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The majority of fatalities thus far in the COVID-19 pandemic have been attributed to pneumonia. As expected, the fatality rate reported in China is higher in people with chronic pulmonary disease (6.3%) and those who have cancer (5.6%). According to the American College of Cardiology Clinical Bulletin "COVID-19 Clinical Guidance for the CV Care Team", there is a significantly higher fatality rate in people who are elderly (8.0% 70-79 years; 14.8% ≥80 years), diabetic (7.3%), hypertensive (6.0%), or have known cardiovascular disease (CVD) (10.5%). We propose a biological reason for the higher mortality risk in these populations that is apparent. We further present a set of pathophysiological reasons for the heightened danger that could lead to therapies for enhanced management and prevention., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: The current study examined how the pattern of systemic inflammation in the decades leading up to late-life relates to depression symptoms in older adults., Methods: Within the Atherosclerosis Risk in Communities Study, we measured high-sensitivity C-reactive protein (CRP), a nonspecific marker of systemic inflammation, at three visits: 21 years and 14 years before, and concurrent with the assessment of depression symptoms, defined using the 11-item Center for Epidemiologic Studies Depression (CESD) scale. We categorized participants into one of four groups based on their 21-year longitudinal pattern of elevated (≥3 mg/L) versus low (<3 mg/L) CRP (stable low; unstable low; unstable elevated; stable elevated). Analyses excluded participants with suspected depression during midlife., Results: A total of 4,614 participants were included (age at CESD assessment: 75.5 [SD: 5.1]; 59% female; follow-up time: 20.7 years [SD: 1.0]). Compared to participants who maintained low CRP levels (stable low), participants who had elevated CRP at two of three visits (unstable elevated; ß = 0.09; 95% confidence interval [CI]: 0.02, 0.17) and participants who maintained elevated CRP at all three visits (stable elevated; ß = 0.13; 95% CI: 0.05, 0.21) had greater depression symptoms as older adults, after adjusting for confounders. After excluding participants with late-life cognitive impairment, only participants with stable elevated CRP demonstrated significantly greater late-life depression symptoms. In a secondary analysis, stable elevated CRP was associated with increased risk for clinically significant late-life depression symptoms., Conclusion: Chronic or repeated inflammation in the decades leading up to older adulthood is associated with late-life depression, even in the context of normal cognition., (Copyright © 2019 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.)

