Agreement between Internet-based self- and proxy-reported health care resource utilization and administrative health care claims.

OBJECTIVES: Although Internet-based surveys are becoming more common, little is known about agreement between administrative claims data and Internet-based survey self- and proxy-reported health care resource utilization (HCRU) data. This analysis evaluated the level of agreement between self- and proxy-reported HCRU data, as recorded through an Internet-based survey, and administrative claims-based HCRU data. METHODS: The Child and Household Influenza-Illness and Employee Function study collected self- and proxy-reported HCRU data monthly between November 2007 and May 2008. Data included the occurrence and number of visits to hospitals, emergency departments, urgent care centers, and outpatient offices for a respondent's and his or her household members' care. Administrative claims data from the MarketScan® Databases were assessed during the same time and evaluated relative to survey-based metrics. Only data for individuals with employer-sponsored health care coverage linkable to claims were included. The Kappa (κ) statistic was used to evaluate visit concordance, and the intraclass correlation coefficient was used to describe frequency consistency. RESULTS: Agreement for presence of a health care visit and the number of visits were similar for self- and proxy-reported HCRU data. There was moderate to substantial agreement related to health care visit occurrence between survey-based and claims-based HCRU data for inpatient, emergency department, and office visits (κ: 0.47-0.77). There was less agreement on health care visit frequencies, with intraclass correlation coefficient values ranging from 0.14 to 0.71. CONCLUSIONS: This study's agreement values suggest that Internet-based surveys are an effective method to collect self- and proxy-reported HCRU data. These results should increase confidence in the use of the Internet for evaluating disease burden.

Cost-effectiveness and socio-economic aspects of childhood influenza vaccination.

Children have high rates of healthcare utilization due to influenza. In addition, children also transmit influenza to others in their households and the community. The costs of influenza in children include the direct medical care costs from increased outpatient visits and hospitalizations, and also indirect costs due to productivity losses especially for their parents and due to transmission of the virus to others. A variety of studies using different methods and assumptions have assessed the cost-effectiveness of influenza vaccination of children, and many find that vaccination is either cost saving or cost effective.

Telephone survey assessment of household patterns of influenza vaccination, Twin Cities seven county metro area, 2008-2009.

Major national surveys do not collect the influenza vaccination status of all household members, thus limiting current understanding of household influenza vaccination patterns. In an early 2009 telephone survey of 800 households in the metropolitan Minneapolis-St Paul area, household respondents reported the age, gender, and 2008-2009 seasonal influenza vaccination status of all household members. After poststratification to adjust for nonresponse, the full household influenza vaccination rate for multiperson households is 35.2%, partial household influenza vaccination rate is 39.9% and the rate of complete household nonvaccination is 24.9%. Full household influenza vaccination is more common in households with an elderly resident, intermediate in households with a child under 5 years of age, and less common in the remaining households. No household members are vaccinated in approximately 10% of multiperson households with either an elderly adult or young child; the corresponding rate in other households is 32.8%. An estimated 51.4% of households with children over 1 year of age have all children vaccinated against influenza; 43.5% of households with children had no children vaccinated against influenza. Households with younger children are more likely to have all children vaccinated and less likely to have no children vaccinated. We believe this is the first study to describe the prevalence of household influenza vaccination patterns. Continued efforts to monitor and increase household vaccination may be a valuable strategy to protect individuals and communities from influenza.

Employees' willingness to pay to prevent influenza.

