How Does the Burden of Respiratory Syncytial Virus Compare to Influenza in Spanish Adults?

BACKGROUND: Respiratory syncytial virus (RSV) and influenza infections cause significant annual morbidity and mortality worldwide in at-risk populations. This study is aimed at assessing hospital burden and healthcare resource utilization (HRU) of RSV and influenza in adults in Spain. METHODS: Data were obtained from the Projected Hospitalisation Database of inpatient episodes (ages: younger adults 18-50 and 51-64 years; older adults 65-74, 75-84, and ≥ 85 years) during 2015, 2017, and 2018 in Spanish public hospitals. Incidence, mean hospitalization, and HRU assessments, including length of stay (LOS), intensive care unit (ICU) usage, and age-standardized mortality rates, were collected and stratified by age group, with analyses focusing on the adult population (≥ 18 years old). RESULTS: Mean hospitalization rate in the population across all years was lower in individuals with RSV versus influenza (7.2/100,000 vs. 49.7/100,000 individuals). ICU admissions and median LOS were similar by age group for both viruses. Age-standardized mortality was 6.3/100,000 individuals and 6.1/100,000 individuals in patients with RSV and influenza, respectively, and mortality rates were similar in older adults (≥ 65 years) for both viruses. CONCLUSIONS: RSV and influenza infection were associated with considerable HRU. There is a substantial disease burden for RSV infection in older adults ≥ 65 years. While RSV hospitalization rates in adults reported here appeared lower than influenza, RSV is still underdiagnosed in the hospital setting and its incidence might be similar to, or higher than, influenza.

The Hospital Burden of Flu in Italy: a retrospective study on administrative data from season 2014-2015 to 2018-2019.

BACKGROUND: Every year in Italy, influenza affects about 4 million people. Almost 5% of them are hospitalised. During peak illness, enormous pressure is placed on healthcare and economic systems. This study aims to quantify the clinical and economic burden of severe influenza during 5 epidemic seasons (2014-2019) from administrative claims data. METHODS: Patients hospitalized with a diagnosis of influenza between October 2014, and April 2019, were analyzed. Clinical characteristics and administrative information were retrieved from health-related Administrative Databases (ADs) of 4 Italian Local Health Units (LHUs). The date of first admission was set as the Index Date (ID). A follow-up period of six months after ID was considered to account for complications and re-hospitalizations, while a lookback period (2 years before ID) was set to assess the prevalence of underlying comorbidities. RESULTS: Out of 2,333 patients with severe influenza, 44.1% were adults ≥ 65, and 25.6% young individuals aged 0-17. 46.8% had comorbidities (i.e., were at risk), mainly cardiovascular and metabolic diseases (45.3%), and chronic conditions (24.7%). The highest hospitalization rates were among the elderly (≥ 75) and the young individuals (0-17), and were 37.6 and 19.5/100,000 inhabitants/year, respectively. The average hospital stay was 8 days (IQR: 14 - 4). It was higher for older individuals (≥ 65 years, 11 days, [17 - 6]) and for those with comorbidities (9 days, [16 - 6]), p-value < 0.001. Similarly, mortality was higher in elderly and those at risk (p-value < 0.001). Respiratory complications occurred in 12.7% of patients, and cardiovascular disorders in 5.9%. Total influenza-related costs were €9.7 million with hospitalization accounting for 95% of them. 47.3% of hospitalization costs were associated with individuals ≥ 65 and 52.9% with patients at risk. The average hospitalisation cost per patient was € 4,007. CONCLUSIONS: This retrospective study showed that during the 2014-2019 influenza seasons in Italy, individuals of extreme ages and those with pre-existing medical conditions, were more likely to be hospitalized with severe influenza. Together with complications and ageing, they worsen patient's outcome and may lead to a prolonged hospitalization, thus increasing healthcare utilization and costs. Our data generate real-world evidence on the burden of influenza, useful to inform public health decision-making.

Why Does Influenza Hit the Poor More Than the Rich? A 1931 Social Epidemiology Article That Broke New Ground in the History of Confounding, Mediation, and Interaction.