Background/objectives: Previous research suggests that everyday discrimination is associated with worse episodic memory and partially mediates Black-White disparities in memory aging. The biological mechanisms underlying the link between everyday discrimination and memory are unclear but may involve inflammatory processes. This study aimed to determine whether systemic inflammation, indexed by blood levels of C-reactive protein (CRP), mediates associations between everyday discrimination and episodic memory over 6 years., Design: A longitudinal mediation model quantified associations between baseline everyday discrimination, 4-year change in CRP, and 6-year change in episodic memory., Setting: The Health and Retirement Study (HRS)., Participants: 12,624 HRS participants aged 51 and older., Measurements: Everyday Discrimination Scale, high-sensitivity CRP assays of dried blood spots, composite scores of immediate and delayed recall of a word list., Results: Black participants reported greater everyday discrimination. Greater discrimination was associated with lower baseline memory and faster memory decline. Higher CRP at baseline partially mediated the negative association between discrimination and baseline memory, but CRP change did not mediate the association between discrimination and memory decline., Conclusion: This U.S.-representative longitudinal study provides evidence for deleterious effects of discrimination on subsequent episodic memory. The fact that elevated CRP only partially explained the concurrent association between discrimination and memory highlights the need for more comprehensive investigations of biological mechanisms underlying the link between social stress and age-related memory decline in order to better characterize potential intervention targets to reduce racial inequalities in memory aging., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Importance: The outcome of older patients with acute myeloid leukemia (AML) remains unsatisfactory. Recent studies have shown that HLA-mismatched microtransplant could improve outcomes in such patients., Objective: To evaluate outcomes in different age groups among older patients with newly diagnosed AML who receive HLA-mismatched microtransplant., Design, Setting, and Participants: This multicenter clinical study included 185 patients with de novo AML at 12 centers in China, the United States, and Spain in the Microtransplantation Interest Group. Patients were divided into the following 4 age groups: 60 to 64 years, 65 to 69 years, 70 to 74 years, and 75 to 85 years. The study period was May 1, 2006, to July 31, 2015., Exposures: Induction chemotherapy and postremission therapy with cytarabine hydrochloride with or without anthracycline, followed by highly HLA-mismatched related or fully mismatched unrelated donor cell infusion. No graft-vs-host disease prophylaxis was used., Main Outcomes and Measures: The primary end point of the study was to evaluate the complete remission rates, leukemia-free survival, and overall survival in different age groups. Additional end points of the study included hematopoietic recovery, graft-vs-host disease, relapse rate, nonrelapse mortality, and other treatment-related toxicities., Results: Among 185 patients, the median age was 67 years (range, 60-85 years), and 75 (40.5%) were female. The denominators in adjusted percentages in overall survival, leukemia-free survival, relapse, and nonrelapse mortality are not the sample proportions of observations. The overall complete remission rate was not significantly different among the 4 age groups (75.4% [52 of 69], 70.2% [33 of 47], 79.1% [34 of 43], and 73.1% [19 of 26). The 1-year overall survival rates were 87.7%, 85.8%, and 77.8% in the first 3 age groups, which were much higher than the rate in the fourth age group (51.7%) (P = .004, P = .008, and P = .04, respectively). The 2-year overall survival rates were 63.7% and 66.8% in the first 2 age groups, which were higher than the rates in the last 2 age groups (34.2% and 14.8%) (P = .02, P = .03, P < .001, and P < .001, respectively). The 1-year cumulative incidences of nonrelapse mortality were 10.2%, 0%, 3.4%, and 26.0% in the 4 age groups and 8.1% in all patients. The median times to neutrophil and platelet recovery were 12 days and 14 days after induction chemotherapy, respectively. Five patients had full or mixed donor engraftment, and 30.8% (8 of 26) of patients demonstrated donor microchimerism. Two patients (1.1%) developed severe acute graft-vs-host disease., Conclusions and Relevance: Microtransplant achieved a high complete remission rate in AML patients aged 60 to 85 years and higher 1-year overall survival in those aged 60 to 74 years.

Background: Frailty is associated with immune activation and inflammation in the elderly general population, but whether this is true in the younger HIV-infected (HIV+) population is not known., Methods: We analyzed 24 serologic biomarkers of monocyte, T-cell, or B-cell activation in HIV- (n = 207) and HIV+ (n = 714; 75% virologically suppressed) men who have sex with men in the Multicenter AIDS Cohort Study (MACS) and were classified as frail or nonfrail according to expression or nonexpression of the frailty phenotype at 2 consecutive study visits., Results: After correction for multiple comparisons and adjustment for age, race, study site, and education, frailty in HIV+ men was significantly (P < 0.002) associated with higher levels of sCD14, sIL2Rα, sTNF-R2, IL-6, and TNF-α; the association with higher levels of C-reactive protein (CRP) approached significance (P = 0.003). After further adjustment for body mass index (BMI), smoking, and comorbidities, only the association with C-reactive protein was significant at P < 0.002, with levels approximately 50% higher in frail compared with nonfrail men. These conclusions were not altered by restricting the analysis to HIV+ men who were virologically suppressed. Among HIV- men, none of these markers differed significantly by frailty., Conclusions: These data suggest that frailty in virologically suppressed HIV+ men was associated with immune activation beyond that due to treated HIV infection. The inflammatory markers associated with frailty were primarily products of activated monocytes/macrophages. Much, but not all, activation was accounted for by harmful behaviors and comorbidities. However, C-reactive protein, which is regulated by IL-6, was elevated in HIV+ frail men independent of these factors.

With the advances in antiretroviral therapy (ART), HIV infection has been transformed into a chronic medical condition that can be effectively managed like diabetes or hypertension. For HIV care providers, the focus of care for many patients has shifted from prevention of opportunistic infection and AIDS-related conditions to age-related cardiometabolic comorbidities, including cardiovascular disease, diabetes, obesity, and frailty. Numerous reports have highlighted that these diseases are occurring at an earlier age among HIV-infected persons. However, there is an ongoing debate regarding the role of HIV infection, ART, and other factors that may underlie the accelerated occurrence of these diseases. Herein, we review the epidemiology of the US HIV epidemic with regards to several metabolic comorbidities and address mechanisms that likely contribute to the current nature of HIV disease.