OBJECTIVES: To quantify employees' preferences, as measured by willingness to pay, to prevent influenza in themselves and in their child and adult household members and to examine factors associated with willingness to pay. STUDY DESIGN: Prospective observational cohort study of a convenience sample of employees from 3 large US employers. Participants had at least 1 child (< or = 17 years) living in their household for at least 4 days per week. METHODS: Each month from November 2007 to April 2008, employees completed Web-based surveys regarding acute respiratory illness in their household. In the final survey, employees were presented with descriptions of influenza and questions regarding their willingness to pay to prevent influenza. Factors associated with willingness to pay were examined using multivariate ordinary least squares regression analysis of the log of willingness to pay. RESULTS: Among 2006 employees, 31.3% were female, the mean age was 41.7 years, 85.3% were of white race/ethnicity, and the mean household size was 4.0. Employees' median (mean) willingness to pay to prevent influenza was $25 ($72) for themselves, $25 ($82) for their adult household members, and $50 ($142) (P <.01) for children. However, influenza vaccination rates were approximately equal for children (27.5%), employees (31.5%), and other adult household members (24.5%). This finding may be explained by barriers such as cost, dislike of vaccinations, and disagreement with national influenza vaccination recommendations, which were significantly associated with lower willingness to pay for prevention of influenza (P <.05). CONCLUSION: Employees expressed a stronger preference to prevent influenza in their children than in themselves or other household members; however, modifiable barriers depress vaccination rates.

Effect of influenza-like illness and other wintertime respiratory illnesses on worker productivity: The child and household influenza-illness and employee function (CHIEF) study.

Acute respiratory illnesses (ARI), comprising influenza-like illness (ILI) and other wintertime respiratory illnesses (ORI), impose substantial health and economic burdens on the United States. Little is known about the impact of ILI among household members (HHM), particularly children, on employees' productivity. To quantify the impact of employee and HHM-ILI and ARI on employee productivity, a prospective, observational cohort study was conducted among employees from three large US companies. Employees who had at least one child living at home (N=2013) completed a monthly survey during the 2007-2008 influenza season, reporting the number of days missed from work and hours of presenteeism due to: (1) personal ILI, (2) HHM-ILI, and (3) personal and HHM-ARI. Employee ILI ranged from 4.8% (April) to 13.5% (February). Employees reporting ILI reported more absences than employees not reporting ILI (72% vs 30%, respectively; P<0.001). Overall, 61.2% of employees surveyed had at least one child with an ILI; these employees missed more days of work due to HHM illness than employees without an ARI-ill child (0.9 days vs 0.3 days, respectively; P<0.001). Employees with ILI were less productive, on average, for 4.8h each day that they worked while sick, 2.5h of which was attributable to ILI. HHM illnesses accounted for 17.7% (1389/7868 days) of employee absenteeism, over half of which was due to HHM-ARI. ILI causes a significant amount of employee absence. Household members, particularly children, comprise a sizable proportion of general illness and injury-related employee absences.

Workshop on immunizations in older adults: identifying future research agendas.

Goals for immunization in older adults may differ from those in young adults and children, in whom complete prevention of disease is the objective. Often, reduced hospitalization and death but also averting exacerbation of underlying chronic illness, functional decline, and frailty are important goals in the older age group. Because of the effect of age on dendritic cell function, T cell-mediated immune suppression, reduced proliferative capacity of T cells, and other immune responses, the efficacy of vaccines often wanes with advanced age. This article summarizes the discussion and proceedings of a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the American Geriatrics Society, the National Institute on Aging, and the National Institute of Allergy and Infectious Diseases. Leading researchers and clinicians in the fields of immunology, epidemiology, infectious diseases, geriatrics, and gerontology reviewed the current status of vaccines in older adults, identified knowledge gaps, and suggest priority areas for future research. The goal of the workshop was to identify what is known about immunizations (efficacy, effect, and current schedule) in older adults and to recommend priorities for future research. Investigation in the areas identified has the potential to enhance understanding of the immune process in aging individuals, inform vaccine development, and lead to more-effective strategies to reduce the risk of vaccine-preventable illness in older adults.

Influenza control in the 21st century: Optimizing protection of older adults.

