Influenza pandêmica A (H1N1) 2009: fatores de risco para o internamento

Influenza vaccination for elderly, vulnerable and high-risk subjects: a narrative review and expert opinion

Influenza is associated with a substantial health burden, especially in high-risk subjects such as older adults, frail individuals and those with underlying chronic diseases. In this review, we summarized clinical findings regarding the impact of influenza in vulnerable populations, highlighted the benefits of influenza vaccination in preventing severe illness and complications and reviewed the main evidence on the efficacy, effectiveness and safety of the vaccines that are best suited to older adults among those available in Italy. The adverse outcomes associated with influenza infection in elderly and frail subjects and those with underlying chronic diseases are well documented in the literature, as are the benefits of vaccination (mostly in older adults and in patients with cardiovascular diseases, diabetes and chronic lung disease). High-dose and adjuvanted inactivated influenza vaccines were specifically developed to provide enhanced immune responses in older adults, who generally have low responses mainly due to immunosenescence, comorbidities and frailty. These vaccines have been evaluated in clinical studies and systematic reviews by international immunization advisory boards, including the European Centre for Disease Prevention and Control. The high-dose vaccine is the only licensed influenza vaccine to have demonstrated greater efficacy versus a standard-dose vaccine in preventing laboratory-confirmed influenza in a randomized controlled trial. Despite global recommendations, the vaccination coverage in high-risk populations is still suboptimal. All healthcare professionals (including specialists) have an important role in increasing vaccination rates.

Robust and prototypical immune responses toward COVID-19 vaccine in First Nations peoples are impacted by comorbidities

High-risk groups, including Indigenous people, are at risk of severe COVID-19. Here we found that Australian First Nations peoples elicit effective immune responses to COVID-19 BNT162b2 vaccination, including neutralizing antibodies, receptor-binding domain (RBD) antibodies, SARS-CoV-2 spike-specific B cells, and CD4+ and CD8+ T cells. In First Nations participants, RBD IgG antibody titers were correlated with body mass index and negatively correlated with age. Reduced RBD antibodies, spike-specific B cells and follicular helper T cells were found in vaccinated participants with chronic conditions (diabetes, renal disease) and were strongly associated with altered glycosylation of IgG and increased interleukin-18 levels in the plasma. These immune perturbations were also found in non-Indigenous people with comorbidities, indicating that they were related to comorbidities rather than ethnicity. However, our study is of a great importance to First Nations peoples who have disproportionate rates of chronic comorbidities and provides evidence of robust immune responses after COVID-19 vaccination in Indigenous people.

A Bayesian belief network-based analytics methodology for early-stage risk detection of novel diseases

During a pandemic, medical specialists have substantial challenges in discovering and validating new disease risk factors and designing effective treatment strategies. Traditionally, this approach entails several clinical studies and trials that might last several years, during which strict preventive measures are enforced to manage the outbreak and limit the death toll. Advanced data analytics technologies, on the other hand, could be utilized to monitor and expedite the procedure. This research integrates evolutionary search algorithms, Bayesian belief networks, and innovative interpretation techniques to provide a comprehensive exploratory-descriptive-explanatory machine learning methodology to assist clinical decision-makers in responding promptly to pandemic scenarios. The proposed approach is illustrated through a case study in which the survival of COVID-19 patients is determined using inpatient and emergency department (ED) encounters from a real-world electronic health record database. Following an exploratory phase in which genetic algorithms are used to identify a set of the most critical chronic risk factors and their validation using descriptive tools based on the concept of Bayesian Belief Nets, the framework develops and trains a probabilistic graphical model to explain and predict patient survival (with an AUC of 0.92). Finally, a publicly available online, probabilistic decision support inference simulator was constructed to facilitate what-if analysis and aid general users and healthcare professionals in interpreting model findings. The results widely corroborate intensive and expensive clinical trial research assessments.

Influenza-associated hospitalisation and mortality rates among global Indigenous populations; a systematic review and meta-analysis

BACKGROUND

More than 50 million influenza infections and over 100,000 deaths from influenza occur annually. While Indigenous populations experience an inequitable influenza burden, the magnitude of this inequity has not previously been estimated on a global scale. This study compared rates of influenza-associated hospitalisation and mortality between Indigenous and non-Indigenous populations globally.

METHODS

A systematic review and meta-analysis was conducted including literature published prior to 13 July 2021. Eligible articles either reported a rate ratio (RR) comparing laboratory-confirmed influenza-associated hospitalisation and/or mortality between an Indigenous population and a corresponding benchmark population, or reported sufficient information for this to be calculated using publicly available data. Findings were reported by country/region and pooled by country and period (pandemic/seasonal) when multiple studies were available using a random-effects model. The I2 statistic assessed variability between studies.

RESULTS

Thirty-six studies (moderate/high quality) were included; all from high or high-middle income countries. The pooled influenza-associated hospitalisation RR (HRR) for indigenous compared to benchmark populations was 5·7 (95% CI: 2·7-12·0) for Canada, 5·2 (2.9-9.3) for New Zealand, and 5.2 (4.2-6.4) for Australia. Of the Australian studies, the pooled HRR for seasonal influenza was 3.1 (2·7-3·5) and for pandemic influenza was 6·2 (5·1-7·5). Heterogeneity was slightly higher among studies of pandemic influenza than seasonal influenza. The pooled mortality RR was 4.1 (3·0-5.7) in Australia and 3·3 (2.7-4.1) in the United States.