Vaccines play a key role in the prevention of illness in the elderly, are cost effective, and generally safe. Hepatitis C, cirrhosis, autoimmune hepatitis, and inflammatory bowel disease are more prevalent than ever among older adults. Along with an age-related decline in immune system function (immunosenescence), these diseases make elderly individuals more susceptible to infections and more likely to experience a poor outcome relative to their younger counterparts. Vaccinations also appear to be less effective in the elderly, warranting research into different vaccination strategies such as booster vaccines, higher doses of vaccine, and measurement of antibody titers to guide vaccination., (Copyright © 2014 Elsevier Inc. All rights reserved.)

HIV-infected patients are living longer as a result of potent antiretroviral therapy. Immuno-inflammatory phenomena implicated in the normal aging process, including immune senescence, depreciation of the adaptive immune system, and heightened systemic inflammation are also pathophysiologic sequelae of HIV infection, suggesting HIV infection can potentiate the biological mechanisms of aging. Aging HIV-infected patients manifest many comorbidities at earlier ages, and sometimes with more aggressive phenotypes compared to seronegative counterparts. In this review, we describe relevant biologic changes shared by normal aging and HIV infection and explore the growing spectrum of clinical manifestations associated with the accelerated aging phenotype in HIV-infected individuals.

Objective: Understand the links between race and C-reactive protein (CRP), with special attention to gender differences and the role of class and behavioral risk factors as mediators., Method: This study utilizes the National Social Life, Health, and Aging Project data, a nationally representative study of older Americans aged 57-85 to explore two research questions. First, what is the relative strength of socioeconomic versus behavioral risk factors in explaining race differences in CRP levels? Second, what role does gender play in understanding race differences? Does the relative role of socioeconomic and behavioral risk factors in explaining race differences vary when examining men and women separately?, Results: When examining men and women separately, socioeconomic and behavioral risk factor mediators vary in their importance. Indeed, racial differences in CRP among men aged 57-74 are little changed after adjusting for both socioeconomic and behavioral risk factors with levels 35% higher for black men as compared to white men. For women aged 57-74, however, behavioral risk factors explain 30% of the relationship between race and CRP., Discussion: The limited explanatory power of socioeconomic position and, particularly, behavioral risk factors, in elucidating the relationship between race and CRP among men, signals the need for research to examine additional mediators, including more direct measures of stress and discrimination.

Older individuals (≥50 years of age) are increasingly becoming a new at-risk group for HIV-1 infection and, together with those surviving longer due to the introduction of anti-retroviral therapy (ART), it is predicted that more than half of all HIV-1-infected individuals in the United States will be greater than 50 years of age in the year 2015. Older individuals diagnosed with HIV-1 are prone to faster disease progression and reduced T-cell reconstitution despite successful virologic control with anti-retroviral therapy (ART). There is also growing evidence that the T-cell compartment in HIV-1(+) adults displays an aged phenotype, and HIV-1-infected individuals are increasingly diagnosed with clinical conditions more commonly seen in older uninfected persons. As aging in the absence of HIV infection is associated with alterations in T-cell function and immunosenescence, the combined impact of both HIV-1 infection and aging may provide an explanation for poorer clinical outcomes observed in older HIV-1-infected individuals. Thus, the development of novel therapeutics to stimulate immune function and delay immunosenescence is critical and would be beneficial to both the elderly and HIV-1-infected individuals.

Allergies and asthma are diseases that affect individuals of all ages, and their prevalence is comparable in all age groups. As age demographics in the United States and other countries shift to greater proportions and numbers of patients in the "elderly" categories, it is becoming increasingly important for clinicians to become aware of the impact of aging on a variety of diseases. Allergy and asthma are recognized as inflammatory disorders, and there are data demonstrating that age-related changes in immune function can have a significant impact on these disorders., (© Thieme Medical Publishers.)

On 23 December 2009, the US FDA approved Fluzone&#x00AE; High Dose, a high-dose formulation of the trivalent inactivated influenza vaccine, for prevention of influenza in people 65 years of age and older. As it was approved via an accelerated process designed to allow expeditious availability of safe and effective products with promise to treat or prevent serious or life-threatening diseases, the manufacturer is required to conduct further studies to demonstrate effectiveness. Although these studies are underway, a recently completed randomized, controlled trial demonstrated that this vaccine, containing four-times more hemagglutinin than standard-dose inactivated influenza vaccines, can produce an enhanced immunologic response in subjects of 65 years of age and older, while maintaining a favorable safety profile. This article introduces the vaccine, presents currently available safety and immunogenicity data, discusses current recommendations for use, and proposes what we can expect in the coming years.