In 1931, Edgar Sydenstricker, the former statistician of the US Public Health Service, challenged the common belief that the 1918 influenza outbreak had affected "the rich and the poor alike." Using data from 112,317 participants in a 1918 US national survey, he observed that, on the contrary, both morbidity and mortality from the flu had been higher among the poor than among the rich. To explain these differences, Sydenstricker stratified the analyses by 2 measures of affluence collected in the survey: "economic status" (from "very poor" to "well-to-do") and household crowding (i.e., number of people per household room). Economic status was associated with influenza attack rates within categories of crowding, but not the opposite, suggesting that characteristics of poverty other than "household congestion" were the culprit of the poor's higher influenza burden. Attack rate ratios for influenza in infants and older adults were greater for the poor or very poor. Sydenstricker reanalyzed an already 12-year-old data set in the context of the Great Depression to build the evidence base relating poverty to ill health. For this purpose he used a stratification approach to assess confounding, mediation, and interaction before the concepts were formally named.

Impact of comorbidities on mortality in hospitalized influenza patients with diabetes - Analysis of the Austrian Health Insurance.

AIMS: To assess the impact of characteristics and comorbidities on the hospitalization rate and 30- and 90-days all-cause mortality after hospitalization for influenza-related illness (IRI) in individuals with diabetes. METHODS: Data of 507,184 individuals with diabetes enrolled in the national Austrian Health Insurance database during 2013-2017 were analyzed. Hospitalization for IRI was defined as per International Classification of Disease 10 codes (J09, J10, J11). All-cause mortality was calculated for 30- and 90-days post-hospitalization. RESULTS: Of the total diabetes population, 1994 (0.4%) were hospitalized for IRI during 2013-2017. The rate of comorbidities was higher in individiuals who were hospitalized due to IRI as compared with the general diabetes population. Overall 30-days cumulative mortality following hospitalization for IRI was 7.9% and 90-days mortality was 10.3%. The risk (adjusted Hazard Ratio, 95% Confidence Interval) of IRI related 90-days mortality increased with age (50-59: 3.00, 0.65-13.94; 60-69: 4.16, 0.99-17.55; 70-79: 4.79, 1.16-19.76; 80+: 7.15, 1.74-29.46), heart failure (1.97, 1.31-2.98), renal disease (1.50, 1.05-2.14), and Charlson comorbidity index (1.14, 1.08-1.19). CONCLUSIONS: Older age, heart failure, renal disease, and Charlson comorbidity index were significant predictors of mortality following hospitalization for IRI in individuals with diabetes. These findings could help in improving the clinical management and performance of surveillance and health systems concerning IRI in Austria.

Influenza-associated disease burden in mainland China: a systematic review and meta-analysis.

Influenza causes substantial morbidity and mortality. Many original studies have been carried out to estimate disease burden of influenza in mainland China, while the full disease burden has not yet been systematically reviewed. We did a systematic review and meta-analysis to assess the burden of influenza-associated mortality, hospitalization, and outpatient visit in mainland China. We searched 3 English and 4 Chinese databases with studies published from 2005 to 2019. Studies reporting population-based rates of mortality, hospitalization, or outpatient visit attributed to seasonal influenza were included in the analysis. Fixed-effects or random-effects model was used to calculate pooled estimates of influenza-associated mortality depending on the degree of heterogeneity. Meta-regression was applied to explore the sources of heterogeneity. Publication bias was assessed by funnel plots and Egger's test. We identified 30 studies eligible for inclusion with 17, 8, 5 studies reporting mortality, hospitalization, and outpatient visit associated with influenza, respectively. The pooled influenza-associated all-cause mortality rates were 14.33 and 122.79 per 100,000 persons for all ages and ≥ 65 years age groups, respectively. Studies were highly heterogeneous in aspects of age group, cause of death, statistical model, geographic location, and study period, and these factors could explain 60.14% of the heterogeneity in influenza-associated mortality. No significant publication bias existed in estimates of influenza-associated all-cause mortality. Children aged < 5 years were observed with the highest rates of influenza-associated hospitalizations and ILI outpatient visits. People aged ≥ 65 years and < 5 years contribute mostly to mortality and morbidity burden due to influenza, which calls for targeted vaccination policy for older adults and younger children in mainland China.