CONCLUSIONS

Ethnic inequities in severe influenza persist and must be addressed by reducing disparities in the underlying determinants of health. Influenza surveillance systems worldwide should include Indigenous status to determine the extent of the disease burden among Indigenous populations. Ethnic inequities in pandemic influenza illustrate the need to prioritise Indigenous populations in pandemic response plans.

Understanding the Role of HLA Class I Molecules in the Immune Response to Influenza Infection and Rational Design of a Peptide-Based Vaccine

Influenza A virus is a respiratory pathogen that is responsible for regular epidemics and occasional pandemics that result in substantial damage to life and the economy. The yearly reformulation of trivalent or quadrivalent flu vaccines encompassing surface glycoproteins derived from the current circulating strains of the virus does not provide sufficient cross-protection against mismatched strains. Unlike the current vaccines that elicit a predominant humoral response, vaccines that induce CD8⁺ T cells have demonstrated a capacity to provide cross-protection against different influenza strains, including novel influenza viruses. Immunopeptidomics, the mass spectrometric identification of human-leukocyte-antigen (HLA)-bound peptides isolated from infected cells, has recently provided key insights into viral peptides that can serve as potential T cell epitopes. The critical elements required for a strong and long-living CD8⁺ T cell response are related to both HLA restriction and the immunogenicity of the viral peptide. This review examines the importance of HLA and the viral immunopeptidome for the design of a universal influenza T-cell-based vaccine.

Respiratory Tract Infections in Diabetes - Lessons From Tuberculosis and Influenza to Guide Understanding of COVID-19 Severity

Patients with type-2 diabetes (T2D) are more likely to develop severe respiratory tract infections. Such susceptibility has gained increasing attention since the global spread of Coronavirus Disease 2019 (COVID-19) in early 2020. The earliest reports marked T2D as an important risk-factor for severe forms of disease and mortality across all adult age groups. Several mechanisms have been proposed for this increased susceptibility, including pre-existing immune dysfunction, a lack of metabolic flexibility due to insulin resistance, inadequate dietary quality or adverse interactions with antidiabetic treatments or common comorbidities. Some mechanisms that predispose patients with T2D to severe COVID-19 may indeed be shared with other previously characterized respiratory tract infections. Accordingly, in this review, we give an overview of response to Influenza A virus and to Mycobacterium tuberculosis (Mtb) infections. Similar risk factors and mechanisms are discussed between the two conditions and in the case of COVID-19. Lastly, we address emerging approaches to address research needs in infection and metabolic disease, and perspectives with regards to deployment or repositioning of metabolically active therapeutics.

From H1N1 to COVID-19: What we have seen in children with hemoglobinopathies

This work aimed to better understand the impact of pandemics of respiratory viruses on children with hemoglobinopathies through a comprehensive review of the literature. MEDLINE, SCIELO, LILACS, and PUBMED were used as data sources to find articles without time period restrictions. Previous observations suggest that patients with hemoglobinopathies are a group especially susceptible to the complications of viral respiratory infections, with greater morbidity and mortality related to them. Within this context, this review found that, during the 2009 H1N1 pandemic, the risk of hospitalization in children and adults increased, especially in patients with a history of complications such as acute chest syndrome. In addition, the Coronavirus Disease 2019 (COVID-19) pandemic appears to have less repercussion among children with hemoglobinopathies compared to adults, similar to what is seen in the general population. In the H1N1 pandemic, patients with hemoglobinopathies behaved as a group more susceptible to complications, with increased morbidity and mortality. However, for COVID-19, the existing data to date on these patients do not show the same clinical impact. Thus, although these children deserve attention in case of infection due to their potential risks, they seem to have a favorable evolution.

Social determinants of the disproportionately higher rates of COVID-19 infection among African Caribbean and Black (ACB) population: A systematic review protocol

The challenges of identifying and eliminating racial disparities regarding the exposure, transmission, prevention, and treatment of communicable diseases within the healthcare system have been a mounting concern since the COVID-19 pandemic began. The African, Caribbean, and Black (ACB) populations in Canada represent a fast-expanding and underprivileged community, which have been previously found to have higher susceptibility to communicable diseases and lower sensitivity to intervention measures. Currently, there is insufficient evidence to adequately identify racial patterns in the prevalence and healthcare utilization among the ACB population within the context of the ongoing pandemic. Our proposed study will explore the association between the social determinants of health (SDH) and COVID-19 health outcomes in ACB populations in high-income countries (UK, US, Australia, Canada). We will explore the current evidence through a systematic review of COVID-19 pandemic literature covering the period between December 2019 and October 2020. The objectives include investigating the effect of SDH on the ACB populations’ risk to COVID-19 health outcomes, including COVID-19 infection incidence, severity of disease, hospitalization, mortality and barriers to the treatment and management of COVID-19 for Black people in Canada. In addition, this project aims to investigate the effect of COVID-19 on ACB communities in Ontario by examining the challenges that front-line healthcare workers and administrators have during this pandemic as it pertains to service provisions to ACB communities. A systematic review of original and review studies will be conducted based on the publications on eleven databases (MEDLINE, Web of Science, Cochrane Library, CINAHL, NHS EDD, Global Health, PsychInfo, PubMed, Scopus, Proquest, and Taylor and Francis Online Journals) Primary outcomes will include the rate of COVID-19 infection. The systematic review will include a meta-analysis of available quantitative data, as well as a narrative synthesis of qualitative studies. This systematic review will be among the first to report racial disparities in COVID-19 infection among the ACB population in Canada. Through synthesizing population data regarding the risk factors on various levels, the findings from this systematic review will provide recommendations for future research and evidence for clinical practitioners and social workers. Overall, a better understanding of the nature and consequences of racial disparities during the pandemic will provide policy directions for effective interventions and resilience-building in the post-pandemic era.