Older adults (> or =65 years of age) are particularly vulnerable to influenza illness. This is due to a waning immune system that reduces their ability to respond to infection, which leads to more severe cases of disease. The majority ( approximately 90%) of influenza-related deaths occur in older adults and, in addition, catastrophic disability resulting from influenza-related hospitalization represents a significant burden in this vulnerable population. Current influenza vaccines provide benefits for older adults against influenza; however, vaccine effectiveness is lower than in younger adults. In addition, antigenic drift is also a concern, as it can impact on vaccine effectiveness due to a mismatch between the vaccine virus strain and the circulating virus strain. As such, vaccines that offer higher and broader protection against both homologous and heterologous virus strains are desirable. Approaches currently available in some countries to meet this medical need in older adults may include the use of adjuvanted vaccines. Future strategies under evaluation include the use of high-dose vaccines; novel or enhanced adjuvantation of current vaccines; use of live attenuated vaccines in combination with current vaccines; DNA vaccines; recombinant vaccines; as well as the use of different modes of delivery and alternative antigens. However, to truly evaluate the benefits that these solutions offer, further efficacy and effectiveness studies, and better correlates of protection, including a precise measurement of the T cell responses that are markers for protection, are needed. While it is clear that vaccines with greater immunogenicity are required for older adults, and that adjuvanted vaccines may offer a short-term solution, further research is required to exploit the many other new technologies.

Barriers to adult immunization.

Our aim was to provide a better understanding of why many adults fail to receive recommended immunizations. Consumers (N = 2,002) and healthcare providers (N = 200) completed structured telephone interviews concerning their attitudes and knowledge about adult vaccines and factors affecting their vaccination decisions. Self-reported immunization rates for tetanus, influenza, and pneumococcal vaccines (which were emphasized in the surveys) were lower than goal rates set by national guidelines. Among the most common reasons consumers gave for not receiving immunizations were lack of physician recommendations and mistaken assumptions (e.g., healthy people do not need immunizations). Healthcare providers tended to cite concerns such as side effects, fear of needles, and lack of insurance coverage as reasons consumers forego vaccination. Providers also cited practice issues, such as lack of an effective reminder system, as barriers to increasing adult immunization rates. We conclude that a better understanding of why adults do not get vaccinated is important for efforts to increase immunization rates in this broad age group.

Cost-effectiveness of live attenuated influenza vaccine versus inactivated influenza vaccine among children aged 24-59 months in the United States.

BACKGROUND: The US Advisory Committee on Immunization Practices (ACIP) recently expanded the influenza vaccine recommendation to include children 24-59 months of age. In a large head-to-head randomized controlled trial, live attenuated influenza vaccine, trivalent (LAIV) demonstrated a 54% relative reduction in culture-confirmed influenza illness compared with trivalent inactivated influenza vaccine (TIV) among children aged 24-59 months. OBJECTIVE: To evaluate the relative cost and benefit between two influenza vaccines (LAIV and TIV) for healthy children 24-59 months of age. METHODS: Using patient-level data from the clinical trial supplemented with cost data from published literature, we modeled the cost-effectiveness of these two vaccines. Effectiveness was measured in quality-adjusted life years (QALY) and cases of influenza avoided. The analysis used the societal perspective. RESULTS: Due to its higher acquisition cost, LAIV increased vaccination costs by USD7.72 per child compared with TIV. However, compared with TIV, LAIV reduced the number of influenza illness cases and lowered the subsequent healthcare use of children and productivity losses of parents. The estimated offsets in direct and indirect costs saved USD15.80 and USD37.72 per vaccinated child, respectively. LAIV had a net total cost savings of USD45.80 per child relative to TIV. One-way and probabilistic sensitivity analyses indicated that the model was robust across a wide range of relative vaccine efficacy and cost estimates. CONCLUSIONS: Due to its increased relative vaccine efficacy over TIV, LAIV reduced the burden of influenza and lowered both direct health care and societal costs among children 24-59 months of age.

Non-traditional settings for influenza vaccination of adults: costs and cost effectiveness.