Geographic Variation in Racial Disparities in Mortality From Influenza and Pneumonia in the United States in the Pre-Coronavirus Disease 2019 Era.

BACKGROUND: In 2018, influenza and pneumonia was the eighth leading cause of death in the United States. Since 1950, non-Hispanic blacks (NHBs) have experienced higher rates of mortality than non-Hispanic whites (NHWs). Previous studies have revealed geographic variation in mortality rates by race. The identification of areas with the greatest disparity in influenza and pneumonia mortality may assist policymakers in the allocation of resources, including for the coronavirus disease 2019 pandemic. RESEARCH QUESTION: Does geographic variation in racial disparity in influenza and pneumonia mortality exist? STUDY DESIGN AND METHODS: The Centers for Disease Control and Prevention database for Multiple Cause of Death between 1999 and 2018 for NHB and NHW decedents ≥ 25 years of age with a Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems code for influenza (J09-J11) and pneumonia (J12-J18) was used. Age-adjusted mortality rates (AAMRs) with 95% CIs were computed by race for Health & Human Services (HHS) regions and urbanization in NHBs and NHWs. RESULTS: In 1999 through 2018, there were 540,476 deaths among NHBs and NHWs 25 to 84 years of age. AAMRs were higher in NHBs than NHWs in each age group and in seven of 10 HHS regions. The greatest disparity was in HHS regions 2 (New York and New Jersey) and 9 (Arizona, California, Hawaii, and Nevada). In HHS region 2, NHBs (24.6; 95% CI, 24.1-25.1) were more likely to die than NHWs (15.7; 95% CI, 15.6-15.9). Similarly, in region 9, NHBs (23.2; 95% CI, 22.7-23.8) had higher mortality than NHWs (16.1; 95% CI, 15.9-16.2). Within these regions, disparities were greatest in the core of major metropolitan areas. A very high AAMR in NHBs was noted in large, central metropolitan areas of region 2: 28.2 (95% CI, 27.6-28.9). INTERPRETATION: In 1999 through 2018, the NHB-NHW disparity in AAMRs from influenza and pneumonia was greatest in central metropolitan areas of HHS regions 2 and 9.

Point-of-care diagnostic tests for influenza in the emergency department: A cost-effectiveness analysis in a high-risk population from a Canadian perspective.

BACKGROUND: Our objective was to assess the cost-effectiveness of novel rapid diagnostic tests: rapid influenza diagnostic tests (RIDT), digital immunoassays (DIA), rapid nucleic acid amplification tests (NAAT), and other treatment algorithms for influenza in high-risk patients presenting to hospital with influenza-like illness (ILI). METHODS: We developed a decision-analytic model to assess the cost-effectiveness of diagnostic test strategies (RIDT, DIA, NAAT, clinical judgement, batch polymerase chain reaction) preceding treatment; no diagnostic testing and treating everyone; and not treating anyone. We modeled high-risk 65-year old patients from a health payer perspective and accrued outcomes over a patient's lifetime. We reported health outcomes, quality-adjusted life years (QALYs), healthcare costs, and net health benefit (NHB) to measure cost-effectiveness per cohort of 100,000 patients. RESULTS: Treating everyone with no prior testing was the most cost-effective strategy, at a cost-effectiveness threshold of $50,000/QALY, in over 85% of simulations. This strategy yielded the highest NHB of 15.0344 QALYs, but inappropriately treats all patients without influenza. Of the novel rapid diagnostics, NAAT resulted in the highest NHB (15.0277 QALYs), and the least number of deaths (1,571 per 100,000). Sensitivity analyses determined that results were most impacted by the pretest probability of ILI being influenza, diagnostic test sensitivity, and treatment effectiveness. CONCLUSIONS: Based on our model, treating high-risk patients presenting to hospital with influenza-like illness, without performing a novel rapid diagnostic test, resulted in the highest NHB and was most cost-effective. However, consideration of whether treatment is appropriate in the absence of diagnostic confirmation should be taken into account for decision-making by clinicians and policymakers.

