Cigarette smoking as a risk factor for influenza-associated mortality: evidence from an elderly cohort

Factors associated with repeated influenza vaccine uptake among aged care staff in an Australian sample from 2017 to 2019

BACKGROUND/AIM

Influenza vaccination is strongly recommended every year for aged care staff to protect themselves and minimise risk of transmission to residents. This study aimed to determine the factors associated with repeated annual influenza vaccine uptake among Australian aged care staff from 2017 to 2019.

METHODS

Demographic, medical and vaccination data collected from the staff, who participated in an observational study from nine aged care facilities under a single provider in Sydney Australia, were analysed retrospectively. Based on the pattern of repeated influenza vaccination from 2017 to 2019, three groups were identified: (1) unvaccinated all three years; (2) vaccinated occasionally(once or twice) over three years; and (3)vaccinated all threeyears. Multinomial logistic regression analysis was performed to better understand the factors associated with the pattern of repeated influenza vaccination.

RESULTS

From a total of 138 staff, between 2017 and 2019, 28.9 % (n = 40) never had a vaccination, while 44.2 % (n = 61) had vaccination occasionally and 26.8 % (n = 37) had vaccination all three years. In the multinomial logistic regression model, those who were<40 years old (OR = 0.57, 95 % CI: 0.19-0.90, p < 0.05) and those who were current smokers (OR = 0.20; 95 % CI: 0.03-0.76, p < 0.05) were less likely to have repeated vaccination for all three years compared to the unvaccinated group. Those who were<40 years old (OR = 0.61; 95 % CI: 0.22-0.68, p < 0.05) and those who were born overseas (OR = 0.50; 95 % CI:0.27-0.69, p < 0.05) were more likely to be vaccinated occasionally compared to the unvaccinated group.

CONCLUSION

The significant predictors of repeated vaccine uptake across the three-year study period among aged care staff were age, smoking status and country of birth (Other vs Australia). Targeted interventions towards the younger age group (<40 years old), smokers and those who were born overseas could improve repeated influenza vaccination uptake in the aged care workforce.

Trends in Influenza Vaccination Rates in Participants With Airflow Limitation: The Korea National Health and Nutrition Examination Survey 2007-2018

Background

Influenza vaccination is strongly recommended for people with chronic lung diseases, including chronic obstructive pulmonary disease, to reduce risk of exacerbation. We assess the influenza vaccination rate and its related factors in participants with airflow limitation (AFL) using nationally representative data in Korea.

Methods

We conducted a cross-sectional study from the Korea National Health and Nutrition Examination Survey from 2007 to 2018. Individuals ≥ 40 years who underwent spirometry and had identifiable information on influenza vaccination status were included.

Results

Overall influenza vaccination coverage was 61.2% in participants with AFL and 41.8% in participants without AFL. Age had a significant impact on the yearly vaccination rate in participants with AFL. Over the 10 years of study period, while the yearly vaccination rate steadily increased from 58.3 to 61.9% in elderly participants (≥65 years) with AFL (p for trend = 0.117), the yearly vaccination rate decreased from 41.5% to 30.8% in younger participants (<65 years) (p for trend = 0.038). In multivariable analyses, younger age [adjusted odds ratio (OR) for unvaccinated = 0.88, 95% confidence interval (CI) = 0.87-0.90], male (adjusted OR = 1.64; 95% CI = 1.23-2.19), and current smokers (adjusted OR = 1.42, 95% CI = 1.01-2.00) were associated with increased odds of being unvaccinated.

Conclusions

The vaccination rate in participants with AFL affected by age. Younger age, male sex, and current smoking were associated with unvaccinated status. More attention and targeted interventions are required to improve the influenza vaccination rate in those with AFL.

Influenza Vaccination Status and Its Affecting Factors among Stroke Survivors: Findings from the Korea National Health and Nutrition Examination Survey

Few studies have examined the influenza vaccination rates among stroke survivors despite the importance of vaccines in preventing influenza- and stroke-related complications. Thus, we investigated the vaccination rates and the associated factors among stroke survivors using the representative Korea National Health and Nutrition Examination Survey 2014–2018. We measured and compared the vaccination rates of 591 stroke survivors and 17,997 non-stroke survivors. Multivariate logistic regression analyses of all stroke survivors and age subgroups (<65 and ≥65 years) were performed to identify the factors influencing vaccination. The overall vaccination rate was significantly higher in the stroke survivors (64.8%) than in the non-stroke survivors (41.1%), but it was low compared to global standards. Among stroke survivors aged <65 years, the rate was low (37.5%), but it improved in those aged ≥65 years (85.6%). Age ≥ 65 years, the eligible age for the national free vaccination program was the most prominent predictor of vaccination for all stroke survivors, while smoking was a negative predictor. No significant factors were found in the subgroup analyses according to age (<65 and ≥65 years). Therefore, implementing strategic public health policies, such as expanding the free vaccination program to stroke survivors aged <65 years, may improve vaccine coverage.

