Multidisciplinary decision-making regarding chemotherapy for lung cancer patients-An age-based comparison.

Optimising decision-making in elderly patients is becoming increasingly urgent. We analysed treatment decisions and course of therapy for patients with lung cancer in different age categories: <65, 65-75, and 75 years and older. About 349 patients with lung cancer (median age 67.8 years), discussed at the multidisciplinary team meeting in the Diakonessenhuis Utrecht, the Netherlands, were reviewed. Multidisciplinary decision-making and subsequent clinical course were extracted from medical files. We found that 39% of eligible patients older than 75 years of age started treatment with chemotherapy compared to 80% of the younger patients (<65 and 65-75). When patients did receive chemotherapy, primary and secondary treatment adaptations were effectuated in 58%: for patients aged <65 in 49%, for patients aged 65-75 and >75 years in 66%. For 44% of all patients treated with chemotherapy, unplanned hospital admissions were required: in 42% for the patients <65, in 52% for those aged 65-75 and in 27% for >75 years. The decision-making process and course of treatment for lung cancer vary per age category. In particular, patients between 65 and 75 years of age might be more frail than initially thought. Age and frailty are important characteristics that need more attention.

Chemotherapy and healthcare utilisation near the end of life in patients with cancer.

The quality of medical care delivered to patients with cancer near the end of life is a significant issue. Previous studies have defined several areas suggestive of aggressive cancer treatment as potentially representing poor quality care. The primary objective of current analysis was to examine chemotherapy and healthcare utilisation in the last 3 months of life among patients with cancer that received palliative chemotherapy. Patients were selected from the hospital administration database of the Diakonessenhuis Utrecht, the Netherlands. Data were extracted from the medical files. A total of 604 patients were included for analysis (median age: 64 years). For 300 patients (50%) chemotherapy was given in the last 3 months (CT+). For 76% (n = 229) of CT+ patients unplanned hospital admissions were made in these last 3 months, compared to 44% (n = 133) of CT- patients (p < .001). Visits to the emergency room in last 3 months were made by 67% (n = 202) of CT+ patients compared to 43% (n = 132) of CT- patients (p < .001). Healthcare consumption was significantly higher in patients who received chemotherapy in the last 3 months of life. Being able to inform our patients about these aspects of treatment can help to optimise both the quality of life and the quality of dying in patients with cancer.

Diagnosing eosinophilic asthma using a multivariate prediction model based on blood granulocyte responsiveness.

BACKGROUND: The identification of inflammatory asthma phenotypes, using sputum analysis, has proven its value in diagnosis and disease monitoring. However due to technical limitations of sputum analysis, there is a strong need for fast and noninvasive diagnostics. This study included the activation state of eosinophils and neutrophils in peripheral blood to phenotype and monitor asthma. OBJECTIVES: To (i) construct a multivariable model using the activation state of blood granulocytes, (ii) compare its diagnostic value with sputum eosinophilia as gold standard and (iii) validate the model in an independent patient cohort. METHODS: Clinical parameters, activation of blood granulocytes and sputum characteristics were assessed in 115 adult patients with asthma (training cohort/Utrecht) and 34 patients (validation cohort/Oxford). RESULTS: The combination of blood eosinophil count, fractional exhaled nitric oxide, Asthma Control Questionnaire, medication use, nasal polyposis, aspirin sensitivity and neutrophil/eosinophil responsiveness upon stimulation with formyl-methionyl-leucyl phenylalanine was found to identify sputum eosinophilia with 90.5% sensitivity and 91.5% specificity in the training cohort and with 77% sensitivity and 71% specificity in the validation cohort (relatively high percentage on oral corticosteroids [OCS]). CONCLUSIONS: The proposed prediction model identifies eosinophilic asthma without the need for sputum induction. The model forms a noninvasive and externally validated test to assess eosinophilic asthma in patients not on OCS.

CT screening for pulmonary pathology in common variable immunodeficiency disorders and the correlation with clinical and immunological parameters.