Estimation of Excess Deaths Associated With the COVID-19 Pandemic in the United States, March to May 2020.

Importance: Efforts to track the severity and public health impact of coronavirus disease 2019 (COVID-19) in the United States have been hampered by state-level differences in diagnostic test availability, differing strategies for prioritization of individuals for testing, and delays between testing and reporting. Evaluating unexplained increases in deaths due to all causes or attributed to nonspecific outcomes, such as pneumonia and influenza, can provide a more complete picture of the burden of COVID-19. Objective: To estimate the burden of all deaths related to COVID-19 in the United States from March to May 2020. Design, Setting, and Population: This observational study evaluated the numbers of US deaths from any cause and deaths from pneumonia, influenza, and/or COVID-19 from March 1 through May 30, 2020, using public data of the entire US population from the National Center for Health Statistics (NCHS). These numbers were compared with those from the same period of previous years. All data analyzed were accessed on June 12, 2020. Main Outcomes and Measures: Increases in weekly deaths due to any cause or deaths due to pneumonia/influenza/COVID-19 above a baseline, which was adjusted for time of year, influenza activity, and reporting delays. These estimates were compared with reported deaths attributed to COVID-19 and with testing data. Results: There were approximately 781 000 total deaths in the United States from March 1 to May 30, 2020, representing 122 300 (95% prediction interval, 116 800-127 000) more deaths than would typically be expected at that time of year. There were 95 235 reported deaths officially attributed to COVID-19 from March 1 to May 30, 2020. The number of excess all-cause deaths was 28% higher than the official tally of COVID-19-reported deaths during that period. In several states, these deaths occurred before increases in the availability of COVID-19 diagnostic tests and were not counted in official COVID-19 death records. There was substantial variability between states in the difference between official COVID-19 deaths and the estimated burden of excess deaths. Conclusions and Relevance: Excess deaths provide an estimate of the full COVID-19 burden and indicate that official tallies likely undercount deaths due to the virus. The mortality burden and the completeness of the tallies vary markedly between states.

Influenza-Associated Aspergillosis: Nationwide Trends, Predictors and Outcomes From 2005 to 2014.

BACKGROUND: Influenza-associated aspergillosis (IAA) has been increasingly reported in the literature in recent years, but contemporary large-scale data on the morbidity and mortality burden of IAA are lacking. RESEARCH QUESTION: The goal of this study was to estimate the predictors, associations, and outcomes of IAA in the United States. STUDY DESIGN AND METHODS: This retrospective cohort study was performed by using the National (Nationwide) Inpatient Sample database from 2005 to 2014 to identify influenza and IAA hospitalizations. Baseline variables and outcomes were compared between influenza hospitalizations without IAA and those with IAA. These variables were then used to perform an adjusted analysis for obtaining predictors and associations of the diagnosis and in-hospital mortality of IAA. RESULTS: Of the 477,556 hospitalizations identified with the principal diagnosis of influenza, IAA was identified in 823 (0.17%) hospitalizations. The IAA cohort consisted more commonly of 45- to 65-year-olds in urban teaching hospitals with substance abuse. Yearly trends revealed that both influenza and IAA hospitalizations have increased over time, with a peak observed in 2009, the year of the influenza A(H1N1) pandemic. Mortality was higher (20.58% vs 1.36%), average length of stay was longer (17.94 vs 4.05 days), and mean cost per hospitalization was higher ($194,932 vs $24,286) in the IAA cohort compared with the influenza cohort without IAA (P < .005). Solid-organ transplantation, hematologic malignancies, and use of invasive mechanical ventilation were associated with higher odds of IAA, among other factors. Use of invasive mechanical ventilation (adjusted OR, 13.43; P < .005), longer length of stay (adjusted OR, 5.47; P < .005), utilization of extracorporeal membrane oxygenation (adjusted OR, 4.99; P = .014), and the group aged 45 to 64 years (adjusted OR, 3.03; P = .012) were associated with higher in-hospital mortality in the IAA cohort. INTERPRETATION: Although IAA is a rare complication of influenza hospitalizations, it is associated with increased all-cause mortality, more extended hospital stays, and higher hospital charges compared with influenza without IAA.