Respiratory-tract infections among geriatrics: prevalence and factors associated with the treatment outcomes

Background:

Geriatric individuals are more susceptible to different infections, especially respiratory-tract infections (RTIs) due to their compromised immune system. Hence, the objectives of the present study were to evaluate the prevalence, medication regimen complexity and factors associated with the treatment outcomes of different RTIs among geriatrics.

Methods:

A retrospective cross-sectional study (5 years) was conducted at the respiratory department, Hospital Pulau Pinang. Patients aged ⩾65 years with confirmed diagnosis of RTI were included in the study.

Results:

A total of 474 patients were included, and the most prevalent RTIs were community-acquired pneumonia (65.6%) followed by chronic obstructive pulmonary disease (20.7%), bronchitis (8.2%) and hospital-acquired pneumonia (5.5%). Amoxicillin/clavulanate (69.8%), ampicillin/sulbactam (9.1%) and cefuroxime (6.5%) are the most common antibiotics prescribed to treat RTIs among geriatrics. Smoking, alcohol consumption, polypharmacy and presence of other co-morbidities are statistically significant factors associated with treatment outcomes of RTIs among geriatrics.

Conclusion:

Prevalence of community-acquired pneumonia (65.6%) among older patients aged 65 years and older higher than other RTIs. Smoking, alcohol use, presence of polypharmacy and other co-morbidities are important factors associated with the treatment outcomes of RTIs.

The reviews of this paper are available via the supplemental material section.

Risk Factors for Pneumonia and Death in Adult Patients With Seasonal Influenza and Establishment of Prediction Scores: A Population-Based Study

Background

Seasonal influenza remains a global health problem; however, there are limited data on the specific relative risks for pneumonia and death among outpatients considered to be at high risk for influenza complications. This population-based study aimed to develop prediction models for determining the risk of influenza-related pneumonia and death.

Methods

We included patients diagnosed with laboratory-confirmed influenza between 2016 and 2017 (main cohort, n = 25 659), those diagnosed between 2015 and 2016 (validation cohort 1, n = 16 727), and those diagnosed between 2017 and 2018 (validation cohort 2, n = 34 219). Prediction scores were developed based on the incidence and independent predictors of pneumonia and death identified using multivariate analyses, and patients were categorized into low-, medium-, and high-risk groups based on total scores.

Results

In the main cohort, age, gender, and certain comorbidities (dementia, congestive heart failure, diabetes, and others) were independent predictors of pneumonia and death. The 28-day pneumonia incidence was 0.5%, 4.1%, and 10.8% in the low-, medium-, and high-risk groups, respectively (c-index, 0.75); the 28-day mortality was 0.05%, 0.7%, and 3.3% in the low-, medium-, and high-risk groups, respectively (c-index, 0.85). In validation cohort 1, c-indices for the models for pneumonia and death were 0.75 and 0.87, respectively. In validation cohort 2, c-indices for the models were 0.74 and 0.87, respectively.

Conclusions

We successfully developed and validated simple-to-use risk prediction models, which would promptly provide useful information for treatment decisions in primary care settings.

Influenza and Pneumococcal Vaccination in Non-Infected Cardiometabolic Patients from the Americas during the COVID-19 Pandemic. A Sub-Analysis of the CorCOVID-LATAM Study

BACKGROUND

Influenza vaccination (IV) and Pneumococcus vaccination (PV) are recommended for patients with cardiometabolic diseases. This study aimed to evaluate the immunization rate of ambulatory cardiometabolic patients during the COVID-19 pandemic in the Americas.

METHODS

Electronic surveys were collected from 13 Spanish speaking countries between 15 June and 15 July 2020.

RESULTS

4216 patients were analyzed. Mean age 60 (±15) years and 49% females. Global IV rate was 46.5% and PV 24.6%. Vaccinated patients were older (IV = 63 vs. 58 years; PV = 68 vs. 59, p < 0.01) but without gender difference. Vaccination rates were greater in higher-risk groups (65+, diabetics, heart failure), but not in coronary artery disease patients. In the Southern cone, the rate of IV and PV was approximately double that in the tropical regions of the Americas. In a multivariate model, geographic zone (IV = OR 2.02, PV = OR 2.42, p < 0.001), age (IV = OR 1.023, PV = OR 1.035, p < 0.001), and incomes (IV = OR 1.28, PV = OR 1.58, p < 0.001) were predictors for vaccination.

CONCLUSIONS

During the COVID-19 pandemic, ambulatory patients with cardiometabolic diseases from the Americas with no evidence of COVID-19 infection had lower-than-expected rates of IV and PV. Geographic, social, and cultural differences were found, and they should be explored in depth.