BACKGROUND: Pulmonary disease is common in patients with common variable immunodeficiency disorders (CVID) and involves infections, chronic airway disease and interstitial lung disease. Chronic pulmonary disease is associated with excess morbidity and early mortality and therefore early detection and monitoring of progression is essential. METHODS AND PURPOSE: Thin slice CT scan and pulmonary function were used to determine the prevalence and spectrum of chronic (pre-clinical) pulmonary disease in adult CVID patients regardless of symptoms. CT Scans were scored for airway abnormalities (AD) and interstitial lung disease (ILD). Other CVID related complications and B and T lymphocyte subsets were analyzed to identify patients at risk for pulmonary disease. RESULTS: Significant pulmonary abnormalities were detected in 24 of the 47 patients (51%) consisting of AD in 30% and ILD in 34% of cases. In only 7 (29%) of these 24 patients pulmonary function test proved abnormal. The presence of AD was correlated to (recurrent) lower respiratory tract infections despite IgG therapy. The presence of ILD was correlated to autoimmune disease and a reduction in the numbers of CD4 + T cells, naïve CD4 + T cells, naïve CD8 + T cells and memory B cells and lower IgG through levels over time. CONCLUSION: Preclinical signs of AD and ILD are common in CVID patients despite Ig therapy and do not correlate to pulmonary function testing. Patients at risk for ILD might be identified by the presence of autoimmunity or a deranged T cell pattern. Larger studies are needed to confirm these findings and to determine thresholds for the T lymphocyte subsets.

Diabetes before and after lung transplantation in patients with cystic fibrosis and other lung diseases.

AIMS: The aims of the study are to investigate the prevalence of diabetes in patients with cystic fibrosis compared with patients without cystic fibrosis, and its impact on the outcome after lung transplantation. METHODS: Data were reviewed from 77 lung transplantation recipients in our centre between 2001 and 2010; 43 patients had cystic fibrosis and 34 patients had other lung diseases (no cystic fibrosis). To define diabetes, we used the American Diabetes Association definition. RESULTS: Before lung transplantation, diabetes was diagnosed in 63% of patients with cystic fibrosis and 6% of patients without cystic fibrosis (P<0.001). In both groups, approximately 60% of the patients at risk developed new-onset diabetes after transplantation. The mortality in patients with cystic fibrosis was higher in patients with diabetes diagnosed before lung transplantation compared with those without (44 vs. 6%, P=0.04). Diabetes remained an independent factor in multivariate analyses. CONCLUSIONS: Diabetes diagnosed before lung transplantation has a negative effect on survival after lung transplantation in patients with cystic fibrosis. Pre-existing diabetes is common in patients with cystic fibrosis, in contrast to patients without cystic fibrosis. Development of new-onset diabetes after transplantation is similar in both groups.

The relationship between lung function impairment and quantitative computed tomography in chronic obstructive pulmonary disease.

OBJECTIVES: To determine the relationship between lung function impairment and quantitative computed tomography (CT) measurements of air trapping and emphysema in a population of current and former heavy smokers with and without airflow limitation. METHODS: In 248 subjects (50 normal smokers; 50 mild obstruction; 50 moderate obstruction; 50 severe obstruction; 48 very severe obstruction) CT emphysema and CT air trapping were quantified on paired inspiratory and end-expiratory CT examinations using several available quantification methods. CT measurements were related to lung function (FEV(1), FEV(1)/FVC, RV/TLC, Kco) by univariate and multivariate linear regression analysis. RESULTS: Quantitative CT measurements of emphysema and air trapping were strongly correlated to airflow limitation (univariate r-squared up to 0.72, p < 0.001). In multivariate analysis, the combination of CT emphysema and CT air trapping explained 68-83% of the variability in airflow limitation in subjects covering the total range of airflow limitation (p < 0.001). CONCLUSIONS: The combination of quantitative CT air trapping and emphysema measurements is strongly associated with lung function impairment in current and former heavy smokers with a wide range of airflow limitation.

Quantitative computed tomography in COPD: possibilities and limitations.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease that is characterized by chronic airflow limitation. Unraveling of this heterogeneity is challenging but important, because it might enable more accurate diagnosis and treatment. Because spirometry cannot distinguish between the different contributing pathways of airflow limitation, and visual scoring is time-consuming and prone to observer variability, other techniques are sought to start this phenotyping process. Quantitative computed tomography (CT) is a promising technique, because current CT technology is able to quantify emphysema, air trapping, and large airway wall dimensions. This review focuses on CT quantification techniques of COPD disease components and their current status and role in phenotyping COPD.