The association between socioeconomic status and pandemic influenza: Systematic review and meta-analysis

BACKGROUND

The objective of this study is to document whether and to what extent there is an association between socioeconomic status (SES) and disease outcomes in the last five influenza pandemics.

METHODS/PRINCIPLE FINDINGS

The review included studies published in English, Danish, Norwegian and Swedish. Records were identified through systematic literature searches in six databases. We summarized results narratively and through meta-analytic strategies. Only studies for the 1918 and 2009 pandemics were identified. Of 14 studies on the 2009 pandemic including data on both medical and social risk factors, after controlling for medical risk factors 8 demonstrated independent impact of SES. In the random effect analysis of 46 estimates from 35 studies we found a pooled mean odds ratio of 1.4 (95% CI: 1.2-1.7, p < 0.001), comparing the lowest to the highest SES, but with substantial effect heterogeneity across studies,-reflecting differences in outcome measures and definitions of case and control samples. Analyses by pandemic period (1918 or 2009) and by level of SES measure (individual or ecological) indicated no differences along these dimensions. Studies using healthy controls tended to document that low SES was associated with worse influenza outcome, and studies using infected controls find low SES associated with more severe outcomes. A few studies compared severe outcomes (ICU or death) to hospital admissions but these did not find significant SES associations in any direction. Studies with more unusual comparisons (e.g., pandemic vs seasonal influenza, seasonal influenza vs other patient groups) reported no or negative non-significant associations.

CONCLUSIONS/SIGNIFICANCE

We found that SES was significantly associated with pandemic influenza outcomes with people of lower SES having the highest disease burden in both 1918 and 2009. To prepare for future pandemics, we must consider social vulnerability. The protocol for this study has been registered in PROSPERO (ref. no 87922) and has been published Mamelund et al. (2019).

CD8(+) T cell landscape in Indigenous and non-Indigenous people restricted by influenza mortality-associated HLA-A*24:02 allomorph

Indigenous people worldwide are at high risk of developing severe influenza disease. HLA-A*24:02 allele, highly prevalent in Indigenous populations, is associated with influenza-induced mortality, although the basis for this association is unclear. Here, we define CD8⁺ T-cell immune landscapes against influenza A (IAV) and B (IBV) viruses in HLA-A*24:02-expressing Indigenous and non-Indigenous individuals, human tissues, influenza-infected patients and HLA-A*24:02-transgenic mice. We identify immunodominant protective CD8⁺ T-cell epitopes, one towards IAV and six towards IBV, with A24/PB2_550-558-specific CD8⁺ T cells being cross-reactive between IAV and IBV. Memory CD8⁺ T cells towards these specificities are present in blood (CD27⁺CD45RA^- phenotype) and tissues (CD103⁺CD69⁺ phenotype) of healthy individuals, and effector CD27^-CD45RA^-PD-1⁺CD38⁺CD8⁺ T cells in IAV/IBV patients. Our data show influenza-specific CD8⁺ T-cell responses in Indigenous Australians, and advocate for T-cell-mediated vaccines that target and boost the breadth of IAV/IBV-specific CD8⁺ T cells to protect high-risk HLA-A*24:02-expressing Indigenous and non-Indigenous populations from severe influenza disease.

Virus Infections and Host Metabolism-Can We Manage the Interactions?

When viruses infect cells, they almost invariably cause metabolic changes in the infected cell as well as in several host cell types that react to the infection. Such metabolic changes provide potential targets for therapeutic approaches that could reduce the impact of infection. Several examples are discussed in this review, which include effects on energy metabolism, glutaminolysis and fatty acid metabolism. The response of the immune system also involves metabolic changes and manipulating these may change the outcome of infection. This could include changing the status of herpesviruses infections from productive to latency. The consequences of viral infections which include coronavirus disease 2019 (COVID-19), may also differ in patients with metabolic problems, such as diabetes mellitus (DM), obesity, and endocrine diseases. Nutrition status may also affect the pattern of events following viral infection and examples that impact on the pattern of human and experimental animal viral diseases and the mechanisms involved are discussed. Finally, we discuss the so far few published reports that have manipulated metabolic events in-vivo to change the outcome of virus infection. The topic is expected to expand in relevance as an approach used alone or in combination with other therapies to shape the nature of virus induced diseases.

National retrospective cohort study to identify risk factors for in-hospital 30-day lethality in laboratory-confirmed cases of influenza

OBJECTIVE

To identify factors associated with the risk of death in adolescent and adult inpatients with laboratory-positive (reverse-transcription polymerase chain reaction) influenza in Mexico during consecutive influenza seasons (2018-2020).