High-dose influenza vaccination and mortality among predominantly male, white, senior veterans, United States, 2012/13 to 2014/15.

IntroductionIt is unclear whether high-dose influenza vaccine (HD) is more effective at reducing mortality among seniors.AimThis study aimed to evaluate the relative vaccine effectiveness (rVE) of HD. MethodsWe linked electronic medical record databases in the Veterans Health Administration (VHA) and Medicare administrative files to examine the rVE of HD vs standard-dose influenza vaccines (SD) in preventing influenza/pneumonia-associated and cardiorespiratory mortality among VHA-enrolled veterans 65 years or older during the 2012/13, 2013/14 and 2014/15 influenza seasons. A multivariable Cox proportional hazards model was performed on matched recipients of HD vs SD, based on vaccination time, location, age, sex, ethnicity and VHA priority level. ResultsAmong 569,552 person-seasons of observation, 207,574 (36%) were HD recipients and 361,978 (64%) were SD recipients, predominantly male (99%) and white (82%). Pooling findings from all three seasons, the adjusted rVE estimate of HD vs SD during the high influenza periods was 42% (95% confidence interval (CI): 24-59) against influenza/pneumonia-associated mortality and 27% (95% CI: 23-32) against cardiorespiratory mortality. Residual confounding was evident in both early and late influenza periods despite matching and multivariable adjustment. Excluding individuals with high 1-year predicted mortality at baseline reduced the residual confounding and yielded rVE of 36% (95% CI: 10-62) and 25% (95% CI: 12-38) against influenza/pneumonia-associated and cardiorespiratory mortality, respectively. These were confirmed by results from two-stage residual inclusion estimations.DiscussionThe HD was associated with a lower risk of influenza/pneumonia-associated and cardiorespiratory death in men during the high influenza period.

Seroprevalence of H7N9 infection among humans: A systematic review and meta-analysis.

In spring 2013, a novel avian-origin influenza A (H7N9) virus emerged in mainland China. The burden of H7N9 infection was estimated based on systematic review and meta-analysis. The systematic search for available literature was conducted using Chinese and English databases. We calculated the pooled seroprevalence of H7N9 infection and its 95% confidence interval by using Freeman-Tukey double arcsine transformation. Out of 16 890 records found using Chinese and English databases, 54 articles were included in the meta-analysis. These included studies of a total of 64 107 individuals. The pooled seroprevalence of H7N9 infection among humans was 0.122% (95% CI: 0.023, 0.275). In high-risk populations, the highest pooled seroprevalence was observed among close contacts (1.075%, 95% CI: 0.000, 4.357). The seroprevalence among general population was (0.077%, 95% CI: 0.011, 0.180). Our study discovered that asymptomatic infection of H7N9 virus did occur, even if the seroprevalence among humans was low.

Influenza in the school-aged population in Mexico: burden of disease and cost-effectiveness of vaccination in children.