OBJECTIVE: Influenza vaccination rates remain far below national goals in the US. Expanding influenza vaccination in non-traditional settings such as worksites and pharmacies may be a way to enhance vaccination coverage for adults, but scant data exist on the cost effectiveness of this strategy. The aims of this study were to (i) describe the costs of vaccination in non-traditional settings such as pharmacies and mass vaccination clinics; and (ii) evaluate the projected health benefits, costs and cost effectiveness of delivering influenza vaccination to adults of varying ages and risk groups in non-traditional settings compared with scheduled doctor's office visits. All analyses are from the US societal perspective. METHODS: We evaluated the costs of influenza vaccination in non-traditional settings via detailed telephone interviews with representatives of organizations that conduct mass vaccination clinics and pharmacies that use pharmacists to deliver vaccinations. Next, we constructed a decision tree to compare the projected health benefits and costs of influenza vaccination delivered via non-traditional settings or during scheduled doctor's office visits with no vaccination. The target population was stratified by age (18-49, 50-64 and >or=65 years) and risk status (high or low risk for influenza-related complications). Probabilities and costs (direct and opportunity) for uncomplicated influenza illness, outpatient visits, hospitalizations, deaths, vaccination and vaccine adverse events were derived from primary data and from published and unpublished sources. RESULTS: The mean cost (year 2004 values) of vaccination was lower in mass vaccination (dollars US 17.04) and pharmacy (dollars US 11.57) settings than in scheduled doctor's office visits (dollars US 28.67). Vaccination in non-traditional settings was projected to be cost saving for healthy adults aged >or=50 years, and for high-risk adults of all ages. For healthy adults aged 18-49 years, preventing an episode of influenza would cost dollars US 90 if vaccination were delivered via the pharmacy setting, dollars US 210 via the mass vaccination setting and dollars US 870 via a scheduled doctor's office visit. Results were sensitive to assumptions on the incidence of influenza illness, the costs of vaccination (including recipient time costs) and vaccine effectiveness. CONCLUSION: Using non-traditional settings to deliver routine influenza vaccination to adults is likely to be cost saving for healthy adults aged 50-64 years and relatively cost effective for healthy adults aged 18-49 years when preferences for averted morbidity are included.

Vaccines for seasonal and pandemic influenza.

Seasonal influenza continues to have a huge annual impact in the United States, accounting for tens of millions of illnesses, hundreds of thousands of excess hospitalizations, and tens of thousands of excess deaths. Vaccination remains the mainstay for the prevention of influenza. In the United States, 2 types of influenza vaccine are currently licensed: trivalent inactivated influenza vaccine and live attenuated influenza vaccine. Both are safe and effective in the populations for which they are approved for use. Children, adults <65 years of age, and the elderly all receive substantial health benefits from vaccination. In addition, vaccination appears to be cost-effective, if not cost saving, across the age spectrum. Despite long-standing recommendations for the routine vaccination of persons in high-priority groups, US vaccination rates remain too low across all age groups. Important issues to be addressed include improving vaccine delivery to current and expanded target groups, ensuring timely availability of adequate vaccine supply, and development of even more effective vaccines. Development of a vaccine against potentially pandemic strains is an essential part of the strategy to control and prevent a pandemic outbreak. The use of existing technologies for influenza vaccine production would be the most straightforward approach, because these technologies are commercially available and licensing would be relatively simple. Approaches currently being tested include subvirion inactivated vaccines and cold-adapted, live attenuated vaccines. Preliminary results have suggested that, for some pandemic antigens, particularly H5, subvirion inactivated vaccines are poorly immunogenic, for reasons that are not clear. Data from evaluation of live pandemic vaccines are pending. Second-generation approaches designed to provide improved immune responses at lower doses have focused on adjuvants such as alum and MF59, which are currently licensed for influenza or other vaccines. Additional experimental approaches are required to achieve the ultimate goal for seasonal and pandemic influenza prevention--namely, the ability to generate broadly cross-reactive and durable protection in humans.

Health-related quality of life predicts future health care utilization and mortality in veterans with self-reported physician-diagnosed arthritis: the veterans arthritis quality of life study.