COVID-19 Disease Course in Former Smokers, Smokers and COPD Patients

The severe respiratory and systemic disease named coronavirus disease-2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, the COVID-19 pandemic presents a huge social and health challenge worldwide. Many different risk factors are associated with disease severity, such as systemic arterial hypertension, diabetes mellitus, obesity, older age, and other co-infections. Other respiratory diseases such as chronic obstructive pulmonary disease (COPD) and smoking are common comorbidities worldwide. Previous investigations have identified among COVID-19 patients smokers and COPD patients, but recent investigations have questioned the higher risk among these populations. Nevertheless, previous reports failed to isolate smokers and COPD patients without other comorbidities. We performed a longitudinal evaluation of the disease course of smokers, former smokers, and COPD patients with COVID-19 without other comorbidities, from hospitalization to hospital discharge. Although no difference between groups was observed during hospital admission, smokers and COPD patients presented an increase in COVID-19-associated inflammatory markers during the disease course in comparison to non-smokers and former smokers. Our results demonstrated that smoking and COPD are risk factors for severe COVID-19 with possible implications for the ongoing pandemic.

Cigarette Smoke Affects Dendritic Cell Populations, Epithelial Barrier Function, and the Immune Response to Viral Infection With H1N1

Smokers with apparently “healthy” lungs suffer from more severe and frequent viral respiratory infections, but the mechanisms underlying this observation are still unclear. Epithelial cells and dendritic cells (DC) form the first line of defense against inhaled noxes such as smoke or viruses. We therefore aimed to obtain insight into how cigarette smoke affects DCs and epithelial cells and how this influences the response to viral infection. Female C57BL/6J mice were exposed to cigarette smoke (CS) for 1 h daily for 24 days and then challenged i.n. with the viral mimic and Toll-like receptor 3 (TLR3) ligand poly (I:C) after the last exposure. DC subpopulations were analyzed 24 h later in whole lung homogenates by flow cytometry. Calu-3 cells or human precision-cut lung slices (PCLS) cultured at air-liquid interface were exposed to CS or air and subsequently inoculated with influenza H1N1. At 48 h post infection cytokines were analyzed by multiplex technology. Cytotoxic effects were measured by release of lactate dehydrogenase (LDH) and confocal imaging. In Calu-3 cells the trans-epithelial electrical resistance (TEER) was assessed. Smoke exposure of mice increased numbers of inflammatory and plasmacytoid DCs in lung tissue. Additional poly (I:C) challenge further increased the population of inflammatory DCs and conventional DCs, especially CD11b⁺ cDCs. Smoke exposure led to a loss of the barrier function in Calu-3 cells, which was further exaggerated by additional influenza H1N1 infection. Influenza H1N1-induced secretion of antiviral cytokines (IFN-α2a, IFN-λ, interferon-γ-induced protein 10 [IP-10]), pro-inflammatory cytokine IL-6, as well as T cell-associated cytokines (e.g., I-TAC) were completely suppressed in both Calu-3 cells and human PCLS after smoke exposure. In summary, cigarette smoke exposure increased the number of inflammatory DCs in the lung and disrupted epithelial barrier functions, both of which was further enhanced by viral stimulation. Additionally, the antiviral immune response to influenza H1N1 was strongly suppressed by smoke. These data suggest that smoke impairs protective innate mechanisms in the lung, which could be responsible for the increased susceptibility to viral infections in “healthy” smokers.

COVID-19 Susceptibility in chronic obstructive pulmonary disease

In barely nine months, the pandemic known as COVID-19 has spread over 200 countries, affecting more than 22 million people and causing over than 786 000 deaths. Elderly people and patients with previous comorbidities such as hypertension and diabetes are at an increased risk to suffer a poor prognosis after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although the same could be expected from patients with chronic obstructive pulmonary disease (COPD), current epidemiological data are conflicting. This could lead to a reduction of precautionary measures in these patients, in the context of a particularly complex global health crisis. Most COPD patients have a long history of smoking or exposure to other harmful particles or gases, capable of impairing pulmonary defences even years after the absence of exposure. Moreover, COPD is characterized by an ongoing immune dysfunction, which affects both pulmonary and systemic cellular and molecular inflammatory mediators. Consequently, increased susceptibility to viral respiratory infections have been reported in COPD, often worsened by bacterial co-infections and leading to serious clinical outcomes. The present paper is an up-to-date review that discusses the available research regarding the implications of coronavirus infection in COPD. Although validation in large studies is still needed, COPD likely increases SARS-CoV-2 susceptibility and increases COVID-19 severity. Hence, specific mechanisms to monitor and assess COPD patients should be addressed in the current pandemic.

Derivation and validation of a prediction rule for mortality of patients with respiratory virus-related pneumonia (RV-p score)

Background:

Respiratory viruses are important etiologies of community-acquired pneumonia. However, current knowledge on the prognosis of respiratory virus-related pneumonia (RV-p) is limited. Thus, here we aimed to establish a clinical predictive model for mortality of patients with RV-p.