Steroids induce a disequilibrium of secreted interleukin-1 receptor antagonist and interleukin-1ß synthesis by human neutrophils.

Chronic obstructive pulmonary disease (COPD) is characterised by neutrophilic inflammation in the airways and these neutrophils contribute to the production of inflammatory mediators. Dampening the production of proinflammatory mediators might be an important strategy to treat COPD and glucocorticosteroids are known to do so via inhibition of nuclear factor-κB. However, this pathway is important for the control of pro- and anti-inflammatory genes. We studied the effects of dexamethasone on production and secretion of pro-inflammatory interleukin (IL)-1ß and anti-inflammatory secreted IL-1 receptor antagonist (sIL-1Ra) by human neutrophils activated with tumor necrosis factor (TNF)-α. In vitro, TNF-α-stimulated neutrophils produced significant amounts of IL-1ß and sIL-1Ra; this production was inhibited by dexamethasone. However, synthesis and secretion of sIL-1Ra was inhibited at lower concentrations dexamethasone compared to IL-1ß, which changed the IL-1ß:sIL-1Ra ratio significantly. This altered ratio resulted in a more pro-inflammatory condition, as visualised by increased intercellular adhesion molecule-1 expression on human endothelial cells. In vivo, moderate-to-severe COPD patients using inhaled glucocorticosteroids have decreased plasma sIL-Ra levels compared with mild-to-moderate patients not on glucocorticosteroid treatment. In conclusion, dexamethasone induces a pro-inflammatory shift in the IL-1ß:sIL-1Ra cytokine balance in neutrophils in vitro, which might contribute to a lack of endogenous anti-inflammatory signals to dampen inflammation in vivo.

Association of the transfer coefficient of the lung for carbon monoxide with emphysema progression in male smokers.

A decreased transfer coefficient of the lung for carbon monoxide (K(CO)) is associated with emphysema. We evaluated whether in heavy smokers, baseline K(CO) was associated with the progression of computed tomography (CT)-detected emphysema, and the progression of airflow limitation. Heavy smokers, mean ± sd 41.3 ± 18.7 pack-yrs, participating in a lung cancer screening trial underwent diffusion testing and CT scanning of the lungs. CT scanning was repeated after median (25th-75th percentile) 2.8 (2.7-3.0) yrs and emphysema was assessed by lung densitometry using the 15th percentile. The association between K(CO) at baseline with progression of emphysema and lung function decline was assessed by multiple linear regression, correcting for baseline CT-quantified emphysema severity and forced expiratory volume in 1 s (FEV1/forced vital capacity (FVC), age, height, body mass index, pack-yrs and smoking status (current or former smoker). 522 participants aged 60.1 ± 5.4 yrs were included. Mean ± sd 15th percentile was -938 ± 19, absolute FEV1/FVC was 71.6 ± 9% and K(CO) was 1.23 ± 0.25, which is 81.8 ± 16.5% of predicted. By interpolation, a one sd (0.25) lower K(CO) value at baseline predicted a 1.6 HU lower 15th percentile and a 0.78% lower FEV1/FVC after follow-up (p < 0.001). A lower baseline K(CO) value is independently associated with a more rapid progression of emphysema and airflow limitation in heavy smokers.

The impact of using different symptom-based exacerbation algorithms in patients with COPD.

Not all exacerbations are captured by reliance on healthcare contacts. Symptom-based exacerbation definitions have shown to provide more adequate measures of exacerbation rates, severity and duration. However, no consensus has been reached on what is the most useful method and algorithm to identify these events. This article provides an overview of the existing symptom-based definitions and tests the hypothesis that differences in exacerbation characteristics depend on the algorithms used. We systematically reviewed symptom-based methods and algorithms used in the literature, and quantified the impact of the four most referenced algorithms on exacerbation-related outcome using an existing chronic obstructive pulmonary disease (COPD) cohort (n = 137). We identified 51 studies meeting our criteria using 14 widely varying symptom algorithms to define onset, severity and recovery. The most (71%) frequently referenced algorithm (modified Anthonisen) identified an incidence rate of 1.7 episodes·patient-yr⁻¹ (95% CI 1.4-2.1), while for requiring only one major or two major symptoms this was 1.9 episodes·patient-yr⁻¹ (95% CI 1.6-2.3) and 1.5 episodes·patient-yr⁻¹ (95% CI 0.6-1.0), respectively. Studies were generally lacking methods to enhance validity and accuracy of symptom recording. This review revealed large inconsistencies in definitions, methods and accuracy to define symptom-based COPD exacerbations. We demonstrated that minor changes in symptom criteria substantially affect incidence rates, clustering type and classification of exacerbations.