PATIENTS AND METHODS

A retrospective cohort study used national surveillance system data, enrolling 3422 individuals. The association between various risk factors and 30-day in-hospital lethality were evaluated through risk ratios (RR) and 95% confidence intervals (CI).

RESULTS

The lethality rate was 18.1%. Flu vaccination history (RR = 0.56, 95% CI 0.42-0.78), early antiviral drug administration (≤ two days from symptom onset [reference ≥ 5 days], RR = 0.68, 95% CI 0.58-0.81), and a history of asthma (RR = 0.66, 95% CI 0.47-0.95) showed protective effects against influenza-attributable death. Mechanical ventilator support produced the highest increase in death risk (RR = 3.31, 95% CI 2.89-3.79). Male sex, older age, AH1N1 subtype, and other chronic diseases were also associated with fatal in-hospital influenza-related outcomes.

CONCLUSIONS

Our findings highlight the major relevance of promoting immunization in high-risk individuals, together with ensuring early and effective antiviral management in suspected influenza cases.

National retrospective cohort study to identify risk factors for in-hospital 30-day lethality in laboratory-confirmed cases of influenza

OBJECTIVE

To identify factors associated with the risk of death in adolescent and adult inpatients with laboratory-positive (reverse-transcription polymerase chain reaction) influenza in Mexico during consecutive influenza seasons (2018-2020).

METHODS

A retrospective cohort study used national surveillance system data, enrolling 3.422 individuals. The association between various risk factors and 30-day in-hospital lethality were evaluated through risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

The lethality rate was 18.1%. Flu vaccination history (RR=0.56, 95% CI 0.42-0.78), early antiviral drug administration (≤2 days from symptom onset [reference ≥5 days], RR=0.68, 95% CI 0.58-0.81), and a history of asthma (RR=0.66, 95% CI 0.47-0.95) showed protective effects against influenza-attributable death. Mechanical ventilator support produced the highest increase in death risk (RR=3.31, 95% CI 2.89-3.79). Male sex, older age, AH1N1 subtype, and other chronic diseases were also associated with fatal in-hospital influenza-related outcomes.

CONCLUSIONS

Our findings highlight the major relevance of promoting immunization in high-risk individuals, together with ensuring early and effective antiviral management in suspected influenza cases.

Obesity Increases the Severity and Mortality of Influenza and COVID-19: A Systematic Review and Meta-Analysis

Since December 2019, COVID-19 has aroused global attention. Studies show the link between obesity and severe outcome of influenza and COVID-19. Thus, we aimed to compare the impacts of obesity on the severity and mortality of influenza and COVID-19 by performing a meta-analysis. A systematic search was performed in MEDLINE, EMASE, ClinicalTrials.gov, and Web of Science from January 2009 to July 2020. The protocol was registered onto PROSPERO (CRD42020201461). After selection, 46 studies were included in this meta-analysis. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were analyzed. We found obesity was a risk factor for the severity and mortality of influenza (ORsevere outcome = 1.56, CI: 1.28-1.90; ORmortality = 1.99, CI: 1.15-3.46). For COVID-19, obesity was a significant risk factor only for severe outcome (OR = 2.07, CI: 1.53-2.81) but not for mortality (OR = 1.57, CI: 0.85-2.90). Compared with obesity, morbid obesity was linked with a higher risk for the severity and mortality of both influenza (OR = 1.40, CI: 1.10-1.79) and COVID-19 (OR = 3.76, CI: 2.67-5.28). Thus, obesity should be recommended as a risk factor for the prognosis assessment of COVID-19. Special monitoring and earlier treatment should be implemented in patients with obesity and COVID-19.

Polymorphisms in Processing and Antigen Presentation-Related Genes and Their Association with Host Susceptibility to Influenza A/H1N1 2009 Pandemic in a Mexican Mestizo Population

(1) Background: The influenza A/H1N1 pdm09 virus rapidly spread throughout the world. Despite the inflammatory and virus-degradation pathways described in the pathogenesis of influenza A virus (IAV) infection, little is known about the role of the single nucleotide polymorphisms (SNPs) in the genes involved in the processing and antigenic presentation-related mechanisms. (2) Methods: In this case-control study, we evaluated 17 SNPs in five genes (TAP1, TAP2, TAPBP, PSMB8, and PSMB9). One hundred and twenty-eight patients with influenza A/H1N1 infection (INF-P) and 111 healthy contacts (HC) were included; all of them are Mexican mestizo. (3) Results: In allele and genotype comparison, the rs241433/C allele (TAP2), as well as AG haplotype (rs3763365 and rs4148882), are associated with reduced risk for influenza A/H1N1 infection (p < 0.05). On the other hand, the rs2071888G allele (TAPBP) and GG haplotype (rs3763365 and rs9276810) are associated with a higher risk for influenza A/H1N1 infection. In addition, after adjustment for covariates, the association to a reduced risk for influenza A/H1N1 infection remains with rs241433/C allele (p < 0.0001, OR = 0.24, 95% CI = 0.13-0.43), and the association with TAPBP is also maintained with the G allele (p = 0.0095, OR = 1.89, 95% CI = 1.17-3.06) and GG genotype models (p < 0.05, OR = 2.18, 95% CI = 1.27-3.74). (4) Conclusion: The rs241433/C allele and AC genotype (TAP2) and the AG haplotype are associated with a reduced risk for influenza A/H1N1 infection. In addition, the rs2071888/G allele and GG genotype (TAPBP) and the GG haplotype are associated with a higher risk for developing influenza A/H1N1 infection in a Mexican mestizo population.