BACKGROUND: The current national influenza vaccination schedule in Mexico does not recommend vaccination in the school-aged population (5-11 years). Currently, there are limited data from middle-income countries analysing the cost-effectiveness of influenza vaccination in this population. We explored the clinical effects and economic benefits of expanding the current national influenza vaccination schedule in Mexico to include the school-aged population. METHODS: A static 1-year model incorporating herd effect was used to assess the cost-effectiveness of expanding the current national influenza vaccination schedule of Mexico to include the school-aged population. We performed a cross-sectional epidemiological study using influenza records (2009-2018), death records (2010-2015), and discharge and hospitalisation records (2010-2016), from the databases of Mexico's Influenza Surveillance System (SISVEFLU), the National Mortality Epidemiological and Statistical System (SEED), and the Automated Hospital Discharge System (SAEH), respectively. Cost estimates for influenza cases were based on 7 scenarios using data analysed from SISVEFLU; assumptions for clinical management of cases were defined according to Mexico's national clinical guidelines. The primary health outcome for this study was the number of influenza cases avoided. A sensitivity analysis was performed using conservative and optimistic parameters (vaccination coverage: 30% / 70%, Vaccine effectiveness: 19% / 68%). RESULTS: It was estimated that expanding the influenza immunisation programme to cover school-aged population in Mexico over the 2018-2019 influenza season would result in 671,461 cases of influenza avoided (50% coverage and 50% effectiveness assumed). Associated with this were 262,800 fewer outpatient consultations; 154,100 fewer emergency room consultations; 97,600 fewer hospitalisations, and 15 fewer deaths. Analysis of cases avoided by age-group showed that 55.4% of them were in the school-aged population, and the decrease in outpatient consultations was largest in this population. There was an overall decrease in the economic burden for the Mexican health care system of 111.9 million US dollars; the immunization programme was determined to be cost-saving in the base, conservative and optimistic scenarios. CONCLUSIONS: Vaccinating school-aged population in Mexico would be cost-effective; expansion of the current national vaccination schedule to this age group is supported.

Cost-effectiveness of inactivated influenza vaccination in children with medical risk conditions in the Netherlands.

BACKGROUND: In many countries, annual immunization with inactivated influenza vaccine (IIV) is recommended for children with medical risk conditions. Prior cost-effectiveness analyses found such immunization to be cost saving, but assumed effectiveness against non-severe influenza outcomes and a higher effectiveness against severe influenza outcomes than recent studies would suggest. However, recent vaccine studies do not indicate any reduction in community or outpatient disease episodes in IIV immunized individuals. We therefore evaluated cost-effectiveness of IIV immunization in children with medical risk conditions in the Netherlands, assuming that IIV reduces influenza-related hospitalization and death, but has no meaningful impact on non-severe health outcomes. METHODS: A health economic decision tree model was developed to evaluate health effects and costs of annual IIV immunization versus no immunization. Model inputs were based on our study on influenza-related primary care visits and other literature. Immunization was considered cost effective if associated costs were less than €20,000 per quality-adjusted life year (QALY) gained. Probabilistic sensitivity analyses were performed to assess robustness of results, and one-way sensitivity analyses and scenario analyses were done to assess the influence of individual parameters. RESULTS: Annual IIV prevents an average of 1.59 influenza-related hospitalizations and 0.02 deaths per 1,000 children with medical risk conditions. This results in an expected QALY gain of 0.43 at incremental costs of €21,564 per 1,000 children, corresponding to an incremental cost-effectiveness ratio (ICER) of €50,297/QALY compared to no immunization. Under base case assumptions, immunization had a 5% probability of being cost effective. Results were most influenced by vaccine efficacy against fatal influenza, QALY loss due to death, and mortality rate. CONCLUSIONS: If IIV only reduces severe disease outcomes, as current evidence suggests, annual immunization of medical risk children is unlikely to be cost effective. Results should however be interpreted with caution as cost-effectiveness is largely dependent on incidence and QALY losses for fatal influenza, for which evidence is scarce.

Should we be vaccinating our patients against influenza?

There is a long history of vaccination administration from the Emergency Department. The morbidity, mortality and economic costs from influenza are staggering and an increasing body of literature supports initiatives for influenza vaccination from the Emergency Department. This article calls attention to this opportunity for Emergency Physicians to fill an unmet need with minimal impact to work-flow.

Estimating the Effect of a National Pharmacy-Led Influenza Vaccination Voucher Program on Morbidity, Mortality, and Costs.