OBJECTIVE: To investigate whether health-related quality of life (HRQOL) measures predict health care utilization and mortality in a cohort of veterans with self-reported physician-diagnosed arthritis. METHODS: A cohort of veterans from the Upper Midwest Veterans Integrated Service Network (VISN) was mailed a self-administered questionnaire that was composed of the SF-36V (modified from SF-36 for use in veterans) and questions regarding demographics, current smoking status, limitation of activities of daily living (ADLs), and preexisting physician-diagnosed medical conditions, including arthritis. Within subjects reporting physician-diagnosed arthritis, we analyzed the associations between the SF-36V component summary scales (physical and mental component summary, PCS and MCS, respectively) and the occurrence of any hospitalization, number of hospitalizations, number of outpatient visits, and mortality, for the year after survey administration, using multivariable regression analyses. RESULTS: Of 34,440 survey responders who answered a question regarding arthritis, 18,464 (58%) subjects reported physician-diagnosed arthritis. Arthritic patients in the lowest tertile of PCS scores had significantly higher odds of any hospitalization (Odds ratio (OR) 1.49, 95% confidence interval (CI) [1.25-1.76]) and mortality (OR 1.69, 95% CI [1.18-2.42]), and a significantly higher number of hospitalizations/year (Rate ratio (RR) 1.09, 95% CI [1.05-1.13]) and outpatient visits/year (RR 1.07, 95% CI [1.03-1.11]). Arthritic patients in the lowest tertile of MCS scores had significantly higher odds of any hospitalization (OR 1.20, 95% CI [1.02-1.41]), mortality (OR 2.14, 95% CI [1.56-2.94]), and a significantly higher number of hospitalizations/year (RR 1.05, 95% CI [1.02-1.09]) and outpatient visits/year (RR 1.07, 95% CI [1.03-1.11]). CONCLUSIONS: HRQOL, as assessed by the SF-36V, predicts future inpatient and outpatient health care utilization and mortality in veterans with self-report of physician-diagnosed arthritis.

The Veterans Short Form 36 questionnaire is predictive of mortality and health-care utilization in a population of veterans with a self-reported diagnosis of asthma or COPD.

STUDY OBJECTIVE: Measures of health-related quality of life (HRQL) correlate with disease stage in persons with COPD. However, as their predictive capacity for mortality or medical utilization is less well defined, we sought to examine the relationship of a general measure of HRQL and outcomes in persons with obstructive lung disease. DESIGN: Prospective cohort study. SETTING: Upper Midwest Veterans Integrated Service Network (VISN)-13. PARTICIPANTS: All veterans in VISN-13 (n = 70,017) were surveyed with the Veterans Short Form 36 (SF-36V). Persons with reported asthma or COPD who completed the SF-36V formed the study cohort (n = 8,354). MEASUREMENTS AND RESULTS: For purposes of analysis, individuals were divided into quartiles of HRQL according to their physical component summary (PCS) and mental component summary (MCS), values derived from the SF-36V. Outcomes of mortality, hospitalization, and outpatient visits were recorded for 12 months after the survey. Outpatient utilization was dichotomized into high vs low use, with high use being defined as the upper quartile of visits in the 12 months prior to survey mailing. The study cohort had a mean age of 65 years and was largely male (95%), both consistent with a veteran population. After correcting for potential confounding factors through multivariable regression, the PCS was independently predictive of death, hospitalization, and high outpatient utilization. When using the first quartile of PCS as the reference population, those in the fourth quartile of PCS had a hazard ratio for death of 5.47 (95% confidence interval [CI], 3.63 to 8.26). Similarly, the odds ratios for hospitalization, high primary care visits, and high specialty medicine visits in the fourth quartile of PCS were 1.82 (95% CI, 1.51 to 2.19), 1.54 (95% CI, 1.26 to 1.87), and 1.46 (95% CI, 1.21 to 1.78), respectively. The MCS, through multivariable regression, was predictive of death but unassociated with subsequent hospitalization or high outpatient utilization. CONCLUSION: HRQL, as assessed by the SF-36V, is an independent predictor of mortality, hospitalization, and outpatient utilization in persons with self-reported obstructive lung disease.

Influence of clinical case definitions with differing levels of sensitivity and specificity on estimates of the relative and absolute health benefits of influenza vaccination among healthy working adults and implications for economic analyses.