Cost-Effectiveness Analysis of Influenza A (H1N1) Chemoprophylaxis in Brazil

Background: Oseltamivir and zanamivir are recommended for treating and preventing influenza A (H1N1) worldwide. In Brazil, this official recommendation lacks an economic evaluation. Our objective was to assess the efficiency of influenza A chemoprophylaxis in the Brazilian context.

Methods: We assessed the cost-effectiveness of oseltamivir and zanamivir for prophylaxis of influenza for high risk population, compared to no prophylaxis, in the perspective of Brazilian public health system. Quality-adjusted life years (QALY) and effectiveness data were based on literature review and costs in Brazilian real (BRL) were estimated from official sources and micro-costing of 2016’s H1N1 admissions at a university hospital. We used a decision-tree model considering prophylaxis and no prophylaxis and the probabilities of H1N1, ambulatory care, admission to hospital, intensive care, patient discharge, and death. Adherence and adverse events from prophylaxis were included. Incremental cost-effectiveness ratio was converted to 2016 United States dollar (USD). Uncertainty was assessed with univariated and probabilistic sensitivity analysis.

Results: Adherence to prophylaxis was 0.70 [95% confidence interval (CI) 0.54; 0.83]; adverse events, 0.09 (95% CI 0.02; 0.18); relative risk of H1N1 infection in chemoprophylaxis, 0.43 (95% CI 0.33; 0.57); incidence of H1N1, 0.14 (95% CI 0.11; 0.16); ambulatory care, 0.67 (95% CI 0.58; 0.75); hospital admission, 0.43 (CI 95% 0.39; 0.42); hospital mortality, 0.14 (CI 95% 0.12; 0.15); intensive care unit admission, 0.23 (95% CI 0.20; 0.27); and intensive care mortality, 0.40 (95% CI 0.29; 0.52). QALY in H1N1 state was 0.50 (95% CI 0.46; 0.53); in H1N1 inpatients, 0.23 (95% CI 0.18; 0.28); healthy, 0.885 (95% CI 0.879; 0.891); death, 0. Adverse events estimated to affect QALY in –0.185 (95% CI –0.290; –0.050). Cost for chemoprophylaxis was BRL 39.42 [standard deviation (SD) 17.94]; ambulatory care, BRL 12.47 (SD 5.21); hospital admission, BRL 5,727.59 (SD 7,758.28); intensive care admission, BRL 19,217.25 (SD 7,917.33); and adverse events, BRL 292.05 (SD 724.95). Incremental cost-effectiveness ratio was BRL –4,080.63 (USD –1,263.74)/QALY and –982.39 (USD –304.24)/H1N1 prevented. Results were robust to sensitivity analysis.

Conclusion: Chemoprophylaxis of influenza A (H1N1) is cost-saving in Brazilian health system context.

Recalling the Future: Immunological Memory Toward Unpredictable Influenza Viruses

Persistent and durable immunological memory forms the basis of any successful vaccination protocol. Generation of pre-existing memory B cell and T cell pools is thus the key for maintaining protective immunity to seasonal, pandemic and avian influenza viruses. Long-lived antibody secreting cells (ASCs) are responsible for maintaining antibody levels in peripheral blood. Generated with CD4⁺ T help after naïve B cell precursors encounter their cognate antigen, the linked processes of differentiation (including Ig class switching) and proliferation also give rise to memory B cells, which then can change rapidly to ASC status after subsequent influenza encounters. Given that influenza viruses evolve rapidly as a consequence of antibody-driven mutational change (antigenic drift), the current influenza vaccines need to be reformulated frequently and annual vaccination is recommended. Without that process of regular renewal, they provide little protection against “drifted” (particularly H3N2) variants and are mainly ineffective when a novel pandemic (2009 A/H1N1 “swine” flu) strain suddenly emerges. Such limitation of antibody-mediated protection might be circumvented, at least in part, by adding a novel vaccine component that promotes cross-reactive CD8⁺ T cells specific for conserved viral peptides, presented by widely distributed HLA types. Such “memory” cytotoxic T lymphocytes (CTLs) can rapidly be recalled to CTL effector status. Here, we review how B cells and follicular T cells are elicited following influenza vaccination and how they survive into a long-term memory. We describe how CD8⁺ CTL memory is established following influenza virus infection, and how a robust CTL recall response can lead to more rapid virus elimination by destroying virus-infected cells, and recovery. Exploiting long-term, cross-reactive CTL against the continuously evolving and unpredictable influenza viruses provides a possible mechanism for preventing a disastrous pandemic comparable to the 1918-1919 H1N1 “Spanish flu,” which killed more than 50 million people worldwide.

Rapid detection and clinical spectrum of the novel influenza H1N1 strain in a diabetic pediatric population

OBJECTIVES

H1N1 infection in diabetic patients is of special concern and serious interest since the virus can place individuals, especially children, at great possible risk of subsequently developing type 1 diabetes. This work aims to describe the demographic characteristics, clinical features, and severity of illness of children with type 1 diabetes mellitus (DM), compare the incidence of pandemic H1N1 virus in children with that of the general pediatric population with influenza-like symptoms, and identify the complications of H1N1 virus infection associated with glycemic control.