Objective: To review the effect of increasing age on the immune system and some of its clinical implications., Data Sources: MEDLINE and PubMed searches were performed cross-referencing the keywords immunosenescence, aging, and immunity. Articles were reviewed for additional citations., Study Selection: Articles were reviewed and selected based on relevance to subject matter., Results: The study of immunosenescence is complex and not completely understood. Aging affects both the innate and adaptive arms of the immune response. With increased age, there may be a decrease in phagocytosis, alteration of cellular migration, changes in cell populations and numbers, and a decreased ability to produce specific antibodies. Clinically, these changes potentially increase morbidity and mortality in elderly individuals through an increased rate of infections, malignancy, and autoimmunity., Conclusions: The process of aging is accompanied by diverse changes in immunity. Several therapeutic approaches are under investigation, including cytokine therapy, hormonal replacement, antioxidant supplementation, and caloric restriction, to attenuate or potentially reverse immunosenescence.

Aging is associated with declines in immune system function, or 'immunosenescence', leading to progressive deterioration in both innate and adaptive immunity. These changes contribute to the decreased response to vaccines seen in many older adults, and morbidity and mortality from infection. Infections (e.g., influenza, pneumonia and septicemia) appear among the top ten most-common causes of death in adults in the USA aged 55 years and older. As immunosenescence has gathered more attention in the scientific and healthcare communities, investigators have demonstrated more links between immunosenescent changes and morbidity and mortality related to infections and declining vaccine responses. This review summarizes the recent literature on age-dependent defects in adaptive and innate immunity, data linking these defects to poor vaccine response and morbidity and mortality, current recommendations for vaccinations and potential strategies to improve vaccine efficacy in older adults.

Abnormal cytokine production by T-helper 1 (Th1)/T-helper 2 (Th2) lymphocytes has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Few studies have examined Th1/Th2 cytokine status in pediatric IBD patients, and results have been inconsistent. We used flow cytometric detection of intracellular IFN-gamma/IL-4 cytokine production to investigate CD4+, Th1, and Th2 cells in the peripheral blood of children with untreated, newly diagnosed Crohn's disease (CD) (n = 23) and matched healthy controls (n = 49). Th1 cytokine levels were lower in CD patients compared with controls (p = 0.006) and strongly correlated with levels of albumin and hematocrit (r = 0.51, p = 0.007 and r = 0.35, p = 0.052, respectively). An age-dependent increase in Th1 cells was observed (p < 0.0005); however, no correlation was found between age, clinical end points, %CD4+, or Th2 cell numbers. In conclusion, the Th1 cytokine levels in blood are lower in early onset CD patients than in healthy children and are directly associated with disease-related clinical parameters. In future studies of pediatric IBD patients, it will be critical to consider the effect of age and disease progression on cytokine status in intestinal mucosa and peripheral blood.

In recent years, there has been increasing regulatory pressure to protect the health of children, with the basic tenet being that children differ significantly from adults in their biological or physiological responses to chemical exposures. In a regulatory context, this has been translated to mean a requirement for an additional 10-fold safety factor for environmental contaminants, specialized tests, or both. Much of the initial focus has been on the developing endocrine and nervous systems; but increasingly, the developing immune system has been identified as a potential target organ for chemically mediated toxicity. More recently, the question has been raised regarding whether the current state of science supports the creation of developmental immunotoxicology (DIT) test guidelines. What is needed is a risk-based evaluation of the biology associated with the proposed differential sensitivity between children and adults and the impact of that assessment on additional regulatory measures to protect children in risk assessment analyses. Additionally, an understanding of whether the developing immune system shows greater susceptibility, either qualitatively or quantitatively, to chemical perturbation is critical. To address the question "What's so special about the developing immune system?" a symposium was organized for the 2003 Society of Toxicology annual meeting that brought together risk assessors, clinicians, immunologists, and toxicologists.