Pneumoconiosis and emphysema in construction workers: results of HRCT and lung function findings.

OBJECTIVES: To evaluate the prevalence of HRCT findings in construction workers previously surveyed by chest radiographs classified according to ILO guidelines. To examine the association between HRCT findings and exposure to quartz containing dust, and lung function. METHODS: The study comprised a questionnaire, dynamic and static lung function measurements, single-breath CO diffusion capacity, chest radiographs and HRCT in 79 individuals. Certified 'B' readers coded radiographs according to the ILO classification. HRCT scans were read according to an international classification system. A qualitative exposure index for cumulative respiratory quartz on a 10-point scale was used. RESULTS: Agreement between HRCT readers was good (κ>0.60), except for irregular opacities (κ=0.23). In ILO category 0/0, 8% HRCT round, 22% irregular and/or linear opacities and 41% HRCT emphysema was found. HRCT round opacities was associated with high cumulative quartz exposure (OR 7.1; 95% CI 1.3 to 37.8). Emphysema was associated with smoking (OR 10.1; 95% CI 1.2 to 84.2) and showed a reduction in T(L,CO,sb). HRCT round opacities was not associated with lung function. Current smoking was negatively associated with FEV1/FVC ratio and positively with RV/TLC ratio, and showed a reduction in T(L,CO,sb) (13.4%), adjusted for different HRCT findings. CONCLUSIONS: Low grade silicosis cannot be excluded in workers with normal chest radiographs (ILO 0/0). In relatively highly exposed construction workers, a sevenfold increased risk of simple (nodular) silicosis was found. Emphysema on HRCT was associated with current or former smokers, but not with exposure, and contributed to reduced diffusion capacity. Airflow limitation was mainly determined by current smoking and was not associated with simple (nodular) silicosis.

Prolonged protection of the new inhaled corticosteroid fluticasone furoate against AMP hyperresponsiveness in patients with asthma.

INTRODUCTION: Single-dose inhaled corticosteroids (ICS) induce direct anti-inflammatory effects in asthma thereby improving airway hyperresponsiveness (AHR). A novel enhanced-affinity ICS, fluticasone furoate (FF), demonstrated a prolonged duration of action in vitro. The aim of this study was to evaluate the efficacy and duration of action of a single dose of FF by studying protection against AHR to adenosine 5'-monophosphate (AMP) and effects on exhaled nitric oxide (eNO). METHODS: A randomized, double-blind, placebo-controlled, 6-way crossover study (FFA10026) was performed in 24 patients with allergic asthma (mean age 32.8 years, FEV(1) ≥ 70% predicted and PC(20) AMP ≤ 50 mg/ml). Each subject received a single dose of FF 1000 µg, fluticasone proprionate (FP) 1000 µg, or placebo at 2 (FF only), 14 or 26 h prior to AMP challenge and eNO measurement. RESULTS: FF significantly improved PC(20) AMP compared to placebo, the difference in doubling concentrations being 2.18 (95% confidence interval: 1.13-3.23), 1.54 (0.48-2.59), and 1.30 (0.26-2.34) at 2, 14 and 26 h. FP improved PC(20) AMP significantly at 14 h compared to placebo, but not at the 26-hour time point, the difference in doubling concentrations being 1.72 (0.70-2.75) and 0.33 (-0.69-1.34). There was no significant effect on eNO after either FF or FP at all time points. FF was well tolerated and there were no serious adverse events. CONCLUSION: The new inhaled corticosteroid FF, but not FP, demonstrates prolonged protection up to 26 h against AHR to AMP in asthma patients.

Effectiveness of pulmonary rehabilitation at high-altitude compared to sea-level in adults with severe refractory asthma.