BACKGROUND: Influenza (also known as "flu") is estimated to cause between 12,000 and 79,000 deaths annually. Vaccinations are beneficial in preventing influenza cases and reducing the likelihood of severe outcomes. Unfortunately, vaccination coverage is low among uninsured populations. Removing the cost barrier can help increase vaccination coverage in this group, averting flu cases and related morbidity and costs. OBJECTIVE: To model the potential effect of providing no-cost flu vaccinations to uninsured individuals on influenza-related morbidity, mortality, and costs. METHODS: In collaboration with the Department of Health and Human Services and local agencies, Walgreens pharmacies provided free flu vaccinations through a nationwide voucher distribution program. We calculated the redemption rate, potentially averted cases, and estimated cost savings for the 2015-2016 and 2016-2017 flu seasons. Using incidence and vaccine effectiveness estimates from the Centers for Disease Control and Prevention, we calculated the rate of influenza in the general population and the estimated cases averted based on the number of redeemed vouchers. We applied patient age along with parameters from published studies to estimate averted ambulatory care visits, hospitalizations, mortality, productively losses, and overall related costs. RESULTS: During the 2015-2016 flu season, the pharmacy chain distributed 600,000 vouchers with a redemption rate of 52.3%, resulting in 314,033 flu vaccinations. Improvements were subsequently made to the distribution process to increase utilization rates. There were 400,000 vouchers distributed during the 2016-2017 season with a higher redemption rate of 87.2%, resulting in 348,924 flu vaccinations. The estimated number of potentially averted cases was higher during the 2016-2017 season (13,347) than the 2015-2016 season (11,537) due to a higher redemption rate and increased flu activity. Taken together, we estimated that 8,621 ambulatory care visits, 314 hospitalizations, and 15 deaths were averted due to the flu voucher program. Averted health care costs totaled $937,494 in ambulatory care visits and $3,510,055 in hospitalizations. Averted productivity losses ranged from $4,473,509 to $14,613,502. CONCLUSIONS: This study demonstrates the effectiveness of a pharmacy-led partnership with local community-based organizations to promote flu vaccinations among uninsured individuals. Our model found that a no-cost flu voucher program has the potential to reduce influenza-related morbidity, mortality, and costs. DISCLOSURES: This study was funded by Walgreen Co. All authors are employees of Walgreen Co. and affiliated with Walgreens Center for Health and Wellbeing Research. Findings from this study were presented as a podium presentation at the Academy of Managed Care Pharmacy Nexus 2018; October 22-25, 2018; Orlando, FL.

Cost-Effectiveness Analysis for Influenza Vaccination Coverage and Timing in Tropical and Subtropical Climate Settings: A Modeling Study.

BACKGROUND: The lack of seasonality in influenza epidemics in the tropics makes the application of well-established temperate zone national vaccination plans challenging. OBJECTIVES: We developed an individual-based simulation model to study optimal vaccination scheduling and assess cost-effectiveness of these vaccination schedules in scenarios of no influenza seasonality and the seasonality regimes of Singapore, Taipei, and Tokyo. METHODS: The simulation models heterogeneities in human contact networks, levels of protective antibodies following infection, the effectiveness of the influenza vaccine, and seasonality. Using a no intervention baseline, we consider 3 alternative vaccination strategies: (1) annual vaccination for a percentage of the elderly, (2) biannual vaccination for a percentage of the elderly, and (3) annual vaccination for all elderly and a fraction of the remaining population. We considered 5 vaccination uptake rates for each strategy and modeled the estimated costs, quality-adjusted life years, and incremental cost-effectiveness ratios (ICERs), indicating the cost-effectiveness of each scenario. RESULTS: In Singapore, annual vaccination for a proportion of elderly is largely cost-effective. However, with fixed uptake rates, partial biannual vaccination for the elderly yields a higher ICER than partial annual vaccination for the elderly, resulting in a cost-ineffective ICER. The most optimal strategy is the total vaccination of all the elderly and a proportion of individuals from other age groups, which results in a cost-saving ICER. This finding is consistent across different seasonality regimes. CONCLUSIONS: Tropical countries like Singapore can have comparably cost-effective vaccination strategies as found in countries with winter epidemics. The vaccination of all the elderly and a proportion of other age groups is the most cost-effective strategy, supporting the need for an extensive national influenza vaccination program.