METHODS

The present study included 45 children and adolescents with type 1 diabetes, who were subject to clinical and laboratory investigations. Another 30 healthy adolescents and children with a mean age of 10.43 ± 4.38 years were included as a control group. H1N1 reverse-transcriptase quantitative PCR (RT-Q PCR) was tested for H1N1 virus detection.

RESULTS

Diabetic patients positive for (H1N1) showed significantly higher random blood sugar (RBS) levels than diabetic patients negative for (H1N1). Moreover, the H1N1-positive patients had significantly higher hemoglobin (Hb) g/dL, platelet counts, total leukocyte counts (TLCs), and CRP levels. Newly diagnosed patients who were tested positive for (H1N1) and diabetic ketoacidosis (DKA) had significantly higher RBS levels and TLCs than patients who were presented with hyperglycemia.

CONCLUSION

RT-PCR is a rapid and specific method for influenza A (H1N1) virus diagnosis. In addition, early administration of oseltamivir no later than 48 hours after the infection is highly recommended in either diabetic or DKA patients suspected of having H1N1.

Determinants of healthcare workers' willingness to recommend the seasonal influenza vaccine to diabetic patients: A cross-sectional survey in Ningbo, China

Background: Seasonal influenza vaccine uptake among diabetic patients is low in China. Recent studies showed healthcare workers'(HCWs') recommendation is an effective way to promote influenza vaccination. This study aimed to assess HCWs' willingness to recommend influenza vaccine to diabetic patients and identify the predictors of this willingness. Methods: During Dec 2016-Jan 2017, a self-administered questionnaire on perceptions, attitudes and practices related to influenza vaccination for diabetic patients was distributed to 1370 HCWs in 20 hospitals and 20 community health centers in Ningbo. Predictors of HCWs' willingness to recommend influenza vaccine were analyzed by logistic regressions. Results: Of 1340 HCWs who completed the survey, 58.13%(779/1340) participants reported willingness to recommend influenza vaccine to diabetic patients. Factors positively associated with the recommendation willingness included awareness of national influenza vaccination guideline(OR: 6.33; 95%CI: 4.66-8.60) and regional reimbursement policy(OR: 1.62; 95%CI: 1.19-2.20), training on influenza and diabetes (OR: 1.65; 95%CI: 1.21-2.23), influenza vaccination history(OR: 1.35; 95%CI: 1.01-1.79), beliefs in vaccine effects on reducing serious consequences(OR: 1.38; 95%CI: 1.01-1.91), reduction in hospitalization costs(OR: 1.43; 95%CI: 1.05-1.94) caused by influenza, and more than 10 years of practitioner experience(OR: 1.60; 95%CI: 1.04-2.46). Worries about side-effects of influenza vaccine were identified as the barriers of recommendation. Conclusion: The present study demonstrates that knowledge about national guideline and reimbursement policies, training programs, perceptions about effectiveness and safety of influenza vaccine increase HCWs' willingness to recommend the influenza vaccination to diabetic patients. These measures should be taken to ensure HCWs' role in the administration of influenza vaccination among diabetic patients.

Influenza Virus and Glycemic Variability in Diabetes: A Killer Combination?

Following the 2009 H1N1 influenza virus pandemic, numerous studies identified the striking link between diabetes mellitus and influenza disease severity. Typically, influenza virus is a self-limiting infection but in individuals who have a pre-existing chronic illness, such as diabetes mellitus, severe influenza can develop. Here, we discuss the latest clinical and experimental evidence for the role of diabetes in predisposing the host to severe influenza. We explore the possible mechanisms that underlie this synergy and highlight the, as yet, unexplored role that blood glucose oscillations may play in disease development. Diabetes is one of the world’s fastest growing chronic diseases and influenza virus represents a constant and pervasive threat to human health. It is therefore imperative that we understand how diabetes increases influenza severity in order to mitigate the burden of future influenza epidemics and pandemics.

[Database linkage for surveillance of the influenza A(H1N1)pdm09 pandemic in Brazil, 2009-2010]

Based on database linkage, the objective of this study was to describe the epidemiological profile of notified cases and deaths from the new viral subtype of influenza during the influenza pandemic. Secondary data were used from the SINAN (Information System for Notifiable Diseases) and SIM (Mortality Information System) for the years 2009 and 2010. Linkage identified 5,973 deaths of cases notified as pandemic influenza. Of these, 2,170 (36.33%) had been classified in the SINAN as confirmed pandemic influenza, 215 (3.6%) as due to other infectious agents, and 3,340 (55.92%) as ruled out. After linkage, some cases in the SINAN database that were closed as death from influenza (n = 658) or death from other causes (n = 847) could not be located in the SIM database. Database linkage can improve the surveillance system and monitoring of morbidity and mortality. We recommend strengthening influenza surveillance in Brazil using linkage of Ministry of Health databases.