Methods:

A total of 1431 laboratory-confirmed patients with RV-p, including 1169 and 262 patients from respective derivation and validation cohorts from five teaching hospitals in China were assessed between January 2010 and December 2019. A prediction rule was established on the basis of risk factors for 30-day mortality of patients with RV-p from the derivation cohort using a multivariate logistic regression model.

Results:

The 30-day mortality of patients with RV-p was 16.8% (241/1431). The RV-p score was composed of nine predictors (including respective points of mortality risk): (a) age ⩾65 years (1 point); (b) chronic obstructive pulmonary disease (1 point); (c) mental confusion (1 point); (d) blood urea nitrogen (1 point); (e) cardiovascular disease (2 points); (f) smoking history (2 points); (g) arterial pressure of oxygen/fraction of inspiration oxygen (P_aO₂/FiO₂) < 250 mmHg (2 points); (h) lymphocyte counts <0.8 × 10⁹/L (2 points); (i) arterial PH < 7.35 (3 points). A total of six points was used as the cut-off value for mortality risk stratification. Our model showed a sensitivity of 0.831 and a specificity of 0.783. The area under the receiver operating characteristic curve was more prominent for RV-p scoring [0.867, 95% confidence interval (CI)0.846–0.886] when compared with both pneumonia severity index risk (0.595, 95% CI 0.566–0.624, p < 0.001) and CURB-65 scoring (0.739, 95% CI 0.713–0.765, p < 0.001).

Conclusion:

RV-p scoring was able to provide a good predictive accuracy for 30-day mortality, which accounted for a more effective stratification of patients with RV-p into relevant risk categories and, consequently, help physicians to make more rational clinical decisions.

The reviews of this paper are available via the supplemental material section.

COVID-19 and Individual Genetic Susceptibility/Receptivity: Role of ACE1/ACE2 Genes, Immunity, Inflammation and Coagulation. Might the Double X-chromosome in Females Be Protective against SARS-CoV-2 Compared to the Single X-Chromosome in Males?

In December 2019, a novel severe acute respiratory syndrome (SARS) from a new coronavirus (SARS-CoV-2) was recognized in the city of Wuhan, China. Rapidly, it became an epidemic in China and has now spread throughout the world reaching pandemic proportions. High mortality rates characterize SARS-CoV-2 disease (COVID-19), which mainly affects the elderly, causing unrestrained cytokines-storm and subsequent pulmonary shutdown, also suspected micro thromboembolism events. At the present time, no specific and dedicated treatments, nor approved vaccines, are available, though very promising data come from the use of anti-inflammatory, anti-malaria, and anti-coagulant drugs. In addition, it seems that males are more susceptible to SARS-CoV-2 than females, with males 65% more likely to die from the infection than females. Data from the World Health Organization (WHO) and Chinese scientists show that of all cases about 1.7% of women who contract the virus will die compared with 2.8% of men, and data from Hong Kong hospitals state that 32% of male and 15% of female COVID-19 patients required intensive care or died. On the other hand, the long-term fallout of coronavirus may be worse for women than for men due to social and psychosocial reasons. Regardless of sex- or gender-biased data obtained from WHO and those gathered from sometimes controversial scientific journals, some central points should be considered. Firstly, SARS-CoV-2 has a strong interaction with the human ACE2 receptor, which plays an essential role in cell entry together with transmembrane serine protease 2 (TMPRSS2); it is interesting to note that the ACE2 gene lays on the X-chromosome, thus allowing females to be potentially heterozygous and differently assorted compared to men who are definitely hemizygous. Secondly, the higher ACE2 expression rate in females, though controversial, might ascribe them the worst prognosis, in contrast with worldwide epidemiological data. Finally, several genes involved in inflammation are located on the X-chromosome, which also contains high number of immune-related genes responsible for innate and adaptive immune responses to infection. Other genes, out from the RAS-pathway, might directly or indirectly impact on the ACE1/ACE2 balance by influencing its main actors (e.g., ABO locus, SRY, SOX3, ADAM17). Unexpectedly, the higher levels of ACE2 or ACE1/ACE2 rebalancing might improve the outcome of COVID-19 in both sexes by reducing inflammation, thrombosis, and death. Moreover, X-heterozygous females might also activate a mosaic advantage and show more pronounced sex-related differences resulting in a sex dimorphism, further favoring them in counteracting the progression of the SARS-CoV-2 infection.

FluA-p score: a novel prediction rule for mortality in influenza A-related pneumonia patients

BACKGROUND

The pneumonia severity index (PSI) and the CURB-65 (confusion, urea, respiratory rate, blood pressure, age ≥ 65 years) score have been shown to predict mortality in community-acquired pneumonia. Their ability to predict influenza-related pneumonia, however, is less well-established.

