%) completed it. All had been primed in 2009/2010 with 1 (HC) or 2 (patients) doses of Pandemrix®, and were boosted with the 2010/2011 seasonal influenza vaccine. Geometric mean titres and seroprotection rates were measured 12 months after priming and 4 weeks after boosting. Primary and memory responses were directly compared in 191 participants (HCW: 69, HIV: 71, SOT: 51) followed during 2 consecutive seasons.

Results

Most participants (HC: 77.8%, HIV: 77.6%, SOT: 66%) remained seroprotected at 12 months post-priming. Persisting A/09/H1N1 titers were high in HIV (100.2) and HC (120.1), but lower in SOT (61.4) patients. Memory responses reached higher titers in HIV (507.8) than in HC (253.5) and SOT (136.9) patients. Increasing age and lack of HAART reduced persisting and memory responses, mainly influenced by residual antibody titers. Comparing 2009/2010 and 2010/2011 titers in 191 participants followed for 2 seasons indicated lower post-2010/2011 titers in HC (240.2 vs 313.9), but higher titers in HIV (435.7 vs 338.0) and SOT (136 vs 90.3) patients.

Conclusions

Priming with 2 doses of Pandemrix® elicited persistent antibody responses and even stronger memory responses to non-adjuvanted seasonal vaccine in HIV patients than 1 dose in healthy subjects. Adjuvanted influenza vaccines may improve memory responses of immunocompromised patients.

Trial Registration

ClinicalTrials.gov NCT01022905

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.