Pulmonary function in patients with pandemic H1N1

Abstract Introduction: The influenza A (H1N1) was responsible for the 2009 pandemic, especially with severe pulmonary complications. Objective: To describe characteristics of patients in a university hospital in Curitiba - PR with laboratory diagnosis of influenza A (H1N1) and its post hospital discharge in the 2009 lung function pandemic. Methodology: A retrospective observational study. It was used as a data source the institution Epidemiology Service (SEPIH) and spirometry tests of patients who were admitted in 2009, 18 years without lung disease associated and non-pregnant. Descriptive statistics were used and applied Fisher's exact test for relationship between comorbidity and spirometry tests. Results: There were 84 confirmed cases, of these 11 were eligible for the study with a mean age of 44.27 years (± 9.63) and 63.63% males. 54.54% of the 11 patients had comorbidities associated with systemic arterial hypertension (54.54%), diabetes (18.18%) and late postoperative period of kidney transplantation (18.18%) were the most frequent. Most patients (81.81%) had BMI ≥ 25kg / m². The Spirometry test was performed approximately 40.09 (± 15.27) days after discharge, of these, 5 had restrictive pattern and all had abnormal chest radiograph results. There was no statistically significant difference between the results of Spirometry and comorbidities (p=0.24). Conclusions: The group evaluated in this research did not show a direct relationship between Spirometry and comorbidities, but changes in Spirometry in some patients after hospital discharge stood out, suggesting changes in lung function due to influenza A (H1N1).

High Body Mass Index as a Risk Factor for Hospitalization Due to Influenza: A Case-Control Study

INTRODUCTION

Obesity has emerged as a significant independent predictor of severity in pandemic influenzaA (H1N1)pdm09. The aim of this study was to investigate the association between body mass index (BMI) and the risk of hospitalization due to influenza.

METHODS

Hospitalized patients (n=755) with laboratory-confirmed influenza were individually matched by age, admission/visit date, and province with an outpatient (n=783) with laboratory-confirmed influenza and an outpatient control (n=950). We compared the BMI using conditional logistic regression adjusted for potential confounding factors (aOR). The population attributable fraction (PAF) was calculated.

RESULTS

A higher BMI was associated with an increased risk of hospitalization compared to both outpatient cases (aOR=1.11; 95%CI: 1.07-1.16) and outpatient controls (aOR=1.04; 95%CI: 1.01-1.07). Compared with normal weight, obesity type I, obesity type II and obesity type III was associated with a greater likelihood of hospitalization compared with outpatient cases (aOR=1.85, 95%CI: 1.05-3.26; aOR=5.24, 95%CI: 1.94-14.15 and aOR=44.38, 95%CI: 4.47-440.5). Compared with normal weight, obesity type II and obesity type III was associated with a greater likelihood of hospitalization compared with outpatient controls (aOR=4.37, 95%CI: 1.79-10.69 and aOR=4.95, 95%CI: 1.45-16.87). In persons without influenza vaccination, all categories of BMI≥30kg/m(2) were associated with a greater likelihood of hospitalization compared with normal weight in both outpatient cases and outpatient controls. The PAF of hospitalization by influenza due to BMI ranged from 21.9% to 8.5%; in the case of unvaccinated against influenza between 20.5% to 16.9%.

CONCLUSION

A high BMI is associated with an increased risk of hospitalization due to influenza. High percentage of hospital admissions are attributable to their BMI, especially in non vaccinated.

Clinical aspects of influenza A(H1N1)pdm09 cases reported during the pandemic in Brazil, 2009-2010

OBJECTIVE

To describe the clinical aspects of cases of influenza A(H1N1)pdm09 in Brazil.

METHODS

A descriptive study of cases reported in Sistema de Informação de Agravos de Notificação (SINAN), 2009-2010.

RESULTS

As the final classification, we obtained 53,797 (56.79%) reported cases confirmed as a new influenza virus subtype, and 40,926 (43.21%) cases discarded. Fever was the most common sign, recorded in 99.74% of the confirmed and 98.92% of the discarded cases. Among the confirmed cases, the presence of comorbidities was reported in 32.53%, and in 38.29% of the discarded cases. The case fatality rate was 4.04%; 3,267 pregnant women were confirmed positive for influenza A new viral subtype and 2,730 of them were cured. The case fatality rate of pregnant women was 6.88%.

CONCLUSION

The findings suggested concern of the health system with pregnant women, and patients with comorbidities and quality of care may have favored a lower mortality. We recommend that, when caring for patients with severe respiratory symptoms, with comorbidities, or pregnant women, health professionals should consider the need for hospital care, as these factors make up a worse prognosis of infection by the pandemic influenza virus.

Impact of HIV infection and smoking on lung immunity and related disorders

HIV-infected persons not only have higher rates of smoking than the general population, but are also unusually vulnerable to the associated adverse health effects, both infective and noninfective in origin. Indeed, in the setting of well-organised care and availability of highly active antiretroviral therapy, HIV-infected smokers lose more life-years to smoking than to HIV infection per se, presenting a major challenge to healthcare providers. Not surprisingly, the respiratory system is particularly susceptible to the damaging interactive chronic inflammatory and immunosuppressive effects of HIV and smoking, intensifying the risk of the development of opportunistic infections, as well as lung cancer and obstructive lung disorders. The impact of smoking on the immunopathogenesis and frequencies of these respiratory conditions in the setting of HIV infection, as well as on the efficacy of antiretroviral therapy, represent the primary focus of this review.

Effect of broccoli sprouts on nasal response to live attenuated influenza virus in smokers: a randomized, double-blind study

BACKGROUND

Smokers have increased susceptibility and altered innate host defense responses to influenza virus infection. Broccoli sprouts are a source of the Nrf2 activating agentsulforaphane, and short term ingestion of broccoli sprout homogenates (BSH) has been shown to reduce nasal inflammatory responses to oxidant pollutants.