The number of elderly individuals is rapidly growing. As a result, more emergency transports will involve the care of an elderly patient. Distinguishing the cause of symptoms can be difficult for healthcare professionals, including emergency personnel. Clinical symptoms of infection may be absent, or not as obvious as with a younger individual. The aging process of the immune system results in the inability to fight off many infections. Transport of patients with antibiotic-resistant organisms has caused many challenges for emergency care personnel surrounding infection control practices.

Research has been conducted on the relationship between postnatal mortality from meningococcal infections and age, using data from the US during the period 1950-1991. The logarithm of mortality caused by meningococcal infections fell linearly with the logarithm of age, during the interval of 1-30 years for men and women in the US. The slope of this straight line is equal to -1. The mortality from meningococcal infections is inversely proportional to the age in the US. The risk of death at age 2 is one half of the risk at age 1, at age 3 it is one third of the risk of death at age 1, etc. up to the age of 30 in the US. The same decline was observed for the risk of death from congenital anomalies and pneumonia.

Infection with HIV, the virus that causes AIDS, is now considered a chronic disease of years rather than an acute condition resulting in death. AIDS in older adults accounts for 11% of all AIDS cases. This article discusses current epidemiological trends and statistics; HIV risk factors related to aging; immunity and the aging process; diagnosis and treatment challenges; as well as gerontological nursing implications related to HIV prevention and counseling for adults age 50 and older. HIV infection is preventable. Nurses have a unique opportunity to develop theory-based intervention programs to reduce risk behaviors, while encouraging healthy behaviors in the older adult population.

Growing old is not what it used to be. Many self-care actions can enhance one's chance of growing old without illness or disease. This necessitates preparing for old age while one is young. Preparation for second adulthood can vastly improve physical and emotional health in old age. It is important that nurses and other health care professionals teach health promotion strategies to persons at all ages in order to assist individuals to live life to its fullest throughout their lifetime.

The historic development of immunology is associated with Eli Metchnikoff who introduced the term 'gerontology' in 1906. Metchnikoff also understood the impact of population aging on society as revealed in two remarkable books. The immune system is relevant to aging in so many ways immunesenescence, the potential role of immunological changes in the dementias, the interrelationship of immune resistance and bereavement, retirement and other life changes and transplantation biology and pathology. These are only a few examples of the interrelationships of immunology and aging. The economic and political implications of immunology and aging are rarely discussed. If we are not able to cure the disorders of longevity, we need to delay their onset and progression. Such an effort is enhanced by modern biology including recombinant DNA and Hybridoma technology. Many in society fear the growing numbers of older persons-can we afford old age? Will population aging lead to stagnation of society and will there be intergenerational conflicts? These gloomy notions are not entirely offset by enthusiasm for an extended high quality longevity. This presentation will discuss these various issues and offer positive solutions.

A large portion of our older adult patients remain unimmunised or inadequately immunised against tetanus. The US is unique in that clinical tetanus occurs mostly in persons aged over 60 years. Worldwide, it is a disease of neonates. Both pneumococcal diseases and influenza cause markedly greater morbidity and mortality among elderly people compared with younger people. The prevalence of these chronic diseases can be decreased by immunising susceptible persons against the relevant infections. Hepatitis B is also a worldwide problem, causing a large number of acute infections and costly sequelae, 95% of which is preventable by hepatitis B vaccine. Rabies is a very lethal disease preventable by use of rabies vaccine. The decreased function of the aging immune system results in far fewer older persons developing antibodies following immunisation than their younger counterparts.

Objective: Our purpose was to determine whether the presence of autoantibodies is associated with pregnancy history in healthy adults., Study Design: Antibodies against phospholipid, histone, and nucleotide antigens were determined in 102 male and 99 female subjects. The effects of age, sex, marital status, and pregnancy history on antibody positivity were assessed., Results: Women showed higher levels of autoantibodies, but differences were not statistically significant in this sample. Age was not associated with antibody positivity in men. In women age was associated with positivity for (1) immunoglobulin G antibodies (p = 0.009), (2) antihistone antibodies (p = 0.024), and (3) more than one antibody (p = 0.020). Immunoglobulin M antibodies were more common in unmarried than married females (p = 0.020). In contrast, the prevalence of immunoglobulin G antibodies was increased in married women, although differences did not reach statistical significance (p = 0.167). Gravidity and history of fetal loss were not associated with increased antibody positivity. In subjects in whom follow-up data were available, positive antibody titers were not associated with subsequent adverse pregnancy outcome., Conclusions: In this population autoantibodies are not associated with adverse pregnancy outcome. However, an increased prevalence of immunoglobulin M in unmarried women and immunoglobulin G in married women suggests that a switch from immunoglobulin M to immunoglobulin G autoantibodies is associated with marriage, as a result of either exposure to semen or trophoblast antigens.