Clinical illness case definitions for influenza and methods used to define influenza seasons can vary substantially from study to study. These differences often result in differing levels of sensitivity, specificity and positive predictive value for the case definitions used. We explored the implications of different case definitions and outcome periods on estimates of influenza vaccine effectiveness and cost benefit by conducting additional analyses of data collected from a randomized, double blind, placebo controlled trial of the trivalent, intranasal, live attenuated influenza virus vaccine in healthy working adults. Febrile upper respiratory tract illnesses occurring during the peak influenza period was identified as the most specific clinical case definition expected to have the highest positive predictive value for true influenza whereas events occurring on a day with any symptom occurring during the entire outcome period was identified as the most sensitive clinical case definition with the lowest positive predictive value for influenza. As expected, the former provided the highest estimates of vaccine effectiveness (28.4% reduction in work loss days, 24.6% reduction in days with impaired productivity and 40.9% reduction in days with health care provider visits) but the lowest estimates of absolute reductions in events (42.4 work loss days prevented per 1000, 79.0 impaired productivity days per 1000, and 16.5 days with health care provider visits per 1000). On the other hand, events on days with any symptom during the entire outcome period provided the lowest estimates of vaccine effectiveness (18% reduction in work loss days, 18% reduction in days with impaired productivity, and 13% reduction in days with health care provider visits) but the highest estimates of absolute reductions in events (186.4 work loss days per 1000, 271.5 impaired productivity days per 1000, and 44.8 days with health care provider visits per 1000). When applied to a cost benefit analysis, the more specific case definition provided a break even cost for vaccination of US$ 6.58 whereas the more sensitive case definition provided a break even cost for vaccination of US$ 43.07. Clearly the latter combination is most appropriate when trying to assess the total population level impact of a vaccine preventable disease and the potential cost effectiveness of vaccination whereas the former may be most appropriate for assessing whether the vaccine actually works. The definitions of clinical influenza illness and outcome periods should be selected to match the study question.

The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines.

Influenza is a major cause of morbidity and mortality worldwide. Currently available inactivated influenza virus vaccines are safe and effective in preventing influenza. Substantial health benefits are seen across all age and risk groups. Studies assessing the economic benefits of vaccination suggest that vaccination is highly cost effective and in many cases cost saving among the elderly. Influenza vaccination has also been associated with significant economic benefits in younger adults and children. Additional health economic studies from developing countries and from tropical/subtropical regions will be vitally important for better understanding of the global burden of influenza and potential benefits of vaccination.

Cost benefit of influenza vaccination in healthy, working adults: an economic analysis based on the results of a clinical trial of trivalent live attenuated influenza virus vaccine.

INTRODUCTION: Trivalent, intranasal, live attenuated influenza virus vaccine (LAIV) is safe and clinically effective in healthy, working adults. However, the potential economic benefits of vaccinating this population are still uncertain. We therefore conducted a cost benefit analysis of influenza vaccination of healthy working adults utilizing clinical outcome data from a trial of LAIV in healthy working adults. METHODS: This cost benefit analysis was based on the results of a multi-center, randomized, double blind placebo controlled trial that assessed the clinical effectiveness of LAIV in healthy working adults. Outcomes from the trial that were included in the cost benefit analysis were days of work missed, days working but at reduced effectiveness, and days with a health care provider visit due to at least one of the following symptoms: fever, runny nose, sore throat, cough, headache, muscle aches, chills, or tiredness/weakness. Cost data were obtained from nationally representative databases. Probability distributions for the key model variables were defined, and Monte Carlo simulation was used to estimate the mean break even costs for vaccine and its administration. Sensitivity analyses explored how changes in the variables affected these estimates. RESULTS: There were 4561 participants in the clinical trial. LAIV lowered work loss due to illness symptoms by 18% (relative rate [RR] 0.82, 95% confidence interval [CI] 0.74-0.91), days of working at reduced effectiveness by 18% (RR 0.82, 95% CI 0.74-0.91), and days with a health care provider visit by 13% (RR 0.87, 95% CI 0.77-0.98). The mean break even cost for vaccine and its administration was 43.07 US dollars per person vaccinated (5-95% percentiles, 25.72-58.92 US dollars). Major cost drivers were hourly wage and vaccine effectiveness in reducing productivity losses and health care use. CONCLUSION: This cost benefit analysis based on the results of the LAIV trial provides additional evidence that influenza vaccination may provide both health and economic benefits for healthy, working adults.