METHODS

A total of 693 laboratory-confirmed FluA-p patients diagnosed between Jan 2013 and Dec 2018 and recruited from five teaching hospitals in China were included in the study. The sample included 494 patients in the derivation cohort and 199 patients in the validation cohort. The prediction rule was established based on independent risk factors for 30-day mortality in FluA-p patients from the derivation cohort.

RESULTS

The 30-day mortality of FluA-p patients was 19.6% (136/693). The FluA-p score was based on a multivariate logistic regression model designed to predict mortality. Results indicated the following significant predictors (regression statistics and point contributions toward total score in parentheses): blood urea nitrogen > 7 mmol/L (OR 1.604, 95% CI 1.150-4.492, p = 0.040; 1 points), pO₂/F_iO₂ ≤ 250 mmHg (OR 2.649, 95% CI 1.103-5.142, p = 0.022; 2 points), cardiovascular disease (OR 3.967, 95% CI 1.269-7.322, p < 0.001; 3 points), arterial PH < 7.35 (OR 3.959, 95% CI 1.393-7.332, p < 0.001; 3 points), smoking history (OR 5.176, 95% CI 2.604-11.838, p = 0.001; 4 points), lymphocytes < 0.8 × 10⁹/L (OR 8.391, 95% CI 3.271-16.212, p < 0.001; 5 points), and early neurominidase inhibitor therapy (OR 0.567, 95% CI 0.202-0.833, p = 0.005; - 2 points). Seven points was used as the cut-off value for mortality risk stratification. The model showed a sensitivity of 0.941, a specificity of 0.762, and overall better predictive performance than the PSI risk class (AUROC = 0.908 vs 0.560, p < 0.001) and the CURB-65 score (AUROC = 0.908 vs 0.777, p < 0.001).

CONCLUSIONS

Our results showed that a FluA-p score was easy to derive and that it served as a reliable prediction rule for 30-day mortality in FluA-p patients. The score could also effectively stratify FluA-p patients into relevant risk categories and thereby help treatment providers to make more rational clinical decisions.

Cigarette smoking and the occurrence of influenza - Systematic review

OBJECTIVES

The association of current smoking with influenza infection is not widely recognised. The aim of this systematic review was to summarise published evidence and quantify the risk of influenza infection in tobacco smokers compared to non-smokers.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL, LILACS and Web of Science, from inception to 7 November 2017, to identify relevant randomised control trials, cohort and case-control studies. Study quality was assessed using the Newcastle-Ottawa Scale. We included studies defining influenza as a clinical syndrome and those using confirmatory microbiological tests. Pooled odds ratios (ORs) were estimated by using random effects model.

RESULTS

The mean quality score across the nine included studies (n = 40,685 participants) was 5.4 of 9 (SD 1.07). Current smokers were over 5 times more likely to develop laboratory-confirmed influenza than non-smokers (pooled OR 5.69 (95% CI 2.79-11.60), 3 studies). For studies reporting the occurrence of an influenza-like illness (ILI), current smokers were 34% more likely to develop ILI than non-smokers (pooled OR 1.34 (95% CI 1.13-1.59), 6 studies).

CONCLUSION

Current smokers have an increased risk of developing influenza compared to non-smokers. The association was strongest in studies examining cases with laboratory confirmed influenza.

Influenza B associated paediatric acute respiratory infection hospitalization in central vietnam

Background

Influenza B is one of the major etiologies for acute respiratory infections (ARI) among children worldwide; however, its clinical‐epidemiological information is limited. We aimed to investigate the hospitalization incidence and clinical‐epidemiological characteristics of influenza B‐associated paediatric ARIs in central Vietnam.

Methods

We collected clinical‐epidemiological information and nasopharyngeal swabs from ARI children hospitalized at Khanh Hoa General Hospital, Nha Trang, Vietnam from February 2007 through June 2013. Nasopharyngeal samples were screened for 13 respiratory viruses using Multiplex‐PCRs. Influenza B‐confirmed cases were genotyped by Haemagglutinin gene sequencing. We analyzed the clinical‐epidemiological characteristics of influenza B Lineages (Victoria/Yamagata) and WHO Groups.

Results

In the pre‐A/H1N1pdm09 period, influenza B‐associated ARI hospitalization incidence among children under five was low, ranging between 14.7 and 80.7 per 100 000 population. The incidence increased to between 51.4 and 330 in the post‐A/H1N1pdm09. Influenza B ARI cases were slightly older with milder symptoms. Both Victoria and Yamagata lineages were detected before the A/H1N1pdm09 outbreak; however, Victoria lineage became predominant in 2010‐2013 (84% Victoria vs 16% Yamagata). Victoria and Yamagata lineages did not differ in demographic and clinical characteristics. In Victoria lineage, Group1 ARI cases were clinically more severe compared to Group5, presenting a greater proportion of wheeze, tachypnea, and lower respiratory tract infection.