BACKGROUND: Beneficial effects of pulmonary rehabilitation at high-altitude (HAPR) in patients with severe refractory asthma have been reported earlier, but evidence for the effectiveness is limited. AIM: To investigate the effectiveness of high-altitude pulmonary rehabilitation to comparable treatment at sea-level (LAPR) on patient outcome parameters. METHODS: Adults with severe refractory asthma living in The Netherlands were included. Treatment consisted of a 12-week personalized multidisciplinary rehabilitation program either at high-altitude (Davos Switzerland) (n = 93) or in a tertiary lung center at sea-level in The Netherlands (n = 45). At baseline, after treatment, and during 12 months follow-up asthma related quality of life (AQLQ), asthma control (ACQ), pulmonary function and OCS-dose were assessed. Patients could not be randomized resulting in different asthma populations. Groups were compared using linear regression analysis (ANCOVA) adjusted for baseline values, in addition to age, atopy, smoking history, BMI and gender. RESULTS: After treatment, and at 12 months follow-up, improved AQLQ(0.92,p < 0.001 and 0.82,p = 0.001, respectively), ACQ(-0.87,p < 0.001 and -0.69,p = 0.008, respectively) and lower maintenance OCS dose (Unadjusted linear regression analysis-5.29 mg, p = 0.003 and Crude Odds Ratio-1.67, p = 0.003, respectively) were observed in the HAPR-group compared to the LAPR group. Patients receiving HAPR also had less asthma exacerbations (≥1 exacerbation: 20% vs 60%,p < 0.001) and showed improvement in lung function (%predFEV1 3.4%,p = 0.014) compared to the LAPR group, but at 12 months no differences between groups were observed. CONCLUSION: HAPR resulted in a larger improvement in patient outcome parameters compared to LAPR, on the long run the improvement in patient reported symptoms and lower maintenance OCS-dose persists. Underlying factors that explain this observed effect need to be investigated.

Different respiratory phenotypes are associated with isocyanate exposure in spray painters.

Associations have been observed between exposure to isocyanates, consisting mainly of oligomers, and respiratory symptoms and isocyanate specific sensitisation in spray painters. The aim of the present study was to assess associations between isocyanate exposure and more objective respiratory effect measures such as bronchial hyperresponsiveness (BHR), baseline spirometry and exhaled nitric oxide (eNO) in a subset of spray painters. Methacholine challenge and eNO measurements were performed in 229 workers. Questionnaires and blood samples were obtained. Specific immunoglobulin (Ig)E and IgG to hexamethylene di-isocyanate were assessed in serum using various assays. Personal exposure was estimated by combining personal task-based inhalatory exposure measurements and time-activity information. Workers with higher isocyanate exposure were more often hyperresponsive (prevalence ratio comparing the 75th versus 25th percentile of exposure 1.8). In addition, significant exposure-related decreased forced expiratory volume in one second (FEV(1)), FEV(1)/forced vital capacity ratio and flow-volume parameters independent of BHR were found. BHR was more prevalent among sensitised workers. This was statistically significant for only IgG-ImmunoCAP (Phadia, Uppsala, Sweden) positive workers. eNO was not associated with exposure although slightly elevated eNO levels in specific IgG positive subjects were found. The current study provides evidence that exposure to isocyanate oligomers is related to asthma with bronchial hyperresponsiveness as a hallmark, but also shows independent chronic obstructive respiratory effects resulting from isocyanate exposure.

Cytokine-specific transcriptional regulation through an IL-5Ralpha interacting protein.

Cytokine receptors consist of multiple subunits, which are often shared between different receptors, resulting in the functional redundancy sometimes observed between cytokines. The interleukin 5 (IL-5) receptor consists of an IL-5-specific alpha-subunit (IL-5Ralpha) and a signal-transducing beta-subunit (betac) shared with the IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors. In this study, we sought to find a role for the cytoplasmic domain of IL-5Ralpha. We show that syntenin, a protein containing PSD-95/Discs large/zO-1 (PDZ) domains, associates with the cytoplasmic tail of the IL-5Ralpha. Syntenin was found to directly associate with the transcription factor Sox4. Association of syntenin with IL-5Ralpha was required for IL-5-mediated activation of Sox4. These studies identify a mechanism of transcriptional activation by cytokine-specific receptor subunits.

Effect of an inhaled adenosine A2A agonist on the allergen-induced late asthmatic response.