As part of a comprehensive study of current and former US Air Force personnel, an extensive assessment of the immune system of 497 normal male subjects was conducted in 1987. Cell surface marker studies for CD2 (total T cells), CD4 (helper T cells), CD8 (suppressor T cells), CD25 (activated T cells), CD20 (total B cells), CD14 (monocytes), and HLA-DR positive cell populations were measured. The CD4/CD8 ratio was also calculated. Functional stimulation assays were also performed using phytohemagglutinin (PHA) and a culture of mixed lymphocytes. Assays of natural killer cells with and without interleukin-2 stimulation were done. In addition to the distribution and range of values for each assay, statistical analyses were performed to determine the effect of age, race, percentage body fat, tobacco use and alcohol consumption on each variable. Age and alcohol consumption had significant correlation with suppressed counts and functions on nearly all variables while tobacco use was associated with stimulation of both T-cell numbers and function. These findings highlight the importance of using age-specific ranges of normal values for these tests of immunity and the need to consider life-style factors in the interpretation of the laboratory assessment of immune status.

The independent association of individual allergen reactivity with respiratory disease was evaluated with use of the second National Health and Nutrition Examination Survey, a sample of the U.S. white civilian population, ages 6 to 24 years (n = 4295). Eight, 1:20 wt/vol, 50% glycerol, unstandardized extracts were administered by prick puncture. Allergen reactivity was reported as the percent with a mean erythema diameter 10.5 mm or greater at 20 minutes. Only the prevalence of asthma and allergic rhinitis increased with the increasing number of positive allergen skin tests. The independent association of individual allergen reactivity with respiratory disease was quantified with logistic models that included other allergen reactivity, age, sex, smoking, and region. Asthma was associated with reactivity to house dust (odds ratio, 2.9; 95% confidence interval [CI] 1.7 to 5) and Alternaria (odds ratio, 5.1; 95% CI: 2.9 to 8.9). Allergic rhinitis was associated with reactivity to ragweed (odds ratio, 2.3; 95% CI: 1.5 to 3.3); ryegrass (odds ratio, 2.8; 95% CI: 1.8 to 4.3); house dust (odds ratio, 2.5; 95% CI: 1.6 to 3.9); Alternaria (odds ratio, 2.3; 95% CI: 1.5 to 3.4). Asthma only (without allergic rhinitis) was associated with dust and Alternaria. Allergic rhinitis only (without asthma) was associated with ryegrass, ragweed, and house dust. When both asthma and allergic rhinitis were present, only house dust and Alternaria remained associated. These findings highlight the association of specific allergens with upper and lower respiratory diseases and the interactions among coexisting respiratory diseases.

The major risk factor for cancer is progressive age. Molecular advances in our understanding of carcinogenesis and the aging process are helping to clarify this relationship. The magnitude of cancer in the elderly warrants institution of an active prevention program by clinicians caring for this population.

Nosocomial pneumonia may account for a relatively small percent of all hospital-acquired infections, but it is associated with the highest mortality of all nosocomial infections. Risk factors include increasing age, thoracoabdominal surgery, presence of chronic lung disease, duration in hospital, immunosuppressive therapy, continuous ventilatory support, and means of payment. Among patients dying in the hospital, a nosocomial pneumonia was present in 40% and was causally related or contributed to death in 60% of nosocomially infected patients. Gram-negative bacilli, Staphylococcus aureus, and viruses are the most common etiologic agents. Changes in T lymphocytes with aging, alterations in the physiologic and anatomic defenses from trauma, disease, or aging and lack of appropriate infection control barriers predispose to development of pneumonia. Extra hospital charges of approximately $1,000 and four to five additional hospital days result. Analysis of pertinent epidemiologic data require understanding of clinical definition of pneumonia, laboratory methods used to analyze respiratory secretions, and methods of comparing added charges and length of stay.