Conclusions

The current results highlight the increased incidence of influenza B‐related ARI hospitalization among children in central Vietnam in the post‐A/H1N1pdm09 era. Furthermore, the difference in clinical severity between Victoria lineage Group1 and 5 implies the importance of influenza B genetic variation on clinical presentation.

Protective role of γδ T cells in cigarette smoke and influenza infection

Airborne pathogens commonly trigger severe respiratory failure or death in smokers with lung disease. Cigarette smoking compromises the effectiveness of innate immunity against infections but the underlying mechanisms responsible for defective acquired immune responses in smokers remains less clear. We found that mice exposed to chronic cigarette smoke recovered poorly from primary Influenza A pneumonia with reduced type I and II interferons (IFNs) and viral-specific immunoglobulins, but recruited γδ T cells to the lungs that predominantly expressed interleukin 17A (IL-17A). Il-17a^-/- mice exposed to smoke and infected with Influenza A also recruited γδ T cells to the lungs, but in contrast to wild-type mice, expressed increased IFNs, made protective influenza-specific antibodies, and recovered from infection. Depletion of IL-17A with blocking antibodies significantly increased T-bet expression in γδ T cells and improved recovery from acute Influenza A infection in air, but not smoke-exposed mice. In contrast, when exposed to smoke, γδ T cell deficient mice failed to mount an effective immune response to Influenza A and showed increased mortality. Our findings demonstrate a protective role for γδ T cells in smokers and suggest that smoke-induced increase in IL-17A inhibits the transcriptional programs required for their optimal anti-viral responses. Cigarette smoke induces IL-17A expression in the lungs and inhibits γδ T-cell-mediated protective anti-viral immune responses.

Secondhand Smoke Induces Inflammation and Impairs Immunity to Respiratory Infections

Despite advocacy to reduce smoking-related diseases, >1 billion people worldwide continue to smoke. Smoking is immunosuppressive and an important etiological factor in the development of several human disorders including respiratory diseases like chronic obstructive pulmonary disease. However, there is a critical gap in the knowledge of the role of secondhand smoke (SHS) in inflammation and immunity. We therefore studied the influence of SHS on pulmonary inflammation and immune responses to respiratory infection by nontypeable Haemophilus influenzae (NTHI) recurrently found in chronic obstructive pulmonary disease patients. Chronic SHS-exposed mice were chronically infected with NTHI and pulmonary inflammation was evaluated by histology. Immune cell numbers and cytokines were measured by flow cytometry and ELISA, respectively. Chronic SHS exposure impaired NTHI P6 Ag-specific B and T cell responses following chronic NTHI infection as measured by ELISPOT assays, reduced the production of Abs in serum and bronchoalveolar lavage, and enhanced albumin leak into the bronchoalveolar lavage as determined by ELISA. Histopathological examination of lungs revealed lymphocytic accumulation surrounding airways and bronchovasculature following chronic SHS exposure and chronic infection. Chronic SHS exposure enhanced the levels of inflammatory cytokines IL-17A, IL-6, IL-1β, and TNF-α in the lungs, and impaired the generation of adaptive immunity following either chronic infection or P6 vaccination. Chronic SHS exposure diminished bacterial clearance from the lungs after acute NTHI challenge, whereas P6 vaccination improved clearance equivalent to the level seen in air-exposed, non-vaccinated mice. Our study provides unequivocal evidence that SHS exposure has long-term detrimental effects on the pulmonary inflammatory microenvironment and immunity to infection and vaccination.

Effects of cigarette smoke on pulmonary endothelial cells

Cigarette smoking is the leading cause of preventable disease and death in the United States. Cardiovascular comorbidities associated with both active and secondhand cigarette smoking indicate the vascular toxicity of smoke exposure. Growing evidence supports the injurious effect of cigarette smoke on pulmonary endothelial cells and the roles of endothelial cell injury in development of acute respiratory distress syndrome (ARDS), emphysema, and pulmonary hypertension. This review summarizes results from studies of humans, preclinical animal models, and cultured endothelial cells that document toxicities of cigarette smoke exposure on pulmonary endothelial cell functions, including barrier dysfunction, endothelial activation and inflammation, apoptosis, and vasoactive mediator production. The discussion is focused on effects of cigarette smoke-induced endothelial injury in the development of ARDS, emphysema, and vascular remodeling in chronic obstructive pulmonary disease.