BACKGROUND: Adenosine receptor activation is suggested to play a role in asthmatic airway inflammation. Inhibition of adenosine receptors may have an effect on the late asthmatic response (LAR) after allergen inhalation and this mechanism could offer a potential new treatment in asthma. METHODS: We evaluated the effect of an inhaled adenosine-(2A) (A(2A))-receptor agonist (GW328267X), 25 microg, in 15 nonsmoking atopic asthmatics who underwent an inhaled allergen challenge following twice daily treatment for 1 week in a double-blind, placebo- and fluticasone propionate (250 microg) controlled study. RESULTS: In contrast to fluticasone, treatment with the A(2A)-receptor agonist neither significantly protect against the allergen-induced early and late asthmatic reaction, nor the accompanying inflammatory response as measured by sputum total cell counts, number of EG2+ cells, and the concentration of interleukin-8 and eosinophil cationic protein. CONCLUSION: The inhaled A(2A)-receptor agonist, GW328267X, 25 microg does not affect the allergen-induced LAR or the associated inflammatory response in asthma.

Allergen inhalation decreases adenosine receptor expression in sputum and blood of asthma patients.

BACKGROUND: Adenosine is a signalling nucleoside that has been proposed to contribute to the pathogenesis of asthma. Adenosine is produced in inflammatory environments and acts via adenosine receptors (A(1)R, A(2A)R, A(2B)R, and A(3)R) expressed by a wide variety of cells, resulting in pro- and anti-inflammatory effects. OBJECTIVE: To compare AR expression in asthma patients and healthy subjects, and to assess the effect of allergen challenge on AR expression of inflammatory cells and on cytokines in peripheral blood and sputum in asthma. METHODS: Asthma patients underwent an allergen challenge, and blood and induced sputum samples were taken before and 24 h after allergen challenge to study inflammatory cells numbers, AR expression and cytokine production. Blood and sputum were investigated at one time point in healthy subjects. AR expression was measured by flow cytometry (blood) or on cytospins using immunocytochemistry (sputum). Cytokines (luminex, ELISA) and adenosine (HPLC) were measured in sputum supernatant. RESULTS: The percentage of A(2B)R expressing neutrophils in sputum was lower in asthma patients than in healthy subjects (P = 0.016). Allergen challenge decreased A(1)R and A(2A)R expression on neutrophils and A(1)R expression on T cells in peripheral blood (all P < 0.05). Allergen challenge increased IL-8 levels and eosinophil numbers (P < 0.05), whereas it decreased thymic stromal lymphopoietin levels and the percentage of A(1)R expressing macrophages in induced sputum (P < 0.05). CONCLUSIONS: Allergen challenge has a down-regulatory effect on AR expression in asthma, suggesting a contribution of adenosine-related effector mechanisms in the pathophysiology.

Symptoms of influenza virus infection in hospitalized patients.

BACKGROUND: During influenza outbreaks, fever and cough are the most accurate symptoms in predicting influenza virus infection in the community. OBJECTIVE: To determine the usefulness of fever, cough, and other symptoms for diagnosing influenza virus infection in hospitalized patients. DESIGN: Prospective cohort study. SETTING: Three wards (pulmonology, internal medicine and infectious diseases, and geriatrics) of a tertiary care hospital in the Netherlands. PATIENTS: All patients staying in the wards during peak national influenza activity in the 2005-2006 and 2006-2007 influenza seasons. METHODS: During peak influenza activity, the presence of fever, cough, and/or other symptoms possibly associated with influenza was monitored for all patients, and nose and throat swab samples were taken twice weekly for virologic analysis. RESULTS: Of 264 patients, 23 (9%) tested positive for influenza virus. The positive predictive value of fever and cough for the diagnosis of influenza virus infection was 23% (95% confidence interval, 0%-62%), and the sensitivity was 35% (95% confidence interval, 11%-58%). The combination of symptoms with the highest positive predictive value (40%) was that of cough, chills, and obstructed nose or coryza. The combination of cough and chills or fever had the highest sensitivity (60%). None of the combinations of symptoms had both a positive predictive value and a sensitivity higher than 40%. CONCLUSIONS: Both the sensitivity and the positive predictive value of fever, cough, and/or other symptoms for the diagnosis of influenza virus infection in hospitalized patients are low. The use of these common symptoms for treatment decisions and infection control management will probably be insufficient to contain a nosocomial outbreak, because many influenza cases will remain unidentified.