OBJECTIVES

Assess the effects of BSH on nasal cytokines, virus replication, and Nrf2-dependent enzyme expression in smokers and nonsmokers.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial comparing the effects of BSH on serially sampled nasal lavage fluid (NLF) cytokines, viral sequence quantity, and Nrf2-dependent enzyme expression in NLF cells and biopsied epithelium. Healthy young adult smokers and nonsmokers ingested BSH or placebo (alfalfa sprout homogenate) for 4 days, designated Days -1, 0, 1, 2. On Day 0 they received standard vaccine dose of live attenuated influenza virus (LAIV) intranasally. Nasal lavage fluids and nasal biopsies were collected serially to assess response to LAIV.

RESULTS

In area under curve analyses, post-LAIV IL-6 responses (P = 0.03) and influenza sequences (P = 0.01) were significantly reduced in NLF from BSH-treated smokers, while

NAD(P)H

quinoneoxidoreductasein NLF cells was significantly increased. In nonsmokers, a similar trend for reduction in virus quantity with BSH did not reach statistical significance.

CONCLUSIONS

In smokers, short term ingestion of broccoli sprout homogenates appears to significantly reduce some virus-induced markers of inflammation, as well as reducing virus quantity. Nutritional antioxidant interventions have promise as a safe, low-cost strategy for reducing influenza risk among smokers and other at risk populations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01269723.

Influenza A (H1N1) pneumonia: HRCT findings

OBJECTIVE:

To describe aspects found on HRCT scans of the chest in patients infected with the influenza A (H1N1) virus.

METHODS:

We retrospectively analyzed the HRCT scans of 71 patients (38 females and 33 males) with H1N1 infection, confirmed through laboratory tests, between July and September of 2009. The HRCT scans were interpreted by two thoracic radiologists independently, and in case of disagreement, the decisions were made by consensus.

RESULTS:

The most common HRCT findings were ground-glass opacities (85%), consolidation (64%), or a combination of ground-glass opacities and consolidation (58%). Other findings were airspace nodules (25%), bronchial wall thickening (25%), interlobular septal thickening (21%), crazy-paving pattern (15%), perilobular pattern (3%), and air trapping (3%). The findings were frequently bilateral (89%), with a random distribution (68%). Pleural effusion, when observed, was typically minimal. No lymphadenopathy was identified.

CONCLUSIONS:

The most common findings were ground-glass opacities and consolidations, or a combination of both. Involvement was commonly bilateral with no axial or craniocaudal predominance in the distribution. Although the major tomographic findings in H1N1 infection are nonspecific, it is important to recognize such findings in order to include infection with the H1N1 virus in the differential diagnosis of respiratory symptoms.

Characteristics of Hospitalized Patients with Severe and Non-Severe Pandemic Influenza A (H1N1) in Saurashtra Region, India (Two Waves Analysis)

Background:

In India, the first case of 2009 pandemic influenza A (H1N1) virus infection was reported in May 2009 and the same in Saurashtra region in August 2009. We describe the epidemiology and factors associated with severe and non-severe cases of 2009 influenza A (H1N1) infection reported in the Saurashtra region.

Materials and Methods:

From September 2009 to January 2011, we reported 511 patients who were infected with 2009 influenza A (H1N1) virus and admitted in different hospitals of Rajkot city. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) testing was used to confirm infection. Factors associated with severe cases were determined by comparing with non-severe cases.

Results:

Out of 511 patients, 140 had severe disease (requiring intensive care or died) and 371 non-severe diseases (admitted in wards and survived). Median age of 30 years; median time of 5 days from onset of illness to diagnosis, and 4 days median time was reported for hospital stay among severe disease patients. More than half (60.7%) were females. Out of the patients with severe disease, 52.1% patients residing in urban area (OR = 1.68, CI = 1.13-2.49). Significant association was reported among severe disease patients for delayed referral from general practitioner/physician after initial treatment. All patients received antiviral drug, however, only 27.1% received within 2 days of illness. Presence of coexisting condition (pregnancy (OR = 0.19, CI = 0.08-0.48) was strongly associated with severe disease.

Conclusion:

Delayed referral from general practitioner/physician, duration of antiviral treatment, presence of coexisting condition (i.e., pregnancy) were responsible for intensive care or mortality among severe influenza A (H1N1) illness.

Cigarette smoking and mechanisms of susceptibility to infections of the respiratory tract and other organ systems

The predisposition of cigarette smokers for development of oral and respiratory infections caused by microbial pathogens is well recognised, with those infected with the human immunodeficiency virus (HIV) at particularly high risk. Smoking cigarettes has a suppressive effect on the protective functions of airway epithelium, alveolar macrophages, dendritic cells, natural killer (NK) cells and adaptive immune mechanisms, in the setting of chronic systemic activation of neutrophils. Cigarette smoke also has a direct effect on microbial pathogens to promote the likelihood of infective disease, specifically promotion of microbial virulence and antibiotic resistance. In addition to interactions between smoking and HIV infection, a number of specific infections/clinical syndromes have been associated epidemiologically with cigarette smoking, including those of the upper and lower respiratory tract, gastrointestinal tract, central nervous and other organ systems. Smoking cessation benefits patients in many ways, including reduction of the risk of infectious disease.