Connective Tissue Growth Factor Promotes Pulmonary Epithelial Cell Senescence and Is Associated with COPD Severity

The purpose of this study was to determine whether expression of connective tissue growth factor (CTGF) protein in chronic obstructive pulmonary disease (COPD) is consistent in humans and animal models of COPD and to investigate the role of this protein in lung epithelial cells. CTGF in lung epithelial cells of ex-smokers with COPD was compared with ex-smokers without COPD by immunofluorescence. A total of twenty C57Bl/6 mice and sixteen non-human primates (NHPs) were exposed to cigarette smoke (CS) for 4 weeks. Ten mice of these CS-exposed mice and eight of the CS-exposed NHPs were infected with H3N2 influenza A virus (IAV), while the remaining ten mice and eight NHPs were mock-infected with vehicle as control. Both mRNA and protein expression of CTGF in lung epithelial cells of mice and NHPs were determined. The effects of CTGF overexpression on cell proliferation, p16 protein, and senescence-associated β-galactosidase (SA-β-gal) activity were examined in cultured human bronchial epithelial cells (HBECs). In humans, CTGF expression increased with increasing COPD severity. We found that protein expression of CTGF was upregulated in lung epithelial cells in both mice and NHPs exposed to CS and infected with IAV compared to those exposed to CS only. When overexpressed in HBECs, CTGF accelerated cellular senescence accompanied by p16 accumulation. Both CTGF and p16 protein expression in lung epithelia are positively associated with the severity of COPD in ex-smokers. These findings show that CTGF is consistently expressed in epithelial cells of COPD lungs. By accelerating lung epithelial senescence, CTGF may block regeneration relative to epithelial cell loss and lead to emphysema.

Age and Sex Differences in Rates of Influenza-Associated Hospitalizations in Hong Kong

Few studies have explored age and sex differences in the disease burden of influenza, although men and women probably differ in their susceptibility to influenza infections. In this study, quasi-Poisson regression models were applied to weekly age- and sex-specific hospitalization numbers of pneumonia and influenza cases in the Hong Kong SAR, People's Republic of China, from 2004 to 2010. Age and sex differences were assessed by age- and sex-specific rates of excess hospitalization for influenza A subtypes A(H1N1), A(H3N2), and A(H1N1)pdm09 and influenza B, respectively. We found that, in children younger than 18 years, boys had a higher excess hospitalization rate than girls, with the male-to-female ratio of excess rate (MFR) ranging from 1.1 to 2.4. MFRs of hospitalization associated with different types/subtypes were less than 1.0 for adults younger than 40 years except for A(H3N2) (MFR = 1.6), while all the MFRs were equal to or higher than 1.0 in adults aged 40 years or more except for A(H1N1)pdm09 in elderly persons aged 65 years or more (MFR = 0.9). No MFR was found to be statistically significant (P < 0.05) for hospitalizations associated with influenza type/subtype. There is some limited evidence on age and sex differences in hospitalization associated with influenza in the subtropical city of Hong Kong.

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.

Socioeconomic status and other related factors of seasonal influenza vaccination in the South Korean adult population based on a nationwide cross-sectional study

Purpose

We investigated the association between seasonal influenza vaccination in South Korea and socioeconomic status (SES) as well as other potential related factors.

Methods

The study was based on data obtained in the Korea National Health and Nutrition Examination Survey from 2010 to 2011. Education level and household income were used as indicators for SES. Univariate and multiple logistic regression analyses were used to evaluate SES and other demographic variables as related factors for influenza vaccination, the primary outcome.

Results

Higher household income was positively associated with higher vaccine uptake in the younger (19–49 years) group [adjusted odds ratio (aOR) 1.55, 95% confidence interval (CI) 1.08–2.23], whereas the low-income and low-education group had increased vaccination coverage than the middle-income and middle-education group in the older (≥ 50 years) group (aOR 1.36, 95% CI 1.09–1.69). Current smokers tend to be unvaccinated in all age groups. Among individuals aged ≥ 50, older age, mild to moderate alcohol consumption, regular exercise, and having co-morbidities were positively associated with vaccination, while those who self-reported their health status as good were less likely to be vaccinated.

Conclusions

The relationship between SES and seasonal influenza vaccination coverage differed between the age groups throughout the adult South Korean population. Public health policies need to address these inequalities.

Cohort Profile: Hong Kong Department of Health Elderly Health Service Cohort

The Department of Health Elderly Health Service Cohort in Hong Kong was set up to promote understanding of ageing in a global context, to exploit the role of Hong Kong as a sentinel for populations currently experiencing very rapid economic development, to provide a developed non-Western 'social laboratory' where empirically derived hypotheses can be tested and to leverage the different patterns of common chronic diseases between East and West to generate novel hypotheses about their determinants. The initial cohort enrolled from July 1998 to the end of December 2001 includes 66 820 people aged 65 years or older, forming about 9% of the population of this age. A comprehensive health assessment was made at enrollment and then repeated regularly on an ongoing basis. The health assessment included a comprehensive assessment of lifestyle, social circumstances, physical health and mental health, including an assessment of cognition and depressive symptoms. Health services use and deaths have been obtained by record linkage and confirmed, where necessary, by telephone interview. Currently, the data are not publicly available; we would welcome collaborations and research proposals.

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.