Influence of high-risk medical conditions on the effectiveness of influenza vaccination among elderly members of 3 large managed-care organizations.

This serial cohort study assessed the risk of hospitalization or death associated with influenza and the effectiveness of influenza vaccination among subgroups of elderly members of 3 managed-care organizations in the United States. Data on baseline characteristics and outcomes were obtained from computerized databases. A total of 122,974 (1996-1997 season) and 158,454 (1997-1998 season) persons were included in the cohorts. Among unvaccinated persons, hospitalizations for pneumonia/influenza or death occurred in 8.2 of 1000 healthy and 38.4 of 1000 high-risk persons in year 1, and in 8.2 of 1000 healthy and 29.3 of 1000 high-risk persons in year 2. After adjustments, vaccination was associated with a 48% reduction in the incidence of hospitalization or death (95% confidence interval [CI], 42-52) in year 1 and 31% (95% CI, 26-37) in year 2. Effectiveness estimates were statistically significant and generally consistent across the healthy and high-risk subgroups. The absolute risk reduction, however, was 2.4- to 4.7-fold higher among high-risk than among healthy elderly persons. All elderly individuals may substantially benefit from vaccination. However, the impact of influenza is greater in persons with high-risk medical conditions.

Cost effectiveness of influenza vaccination for healthy persons between ages 65 and 74 years.

Healthy persons between 65 and 74 years of age represent a large proportion of the population in this age group. Internationally, there is a substantial variation in whether these people are included among the recommendations for routine influenza vaccination. We therefore conducted this study, updating an earlier analysis, to assess the health and economic benefits of routine influenza vaccination of healthy persons between 65 and 74 years of age. The health benefits associated with vaccination were estimated using the administrative data bases of a large HMO in the Minneapolis, St. Paul, Minnesota area. Multivariate models were used to estimate reductions in hospitalization and death associated with vaccination. The economic analysis took the societal perspective and presented the results as net cost or saving per 10,000 persons vaccinated and per death prevented. Direct and indirect monetary costs were included in the models and were estimated from the published literature. Monte Carlo simulation was used to conduct probabilistic sensitivity analysis in order to derive probability intervals for each estimate of net costs or savings. Over the six consecutive study seasons, 1990-1991 to 1995-1996, vaccination of healthy elderly person was associated with a 36% reduction in hospitalization for pneumonia or influenza (95% CI, 2-39%), an 18% reduction in hospitalization for all respiratory conditions (95% CI, -6 to 37%) and a 40% reduction in death (95% CI, 14-38%). Vaccination was also associated with cost savings in all scenarios evaluated. The findings of this study again affirm the value of an age-based strategy for routine influenza vaccination of all elderly persons including healthy elderly persons between 65 and 74 years.

Immunization for seniors.

Vaccine-preventable diseases remain a significant health problem for adults in the United States. Far more adults die from the complications of vaccine-preventable diseases than do children in this country. Available vaccines that are effective in preventing morbidity and mortality from these conditions are underutilized, and significant racial and ethnic disparities in rates of utilization of adult vaccines persist. A variety of important vaccine-preventable diseases affect seniors. However, influenza and pneumococcal infections stand out as being responsible for more cases and more deaths each year among seniors than all other vaccine-preventable diseases in the United States combined. Current vaccination rates for these two diseases are far short of the Healthy People 2010 target rates of 90% immunization of the population of adults aged 65 years or over. Despite state efforts to improve vaccination rates of seniors, efforts that have included regulatory and educational approaches, significant challenges remain in designing immunization programs for seniors that are universally effective.