Viral etiology of influenza-like illnesses during the influenza season between December 2011 and April 2012

The aim of this study was to determine the frequency of respiratory viruses responsible for respiratory tract infections in Turkish children during the 2011–2012 influenza season. Nasal swabs were obtained from patients with symptoms suggestive of an influenza‐like illness between December 2011 and April 2012. Samples were analyzed with multiplex real‐time polymerase chain reaction (RT‐PCR) to help identify the causative viral pathogen. A total of 200 patients were enrolled in the study. A respiratory virus was detected successfully in 102 (51%) children; influenza A (H3N2) in 39.2%, influenza B in 23.5%, RSV in 15.6%, rhinovirus in 13.7%, bocavirus in 2.9%, coronavirus in 2.9%, and metapneumovirus in 0.9% of patients. Only one patient was co‐infected with bocavirus and influenza A virus. A statistically significant difference in the mean age of presentation was observed between the various viral pathogens (P < 0.001). Patients with RSV were significantly younger whereas children infected with the influenza viruses were significantly older. Comparison of symptoms revealed that fever and headache occurred more frequently with the influenza viruses than the other viruses combined (P < 0.001, <0.05). Durations of symptoms such as fever, cough, nasal congestion, and rhinorrhea were also significantly longer in the influenza group (P < 0.001, <0.005, <0.001, <0.005, respectively). Demographic analyses revealed that the school/daycare attendance was the only parameter associated with a significantly increased risk for influenza infection. With an overall viral pathogen detection rate of 51%, findings of the present study suggest other respiratory pathogens, whether viral or bacterial, may also lead to hospital visits due to influenza‐like illnesses in children. J. Med. Virol. 86:865–871, 2014. © 2013 Wiley Periodicals, Inc.

Obesity and influenza associated mortality: evidence from an elderly cohort in Hong Kong

OBJECTIVE

Obesity was not identified as a risk factor for influenza until the recent 2009 H1N1 pandemic. Based on a cohort of 66,820 subjects aged 65 years and over with the follow-up period from July 1998 to December 2010 in Hong Kong, we assessed the modifying effect of obesity on mortality risks specifically attributable to influenza infections (termed as "influenza associated mortality risks").

METHODS

A Cox proportional model with time dependent covariates was adopted to assess the hazard ratio of mortality in each obesity group when influenza activity increased 10% in the community.

RESULTS

Hazard ratio of influenza-associated all-cause mortality was 1.081 (95% confidence interval 1.013, 1.154), 1.047 (1.012, 1.084), 0.981 (0.936, 1.028), 1.018 (0.980, 1.058) and 1.062 (0.972, 1.162) in the underweight, normal, overweight, moderate obesity and severe obesity groups, respectively. A similar U shape pattern across the obesity groups was also observed in influenza associated mortality risks of respiratory diseases, pneumonia and influenza. This pattern was more evident among ever smokers, although the influenza effect estimates in each obesity group had overlapping confidence intervals.

CONCLUSION

There is some but limited evidence to suggest that underweight and obesity were associated with higher mortality risks of influenza in old population.

Relationship between community prevalence of obesity and associated behavioral factors and community rates of influenza-related hospitalizations in the United States

Please cite this paper as: Charland et al.(2012) Relationship between community prevalence of obesity and associated behavioral factors and community rates of influenza‐related hospitalizations in the United States. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12019.

Background  Findings from studies examining the association between obesity and acute respiratory infection are inconsistent. Few studies have assessed the relationship between obesity‐related behavioral factors, such as diet and exercise, and risk of acute respiratory infection.

Objective  To determine whether community prevalence of obesity, low fruit/vegetable consumption, and physical inactivity are associated with influenza‐related hospitalization rates.

Methods  Using data from 274 US counties, from 2002 to 2008, we regressed county influenza‐related hospitalization rates on county prevalence of obesity (BMI ≥ 30), low fruit/vegetable consumption (<5 servings/day), and physical inactivity (<30 minutes/month recreational exercise), while adjusting for community‐level confounders such as insurance coverage and the number of primary care physicians per 100 000 population.

Results  A 5% increase in obesity prevalence was associated with a 12% increase in influenza‐related hospitalization rates [adjusted rate ratio (ARR) 1·12, 95% confidence interval (CI) 1·07, 1·17]. Similarly, a 5% increase in the prevalence of low fruit/vegetable consumption and physical inactivity was associated with an increase of 12% (ARR 1·12, 95% CI 1·08, 1·17) and 11% (ARR 1·11, 95% CI 1·07, 1·16), respectively. When all three variables were included in the same model, a 5% increase in prevalence of obesity, low fruit/vegetable consumption, and physical inactivity was associated with 6%, 8%, and 7% increases in influenza‐related hospitalization rates, respectively.

Conclusions  Communities with a greater prevalence of obesity were more likely to have high influenza‐related hospitalization rates. Similarly, less physically active populations, with lower fruit/vegetable consumption, tended to have higher influenza‐related hospitalization rates, even after accounting for obesity.